Recent work has revealed the existence of a class of small non-coding RNA species, known as microRNAs (miRNAs), which have critical functions across various biological processes. Here we use a new, bead-based flow cytometric miRNA expression profiling method to present a systematic expression analysis of 217 mammalian miRNAs from 334 samples, including multiple human cancers. The miRNA profiles are surprisingly informative, reflecting the developmental lineage and differentiation state of the tumours. We observe a general downregulation of miRNAs in tumours compared with normal tissues. Furthermore, we were able to successfully classify poorly differentiated tumours using miRNA expression profiles, whereas messenger RNA profiles were highly inaccurate when applied to the same samples. These findings highlight the potential of miRNA profiling in cancer diagnosis.

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MicroRNA expression profiles classify human cancers

The Epithelial-Mesenchymal Transition Generates Cells with Properties of Stem Cells

METHODS In this phase 3, open-label study, we randomly assigned previously untreated patients in East Asia who had advanced pulmonary adenocarcinoma and who were nonsmokers or former light smokers to receive gefitinib (250 mg per day) (609 patients) or carboplatin (at a dose calculated to produce an area under the curve of 5 or 6 mg per milliliter per minute) plus paclitaxel (200 mg per square meter of body-surface area) (608 patients). The primary end point was progression-free survival. RESULTS The 12-month rates of progression-free survival were 24.9% with gefitinib and 6.7% with carboplatin–paclitaxel. The study met its primary objective of showing the noninferiority of gefitinib and also showed its superiority, as compared with carboplatin– paclitaxel, with respect to progression-free survival in the intention-to-treat population (hazard ratio for progression or death, 0.74; 95% confidence interval [CI], 0.65 to 0.85; P<0.001). In the subgroup of 261 patients who were positive for the epidermal growth factor receptor gene (EGFR) mutation, progression-free survival was significantly longer among those who received gefitinib than among those who received carboplatin–paclitaxel (hazard ratio for progression or death, 0.48; 95% CI, 0.36 to 0.64; P<0.001), whereas in the subgroup of 176 patients who were negative for the mutation, progression-free survival was significantly longer among those who received carboplatin–paclitaxel (hazard ratio for progression or death with gefitinib, 2.85; 95% CI, 2.05 to 3.98; P<0.001). The most common adverse events were rash or acne (in 66.2% of patients) and diarrhea (46.6%) in the gefitinib group and neurotoxic effects (69.9%), neutropenia (67.1%), and alopecia (58.4%) in the carboplatin–paclitaxel group. CONCLUSIONS Gefitinib is superior to carboplatin–paclitaxel as an initial treatment for pulmonary adenocarcinoma among nonsmokers or former light smokers in East Asia. The presence in the tumor of a mutation of the EGFR gene is a strong predictor of a better outcome with gefitinib. (ClinicalTrials.gov number, NCT00322452.)

https://www.nejm.org/doi/pdf/10.1056/NEJMoa0810699

Gefitinib or Carboplatin–Paclitaxel in Pulmonary Adenocarcinoma

The cancer stem cell (CSC) hypothesis suggests that neoplastic clones are maintained exclusively by a rare fraction of cells with stem cell properties. Although the existence of CSCs in human leukaemia is established, little evidence exists for CSCs in solid tumours, except for breast cancer. Recently, we prospectively isolated a CD133+ cell subpopulation from human brain tumours that exhibited stem cell properties in vitro. However, the true measures of CSCs are their capacity for self renewal and exact recapitulation of the original tumour. Here we report the development of a xenograft assay that identified human brain tumour initiating cells that initiate tumours in vivo. Only the CD133+ brain tumour fraction contains cells that are capable of tumour initiation in NOD-SCID (non-obese diabetic, severe combined immunodeficient) mouse brains. Injection of as few as 100 CD133+ cells produced a tumour that could be serially transplanted and was a phenocopy of the patient's original tumour, whereas injection of 10(5) CD133- cells engrafted but did not cause a tumour. Thus, the identification of brain tumour initiating cells provides insights into human brain tumour pathogenesis, giving strong support for the CSC hypothesis as the basis for many solid tumours, and establishes a previously unidentified cellular target for more effective cancer therapies.

Identification of human brain tumour initiating cells

Because most colorectal carcinomas appear to arise from adenomas, studies of different stages of colorectal neoplasia may shed light on the genetic alterations involved in tumor progression. We looked for four genetic alterations (ras-gene mutations and allelic deletions of chromosomes 5, 17, and 18) in 172 colorectal-tumor specimens representing various stages of neoplastic development. The specimens consisted of 40 predominantly early-stage adenomas from 7 patients with familial adenomatous polyposis, 40 adenomas (19 without associated foci of carcinoma and 21 with such foci) from 33 patients without familial polyposis, and 92 carcinomas resected from 89 patients. We found that ras-gene mutations occurred in 58 percent of adenomas larger than 1 cm and in 47 percent of carcinomas. However, ras mutations were found in only 9 percent of adenomas under 1 cm in size. Sequences on chromosome 5 that are linked to the gene for familial adenomatous polyposis were not lost in adenomas from the patients with polyposis but were lost in 29 to 35 percent of adenomas and carcinomas, respectively, from other patients. A specific region of chromosome 18 was deleted frequently in carcinomas (73 percent) and in advanced adenomas (47 percent) but only occasionally in earlier-stage adenomas (11 to 13 percent). Chromosome 17p sequences were usually lost only in carcinomas (75 percent). The four molecular alterations accumulated in a fashion that paralleled the clinical progression of tumors. These results are consistent with a model of colorectal tumorigenesis in which the steps required for the development of cancer often involve the mutational activation of an oncogene coupled with the loss of several genes that normally suppress tumorigenesis.

Genetic alterations during colorectal-tumor development.

Extracellular vesicles (EVs) are nanosized vesicles secreted by virtually all cell types into the extracellular milieu. EVs transport bioactive molecules between cells and play multifaceted roles in cell-to-cell communications and in the pathogenesis of various human diseases including cancer. EVs are currently a focus of intensive interest, mainly because they hold a wealth of biological information in the form of differentially expressed nucleic acids and proteins, including DNA and cancer-related mutated genes, microRNAs, and a variety of transcriptional factors. Both the mutational content and any differentially expressed RNA are highly stable in patient blood or urine because they are encapsulated in EVs. This protects them against nuclease activity, pH change, temperature fluctuations, and multiple free-thaw cycles. Therefore, EVs isolated from patient fluids may serve as an ideal source of liquid biopsy for mining cancer signatures through mutation screening and genetic profiling. However, the methods for obtaining pure and intact EVs from patient samples, as well as the optimized characterization of tumor-derived EVs are still not rigorously defined for routine clinical use. High-throughput genomic or proteomic platforms may aid in the identification of novel diagnostic and prognostic biomarkers that collectively could lead to cancer monitoring and improved patient outcome.

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Mining Extracellular Vesicles for Clinically Relevant Noninvasive Diagnostic Biomarkers in Cancer

Introduction: Multitarget FISH (mFISH) is a technique allowing for simultaneous detection of multiple targets sequences on the same slide through the choice of spectrally distinct fluorophore label...

Multitarget fluorescence in situ hybridization diagnostic applications in solid and hematological tumors

Mp1-17 pten status determination in prostate cancer: comparison of ihc and fish in a large multi-center cohort

PTEN loss occurs in 20-30% prostate cancers (PCa), is associated with worse outcome, and regulates the type I interferon response through the interferon regulatory factor 3 (IRF3). Both PTEN loss and the overexpression of the androgen receptor (AR) promote castrate-resistant PCa leading to a more aggressive disease. To characterize the associations between PTEN loss and AR expression in immune cell infiltration in the tumor microenvironment (TME), we conducted an in silico analysis in two PCa cohorts. RNAseq and gene expression array data were imputed in CIBERSORT to evaluate the relative frequency of 22 immune infiltrating cells in the TME. PTEN was lost in 19.7% (97/491) and 19.8% (26/131) in the TCGA and MSKCC cohorts, respectively. AR was overexpressed in 56% (279/491) and 54% (71/131) of the TCGA and MSKCC cohorts, respectively. Remarkably, AR overexpression was associated with decreased CD8+ T-cells infiltration in both the TCGA (p Citation Format: Thiago Vidotto, Madhuri Koti, Jeremy A. Squire. In silico analysis shows that PTEN loss and AR overexpression are associated with increased CD8+ T-cell and Treg density and earlier disease recurrence in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5736.

Abstract 5736: In silico analysis shows that PTEN loss and AR overexpression are associated with increased CD8+ T-cell and Treg density and earlier disease recurrence in prostate cancer

Jeremy A. Squire

Papers

Mining Extracellular Vesicles for Clinically Relevant Noninvasive Diagnostic Biomarkers in Cancer

Multitarget fluorescence in situ hybridization diagnostic applications in solid and hematological tumors

Mp1-17 pten status determination in prostate cancer: comparison of ihc and fish in a large multi-center cohort

Abstract 5736: In silico analysis shows that PTEN loss and AR overexpression are associated with increased CD8+ T-cell and Treg density and earlier disease recurrence in prostate cancer

654: Telomere Length Analysis of High-Grade Prostatic Intrapeithelial Neoplasia and Surrounding Stroma Predicts Outcome to Prostate Cancer