Showing papers on "Tumour heterogeneity published in 2016"
TL;DR: In this article, the authors employ CAPP-Seq ctDNA analysis to study resistance mechanisms in 43 non-small cell lung cancer (NSCLC) patients treated with the third-generation epidermal growth factor receptor (EGFR) inhibitor rociletinib.
Abstract: Circulating tumour DNA (ctDNA) analysis facilitates studies of tumour heterogeneity. Here we employ CAPP-Seq ctDNA analysis to study resistance mechanisms in 43 non-small cell lung cancer (NSCLC) patients treated with the third-generation epidermal growth factor receptor (EGFR) inhibitor rociletinib. We observe multiple resistance mechanisms in 46% of patients after treatment with first-line inhibitors, indicating frequent intra-patient heterogeneity. Rociletinib resistance recurrently involves MET, EGFR, PIK3CA, ERRB2, KRAS and RB1. We describe a novel EGFR L798I mutation and find that EGFR C797S, which arises in ∼33% of patients after osimertinib treatment, occurs in <3% after rociletinib. Increased MET copy number is the most frequent rociletinib resistance mechanism in this cohort and patients with multiple pre-existing mechanisms (T790M and MET) experience inferior responses. Similarly, rociletinib-resistant xenografts develop MET amplification that can be overcome with the MET inhibitor crizotinib. These results underscore the importance of tumour heterogeneity in NSCLC and the utility of ctDNA-based resistance mechanism assessment.
526 citations
TL;DR: It is observed that epigenetic allele burden is linked to inferior outcome and varies considerably during disease progression, and genetic and epigenetic heterogeneity can occur with distinct kinetics likely to affect the biological and clinical features of tumors.
Abstract: Genetic heterogeneity contributes to clinical outcome and progression of most tumors, but little is known about allelic diversity for epigenetic compartments, and almost no data exist for acute myeloid leukemia (AML). We examined epigenetic heterogeneity as assessed by cytosine methylation within defined genomic loci with four CpGs (epialleles), somatic mutations, and transcriptomes of AML patient samples at serial time points. We observed that epigenetic allele burden is linked to inferior outcome and varies considerably during disease progression. Epigenetic and genetic allelic burden and patterning followed different patterns and kinetics during disease progression. We observed a subset of AMLs with high epiallele and low somatic mutation burden at diagnosis, a subset with high somatic mutation and lower epiallele burdens at diagnosis, and a subset with a mixed profile, suggesting distinct modes of tumor heterogeneity. Genes linked to promoter-associated epiallele shifts during tumor progression showed increased single-cell transcriptional variance and differential expression, suggesting functional impact on gene regulation. Thus, genetic and epigenetic heterogeneity can occur with distinct kinetics likely to affect the biological and clinical features of tumors.
289 citations
TL;DR: It is shown that the core region of solid tumours displayed glutamine deficiency compared with other amino acids, which led to dramatic histone hypermethylation due to decreased α-ketoglutarate levels, a key cofactor for the Jumonji-domain-containing histone demethylases.
Abstract: Poorly organized tumour vasculature often results in areas of limited nutrient supply and hypoxia. Despite our understanding of solid tumour responses to hypoxia, how nutrient deprivation regionally affects tumour growth and therapeutic response is poorly understood. Here, we show that the core region of solid tumours displayed glutamine deficiency compared with other amino acids. Low glutamine in tumour core regions led to dramatic histone hypermethylation due to decreased α-ketoglutarate levels, a key cofactor for the Jumonji-domain-containing histone demethylases. Using patient-derived ^(V600E)BRAF melanoma cells, we found that low-glutamine-induced histone hypermethylation resulted in cancer cell dedifferentiation and resistance to BRAF inhibitor treatment, which was largely mediated by methylation on H3K27, as knockdown of the H3K27-specific demethylase KDM6B and the methyltransferase EZH2 respectively reproduced and attenuated the low-glutamine effects in vitro and in vivo. Thus, intratumoral regional variation in the nutritional microenvironment contributes to tumour heterogeneity and therapeutic response.
255 citations
TL;DR: Cell-free tumour DNA can be detected in plasma and urine, even in patients with noninvasive disease, with high levels of tumours DNA detectable before progression, especially in urine samples.
169 citations
TL;DR: The results demonstrate the prognostic and predictive power of the CES, suggest a role for centromere misregulation in cancer progression, and support the idea that tumours with extremely high CIN are less tolerant to specific genotoxic therapies.
Abstract: Chromosomal instability (CIN) is a hallmark of cancer that contributes to tumour heterogeneity and other malignant properties. Aberrant centromere and kinetochore function causes CIN through chromosome missegregation, leading to aneuploidy, rearrangements and micronucleus formation. Here we develop a Centromere and kinetochore gene Expression Score (CES) signature that quantifies the centromere and kinetochore gene misexpression in cancers. High CES values correlate with increased levels of genomic instability and several specific adverse tumour properties, and prognosticate poor patient survival for breast and lung cancers, especially early-stage tumours. They also signify high levels of genomic instability that sensitize cancer cells to additional genotoxicity. Thus, the CES signature forecasts patient response to adjuvant chemotherapy or radiotherapy. Our results demonstrate the prognostic and predictive power of the CES, suggest a role for centromere misregulation in cancer progression, and support the idea that tumours with extremely high CIN are less tolerant to specific genotoxic therapies.
151 citations
TL;DR: Functionally, direct inhibition of either miRNA with locked nucleic acid administered systemically, can arrest the growth of established patient-derived xenograft tumours, thus indicating that these miRNAs are clinically useful as biomarkers for tracking disease progression and as therapeutic targets.
Abstract: The tumour-initiating cell (TIC) model accounts for phenotypic and functional heterogeneity among tumour cells. MicroRNAs (miRNAs) are regulatory molecules frequently aberrantly expressed in cancers, and may contribute towards tumour heterogeneity and TIC behaviour. More recent efforts have focused on miRNAs as diagnostic or therapeutic targets. Here, we identified the TIC-specific miRNAs, miR-1246 and miR-1290, as crucial drivers for tumour initiation and cancer progression in human non-small cell lung cancer. The loss of either miRNA impacted the tumour-initiating potential of TICs and their ability to metastasize. Longitudinal analyses of serum miR-1246 and miR-1290 levels across time correlate their circulating levels to the clinical response of lung cancer patients who were receiving ongoing anti-neoplastic therapies. Functionally, direct inhibition of either miRNA with locked nucleic acid administered systemically, can arrest the growth of established patient-derived xenograft tumours, thus indicating that these miRNAs are clinically useful as biomarkers for tracking disease progression and as therapeutic targets.
148 citations
TL;DR: Some of the current challenges faced in clinical practice for molecular testing of EGFR, ALK, and new biomarkers such as PDL1 are highlighted and the use of next generation sequencing to recruit for molecularly stratified clinical trials is discussed.
131 citations
TL;DR: Clinical implications of tumour heterogeneity are stressed, as well as current available methodologies for their study, paying specific attention to those able to assess heterogeneity at the single cell level.
Abstract: Tumour heterogeneity refers to the fact that different tumour cells can show distinct morphological and phenotypic profiles, including cellular morphology, gene expression, metabolism, motility, proliferation and metastatic potential. This phenomenon occurs both between tumours (inter-tumour heterogeneity) and within tumours (intra-tumour heterogeneity), and it is caused by genetic and non-genetic factors. The heterogeneity of cancer cells introduces significant challenges in using molecular prognostic markers as well as for classifying patients that might benefit from specific therapies. Thus, research efforts for characterizing heterogeneity would be useful for a better understanding of the causes and progression of disease. It has been suggested that the study of heterogeneity within Circulating Tumour Cells (CTCs) could also reflect the full spectrum of mutations of the disease more accurately than a single biopsy of a primary or metastatic tumour. In previous years, many high throughput methodologies have raised for the study of heterogeneity at different levels (i.e., RNA, DNA, protein and epigenetic events). The aim of the current review is to stress clinical implications of tumour heterogeneity, as well as current available methodologies for their study, paying specific attention to those able to assess heterogeneity at the single cell level.
120 citations
TL;DR: The current status of ctDNA as a ‘liquid biopsy’ in breast cancer is reviewed and may be used to characterise tumour heterogeneity and metastasis‐specific mutations providing information to adapt the therapeutic management of patients.
102 citations
TL;DR: In this article, the single-cell mass accumulation rate (MAR) was used to predict drug response using samples as small as 25 μl of peripheral blood while maintaining cell viability and compatibility with downstream characterization.
Abstract: Assays that can determine the response of tumor cells to cancer therapeutics could greatly aid the selection of drug regimens for individual patients. However, the utility of current functional assays is limited, and predictive genetic biomarkers are available for only a small fraction of cancer therapies. We found that the single-cell mass accumulation rate (MAR), profiled over many hours with a suspended microchannel resonator, accurately defined the drug sensitivity or resistance of glioblastoma and B-cell acute lymphocytic leukemia cells. MAR revealed heterogeneity in drug sensitivity not only between different tumors, but also within individual tumors and tumor-derived cell lines. MAR measurement predicted drug response using samples as small as 25 μl of peripheral blood while maintaining cell viability and compatibility with downstream characterization. MAR measurement is a promising approach for directly assaying single-cell therapeutic responses and for identifying cellular subpopulations with phenotypic resistance in heterogeneous tumors.
91 citations
TL;DR: Understanding how cancer genetics synergize with the emerging non‐genetic factors will be key for development of therapies able to tackle tumour escape and thereby improve cancer patient survival is believed to be key.
Abstract: Cancer patients die primarily due to disease recurrence after transient treatment responses. The emergence of therapy-resistant escape variants is fuelled by intra-tumour heterogeneity, underpinned by interference and Darwinian evolution among continuously developing sub-clones in the mutating tumour. Novel cancer cell variants build upon the pre-existing genetic landscape and tumour heterogeneity is often ascribed largely to genetic variability. While mutations are required for cancer development and studies of genetic evolution of tumours have improved our understanding of cancer biology, genetics only represents one dimension of the fitness of each cancer cell. Beyond the mutations, several non-genetic factors also add significant variability, resulting in a complex and highly dynamic tumour cell population that can drive disease under almost any condition. This viewpoint article summarizes the genetic basis of intra-tumour heterogeneity, before dissecting four major interdependent non-genetic factors we think critically contribute to the overall variability of tumour cells in all types of cancer: epigenetic regulation, cellular differentiation hierarchies, gene expression stochasticity and tumour microenvironment. We finally present the relevant technological approaches to address the combined contribution of both genetic and non-genetic factors to intra-tumour heterogeneity, focusing on genomic profiling, cellular lineage tracing and single-cell RNA sequencing technologies. This strategy will ultimately allow dissection of the full range and depth of intra-tumour heterogeneity. We thus believe that understanding how cancer genetics synergize with the emerging non-genetic factors will be key for development of therapies able to tackle tumour escape and thereby improve cancer patient survival.
TL;DR: The biochemical features of KLKs, their functional roles in carcinogenesis, followed by the latest developments and the successful utility of KL kallikrein-based therapeutics in counteracting cancer progression are reviewed.
TL;DR: The biological imaging features defined in NSCLC tumours showed large interpatient and intratumour variability and there was overlap between hypoxic and metabolically active subvolumes in the majority of tumours.
Abstract: Purpose
Multiple imaging techniques are nowadays available for clinical in-vivo visualization of tumour biology. FDG PET/CT identifies increased tumour metabolism, hypoxia PET visualizes tumour oxygenation and dynamic contrast-enhanced (DCE) CT characterizes vasculature and morphology. We explored the relationships among these biological features in patients with non-small-cell lung cancer (NSCLC) at both the patient level and the tumour subvolume level.
TL;DR: The results unveil an unsuspected role of the PAF-Wnt signalling axis in modulating cell plasticity, which is required for the maintenance of breast cancer cell stemness.
Abstract: Cancer stem cells (CSCs) contribute to tumour heterogeneity, therapy resistance and metastasis. However, the regulatory mechanisms of cancer cell stemness remain elusive. Here we identify PCNA-associated factor (PAF) as a key molecule that controls cancer cell stemness. PAF is highly expressed in breast cancer cells but not in mammary epithelial cells (MECs). In MECs, ectopic expression of PAF induces anchorage-independent cell growth and breast CSC marker expression. In mouse models, conditional PAF expression induces mammary ductal hyperplasia. Moreover, PAF expression endows MECs with a self-renewing capacity and cell heterogeneity generation via Wnt signalling. Conversely, ablation of endogenous PAF induces the loss of breast cancer cell stemness. Further cancer drug repurposing approaches reveal that NVP-AUY922 downregulates PAF and decreases breast cancer cell stemness. Our results unveil an unsuspected role of the PAF-Wnt signalling axis in modulating cell plasticity, which is required for the maintenance of breast cancer cell stemness.
TL;DR: Comparing whole-genome sequencing of tumour/normal pairs from the two time points, with coincident tumour RNA sequencing, reveals widespread spatial and temporal heterogeneity, with marked remodelling of the clonal landscape in response to NAI.
Abstract: Resistance to oestrogen-deprivation therapy is common in oestrogen-receptor-positive (ER+) breast cancer. To better understand the contributions of tumour heterogeneity and evolution to resistance, here we perform comprehensive genomic characterization of 22 primary tumours sampled before and after 4 months of neoadjuvant aromatase inhibitor (NAI) treatment. Comparing whole-genome sequencing of tumour/normal pairs from the two time points, with coincident tumour RNA sequencing, reveals widespread spatial and temporal heterogeneity, with marked remodelling of the clonal landscape in response to NAI. Two cases have genomic evidence of two independent tumours, most obviously an ER− ‘collision tumour’, which was only detected after NAI treatment of baseline ER+ disease. Many mutations are newly detected or enriched post treatment, including two ligand-binding domain mutations in ESR1. The observed clonal complexity of the ER+ breast cancer genome suggests that precision medicine approaches based on genomic analysis of a single specimen are likely insufficient to capture all clinically significant information. Aromatase inhibitors are used to treat oestrogen-receptor-positive breast cancer. Here, the authors use genomic approaches to analyse tumours before and after neo-adjuvant treatment and find that treatment alters the clonal landscape of the tumours.
TL;DR: CASCADE is described, an autopsy program that overcomes logistical challenges to enable collection of samples at end stage for research in melanoma and breast, ovarian and prostate cancers and is applicable to researchers in other large urban centers.
Abstract: To the Editor: Systematic genomic studies, including the Cancer Genome Atlas (TCGA)1 and the International Cancer Genome Consortium (ICGC)2, have provided an unprecedented catalog of driver mutations in human cancer. However, these studies use mainly primary, pre-treatment tumor material obtained at surgery with curative intent. There is an urgent need to identify and characterize resistance mechanisms to understand how cancers can evade even the best medical efforts and kill patients; therefore, access to end-stage disease is important. Solid cancers show considerable spatial3, temporal4,5 and genomic heterogeneity at diagnosis. Selective pressure and mutagenic impact of treatment6 drives intra-patient evolution of cancer cell populations4,7. Understanding acquired resistance requires access to paired preand post-treatment samples4,7; however, curative surgery is typically confined to patients with locoregional disease, and opportunities for tumor sampling in advanced disseminated disease are limited. Here, we describe Cancer Tissue Collection After Death (CASCADE), an autopsy program that overcomes logistical challenges to enable collection of samples at end stage for research in melanoma and breast, ovarian and prostate cancers. For the CASCADE study, we aimed to recruit cancer patients close to the end of life, including those outside the minority of patients who die in hospitals. To preserve tissue integrity, autopsies must commence within a few hours of death, requiring access to around-the-clock services. Intervention in the emotionally charged end-of-life environment must be managed in an ethical manner and to a high standard. Finally, we aimed for the study to be highly cost-effective. We believe our approach to meeting these challenges is applicable to researchers in other large urban centers. Here we summarize the main steps in CASCADE’s operating protocol and our experiences from the initial 3 years and 30 autopsies performed (Fig. 1). Information about institutional review board approvals (including a detailed patient informationand-consent form), the autopsy procedure and certain laboratory processes is given in Supplementary Methods and Supplementary Figure 1. Recruitment of participants was led by the clinicians. Such discussions require careful consideration, in timing and in language, and were initiated only if there was a perception that tissue donation would be acceptable to the patients and their families. Factors suggesting acceptability include the emotional stability of the participant and family members and their clarity about and acceptance of the terminal nature of the disease. On occasion, participants prompted discussion by asking about organ or body donation. Consent discussions typically involved oncologists and/or palliative care physicians employed at recruiting hospitals who had established a care relationship with the participant and their family during the patient’s cancer journey. Frequently, the study was introduced at one meeting and discussed over several subsequent clinic visits, allowing patients and their families time to consider participation. We view the involvement of family members in the consent process as essential to support the participant and facilitate decisionmaking. Involvement of family members also ensures that they are fully aware of the autopsy process and helps to clarify funeral arrangements for the study team. After obtaining consent, study investigators collated clinical information, including that related to past and current treatment and diagnostic procedures such as imaging, on an ongoing basis. Between September 2012 and August 2015, 40 patients were approached, and 37 (92.5%) expressed interest in participating. Of those 32 patients (80%) consented; the other 5 had rapid clinical deterioration precluding
TL;DR: Advances in understanding of 'omics' level knowledge are summarized, and the remaining challenges surrounding tumour heterogeneity and the ability to overcome treatment resistance are described.
Abstract: Over the past several years, analyses of data from high-throughput studies have elucidated many fundamental insights into prostate cancer biology. These insights include the identification of molecular alterations and subtypes that drive tumour progression, recurrent aberrations in signalling pathways, the existence of substantial intertumoural and intratumoural heterogeneity, Darwinian evolution in response to therapeutic pressures and the complicated multidirectional patterns of spread between primary tumours and metastatic sites. However, these concepts have not yet been fully translated into clinical tools to improve prognostication, prediction and personalization of treatment of patients with prostate cancer. The current and future clinical implications of 'omics' level knowledge is not only revolutionizing our understanding of prostate cancer biology, but is also shaping ongoing, and future clinical investigations and practice. In this Review, we summarize these advances, and the remaining challenges surrounding tumour heterogeneity and the ability to overcome treatment resistance are also described.
TL;DR: This work discusses how CSC function is affected by chromatin state and epigenomic instability and suggests these epigenetic changes could be inherently more amenable to inhibition and reversal than hard-wired genomic alterations.
TL;DR: Heterogeneity measures computed on the post-contrast pre-operative T1 weighted MR images of patients with GBM are predictors of survival, according to Kaplan-Meyer survival analysis.
Abstract: Objective:The main objective of this retrospective work was the study of three-dimensional (3D) heterogeneity measures of post-contrast pre-operative MR images acquired with T1 weighted sequences of patients with glioblastoma (GBM) as predictors of clinical outcome.Methods:79 patients from 3 hospitals were included in the study. 16 3D textural heterogeneity measures were computed including run-length matrix (RLM) features (regional heterogeneity) and co-occurrence matrix (CM) features (local heterogeneity). The significance of the results was studied using Kaplan–Meier curves and Cox proportional hazards analysis. Correlation between the variables of the study was assessed using the Spearman's correlation coefficient.Results:Kaplan–Meyer survival analysis showed that 4 of the 11 RLM features and 4 of the 5 CM features considered were robust predictors of survival. The median survival differences in the most significant cases were of over 6 months.Conclusion:Heterogeneity measures computed on the post-cont...
TL;DR: Various aspects of morphological heterogeneity in pancreatic ductal adenocarcinoma are illustrated in this article and discussed along with the possible implications for patient management and research.
TL;DR: The current understanding of the molecular characteristics of GEP-NENs is described, and how advances in molecular profiling measurements, including assays of circulating mRNAs, are likely to influence the management of these tumours are discussed.
Abstract: Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) constitute a heterogeneous group of tumours associated with variable clinical presentations, growth rates, and prognoses. To improve the management of GEP-NENs, the WHO developed a classification system that enables tumours to be graded based on markers of cell proliferation in biopsy specimens. Indeed, histopathology has been a mainstay in the diagnosis of GEP-NENs, and the WHO grading system facilitates therapeutic decision-making; however, considerable intratumoural heterogeneity, predominantly comprising regional variations in proliferation rates, complicates the evaluation of tumour biology. The use of molecular imaging modalities to delineate the most-aggressive cell populations is becoming more widespread. In addition, molecular profiling is increasingly undertaken in the clinical setting, and genomic studies have revealed a number of chromosomal alterations in GEP-NENs, although the 'drivers' of neoplastic development have not been identified. Thus, our molecular understanding of GEP-NENs remains insufficient to inform on patient prognosis or selection for treatments, and the WHO classification continues to form the basis for management of this disease. Nevertheless, our increasing understanding of the molecular genetics and biology of GEP-NENs has begun to expose flaws in the WHO classification. We describe the current understanding of the molecular characteristics of GEP-NENs, and discuss how advances in molecular profiling measurements, including assays of circulating mRNAs, are likely to influence the management of these tumours.
TL;DR: This review will focus on the dynamic interconversion and overlap between different melanoma cell phenotypes in the context of therapy resistance and a dynamically changing multicellular microenvironment.
TL;DR: Primary bladder tumours and metastatic lesions showed heterogeneity at the molecular level, but within the primary tumour the heterogeneity appeared low, and the observed lack of potential therapeutic targets common to all cancer cells in primary tumouring regions and metastases emphasizes the challenges in designing rational targeted therapy.
TL;DR: F fluorine 18 (18F)‐fluorodeoxyglucose (FDG)‐positron emission tomography (PET) value and Ki67 index are correlated to patients' survival, taking into account tumour heterogeneity, disease characteristics and genetic aberrations.
Abstract: Aims The role of tumour metabolic and proliferative indices in predicting non-small-cell lung cancer (NSCLC) patients' prognosis is unclear. We correlated fluorine 18 ((18) F)-fluorodeoxyglucose (FDG)-positron emission tomography (PET) value and Ki67 index to patients' survival, taking into account tumour heterogeneity, disease characteristics and genetic aberrations. Methods and results A series of 383 NSCLCs was arranged into tissue microarrays and Ki67 staining was analysed by immunohistochemistry. The maximum standardized uptake (SUV(MAX) ) value detected by (18) F-FDG-PET analysis was calculated over a region of interest. Large-cell and squamous cell carcinomas had higher proliferative and metabolic activities than adenocarcinomas, and the two measures were correlated significantly. The hot-spot Ki67 value was correlated with patients' survival and the cut-off to discriminate patients in the survival risk groups was 20%. Ki67 hot-spot values were greater in anaplastic lymphoma kinase (ALK) rearranged tumours. Adenocarcinomas showed the highest intratumour heterogeneity in proliferative activity and the hot-spot Ki67 value predicted only the prognosis of patients in this group. Although tumour metabolic activity was not associated with patients' prognosis, a SUV(MAX) > 2 was related to nodal metastases, tumour size and grade. Conclusions Our results highlight how tumour heterogeneity influences evaluation of prognostic biomarkers. Our data support Ki67 evaluation to estimate NSCLC patients' prognosis, particularly for adenocarcinoma.
TL;DR: A range of issues that need to be addressed when CTTA is included as part of routine clinical care as opposed to its use in a research setting are discussed.
Abstract: Patients with non-small cell lung cancer frequently demonstrate differing clinical courses, even when they express the same tumour stage. Additional markers of prognostic significance could allow further stratification of treatment for these patients. By generating quantitative information about tumour heterogeneity as reflected by the distribution of pixel values within the tumour, CT texture analysis (CTTA) can provide prognostic information for patients with NSCLC. In addition to describing the practical application of CTTA to NSCLC, this article discusses a range of issues that need to be addressed when CTTA is included as part of routine clinical care as opposed to its use in a research setting. The use of quantitative imaging to provide prognostic information is a new and exciting development within cancer imaging that can expand the imaging specialist’s existing role in tumour evaluation. Derivation of prognostic information through the application of image processing techniques such as CTTA, to images acquired as part of routine care can help imaging specialists make best use of the technologies they deploy for the benefit of patients with cancer.
TL;DR: This work presents an integrative method combining bright-field dual-colour chromogenic and silver ISH assays with an image-based computational workflow (ISHProfiler), for accurate detection of molecular signals, high-throughput evaluation of CNV, and expressive visualization of multi-level heterogeneity in diverse human tumours with unprecedented throughput and reproducibility.
Abstract: Recent large-scale genome analyses of human tissue samples have uncovered a high degree of genetic alterations and tumour heterogeneity in most tumour entities, independent of morphological phenotypes and histopathological characteristics. Assessment of genetic copy-number variation (CNV) and tumour heterogeneity by fluorescence in situ hybridization (ISH) provides additional tissue morphology at single-cell resolution, but it is labour intensive with limited throughput and high inter-observer variability. We present an integrative method combining bright-field dual-colour chromogenic and silver ISH assays with an image-based computational workflow (ISHProfiler), for accurate detection of molecular signals, high-throughput evaluation of CNV, expressive visualization of multi-level heterogeneity (cellular, inter- and intra-tumour heterogeneity), and objective quantification of heterogeneous genetic deletions (PTEN) and amplifications (19q12, HER2) in diverse human tumours (prostate, endometrial, ovarian and gastric), using various tissue sizes and different scanners, with unprecedented throughput and reproducibility.
TL;DR: The present review focuses on the heterogeneity of neoplastic disease, both within the primary tumour and between primary tumours and metastases, as well as imminent developments relevant for clinical research and diagnostic pathology.
Abstract: Two major reasons compel us to study tumour heterogeneity: firstly, it represents the basis of acquired therapy resistance, and secondly, it may be one of the major sources of the low level of reproducibility in clinical cancer research. The present review focuses on the heterogeneity of neoplastic disease, both within the primary tumour and between primary tumour and metastases. We discuss different levels of heterogeneity and the current understanding of the phenomenon, as well as imminent developments relevant for clinical research and diagnostic pathology. It is necessary to develop new tools to study heterogeneity and new biomarkers for heterogeneity. Established and new in situ methods will be very useful. In future studies, not only clonal heterogeneity needs to be addressed but also non-clonal phenotypic heterogeneity which might be important for therapy resistance. We also review heterogeneity established in major tumour types, in order to explore potential similarities that might help to define new strategies for targeted therapy.
TL;DR: It appears that although LKB1 deficiency can suppress oncogenic transformation in the short term, it can ultimately lead to more progressed and malignant phenotypes by driving abnormal cell differentiation, genomic instability and increased tumour heterogeneity.
TL;DR: Results provide a compelling rationale for the clinical development of mTOR-targeted therapies and show a preferential inhibitory effect on CSCs has already been shown for some mTOR inhibitors.
Abstract: The mammalian target of rapamycin (mTOR) pathway is aberrantly activated in many cancer types. As the intricate network of regulatory mechanisms controlling mTOR activity is uncovered, more refined drugs are designed and tested in clinical trials. While first generation mTOR inhibitors have failed to show clinical efficacy due partly to the feedback relief of oncogenetic circuits, newly developed inhibitors show greater promise as anti-cancer agents. An effective drug must defeat the cancer stem cells (CSCs) while sparing the normal stem cells. Due to its opposing role on normal and malignant stem cells, mTOR lends itself very well as a therapeutic target. Indeed, a preferential inhibitory effect on CSCs has already been shown for some mTOR inhibitors. These results provide a compelling rationale for the clinical development of mTOR-targeted therapies.
TL;DR: Recent developments in imaging technologies and the evolving roles for these techniques in colorectal cancer are reviewed.
Abstract: Imaging techniques play a key role in the management of patients with colorectal cancer. The introduction of new advanced anatomical, functional, and molecular imaging techniques may improve the assessment of diagnosis, prognosis, planning therapy, and assessment of response to treatment of these patients. Functional and molecular imaging techniques in clinical practice may allow the assessment of tumour-specific characteristics and tumour heterogeneity. This paper will review recent developments in imaging technologies and the evolving roles for these techniques in colorectal cancer. • Imaging techniques play a key role in the management of patients with colorectal cancer. • Advanced imaging techniques improve the evaluation of these patients. • Functional and molecular imaging allows assessment of tumour hallmarks and tumour heterogeneity.