Xue Gao

Bio: Xue Gao is an academic researcher from Fudan University. The author has contributed to research in topics: Hepatocellular carcinoma & Microdissection. The author has an hindex of 6, co-authored 6 publications receiving 797 citations.

Plasma MicroRNA Panel to Diagnose Hepatitis B Virus–Related Hepatocellular Carcinoma

Abstract: Purpose More than 60% of patients with hepatocellular carcinoma (HCC) do not receive curative therapy as a result of late clinical presentation and diagnosis. We aimed to identify plasma microRNAs for diagnosing hepatitis B virus (HBV) –related HCC. Patients and Methods Plasma microRNA expression was investigated with three independent cohorts including 934 participants (healthy, chronic hepatitis B, cirrhosis, and HBV-related HCC), recruited between August 2008 and June 2010. First, we used microarray to screen 723 microRNAs in 137 plasma samples for diagnosing HCC. Quantitative reverse-transcriptase polymerase chain reaction assay was then applied to evaluate the expression of selected microRNAs. A logistic regression model was constructed using a training cohort (n 407) and then validated using an independent cohort (n 390). Area under the receiver operating characteristic curve (AUC) was used to evaluate diagnostic accuracy. Results We identified a microRNA panel (miR-122, miR-192, miR-21, miR-223, miR-26a, miR-27a and miR-801) that provided a high diagnostic accuracy of HCC (AUC 0.864 and 0.888 for training and validation data set, respectively). The satisfactory diagnostic performance of the microRNA panel persisted regardless of disease status (AUCs for Barcelona Clinic Liver Cancer stages 0, A, B, and C were 0.888, 0.888, 0.901, and 0.881, respectively). The microRNA panel can also differentiate HCC from healthy (AUC 0.941), chronic hepatitis B (AUC 0.842), and cirrhosis (AUC 0.884), respectively.

A plasma microRNA panel for early detection of colorectal cancer

Abstract: Colonoscopy remains the standard screening method for detecting colorectal cancer (CRC) at an early stage. However, many people avoid having a colonoscopy because of the fear for its potential complications. Our study aimed to identify plasma microRNAs for preliminarily screening CRC in general population, so that some unnecessary colonoscopies can be avoided. We investigated plasma microRNA expression in three independent cohorts including the discovery (n = 80), training (n = 112), and validation (n = 49) phases recruited at two medical centers. Microarrays were used for screening 723 microRNAs in 80 plasma samples to identify candidate microRNAs. Quantitative reverse-transcriptase PCR was performed on the 161 training and validation plasma samples to evaluate the candidate microRNAs discovered from microarrays. A logistic regression model was constructed based on the training cohort and then verified by using the validation dataset. Area under the receiver operating characteristic curve (AUC) was used to evaluate the diagnostic accuracy. We identified a panel of miR-409-3p, miR-7, and miR-93 that yielded high diagnostic accuracy in discriminating CRC from healthy group (AUC: 0.866 and 0.897 for training and validation dataset, respectively). Moreover, the diagnostic performance of the microRNA panel persisted in nonmetastasis CRC stages (Dukes' A-B, AUC: 0.809 and 0.892 for training and validation dataset, respectively) and in metastasis CRC stages (Dukes' C-D, AUC: 0.917 and 0.865 for training and validation dataset, respectively). In conclusion, our study reveals a plasma microRNA panel that has potential clinical value in early CRC detection and would play a critical role on preliminarily screening CRC in general population.

Human miR-1228 as a stable endogenous control for the quantification of circulating microRNAs in cancer patients.

Abstract: Circulating microRNAs are promising biomarkers for non-invasive testing and dynamic monitoring in cancer patients However, no consensus exists regarding the normalization of circulating microRNAs in the quantification, making the results incomparable We investigated global circulating microRNA profiles to identify a stable endogenous control for quantifying circulating microRNAs using three cohorts (n = 544), including 168 control individuals (healthy subjects and those with chronic hepatitis B and cirrhosis) and 376 cancer patients (hepatocellular, colorectal, lung, esophageal, gastric, renal, prostate, and breast cancer patients) GeNorm, NormFinder, and coefficient of variability (CV) were used to select the most stable endogenous control, whereas Ingenuity Pathway Analysis (IPA) was adopted to explore its signaling pathways Seven candidates (miR-1225-3p, miR-1228, miR-30d, miR-939, miR-940, miR-188-5p, and miR-134) from microarray analysis and four commonly used controls (miR-16, miR-223, let-7a, and RNU6B) from literature were subjected to real-time quantitative reverse transcription-polymerase chain reaction validation using independent cohorts MiR-1228 (CV = 54%) with minimum M value and S value presented as the most stable endogenous control across eight cancer types and three controls IPA showed miR-1228 to be involved extensively in metabolism-related signal pathways and organ morphology, implying that miR-1228 functions as a housekeeping gene Functional network analysis found that "hematological system development" was on the list of the top networks that associate with miR-1228, implying that miR-1228 plays an important role in the hematological system The results explained the steady expression of miR-1228 in the blood In conclusion, miR-1228 is a promising stable endogenous control for quantifying circulating microRNAs in cancer patients

Improvement of tissue preparation for laser capture microdissection: application for cell type-specific miRNA expression profiling in colorectal tumors

Abstract: Laser capture microdissection (LCM) has successfully isolated pure cell populations from tissue sections and the combination of LCM with standard genomic and proteomic methods has revolutionized molecular analysis of complex tissue. However, the quantity and quality of material recovered after LCM is often still limited for analysis by using whole genomic and proteomic approaches. To procure high quality and quantity of RNA after LCM, we optimized the procedures on tissue preparations and applied the approach for cell type-specific miRNA expression profiling in colorectal tumors. We found that the ethanol fixation of tissue sections for 2 hours had the maximum improvement of RNA quality (1.8 fold, p = 0.0014) and quantity (1.5 fold, p = 0.066). Overall, the quality (RNA integrity number, RIN) for the microdissected colorectal tissues was 5.2 ± 1.5 (average ± SD) for normal (n = 43), 5.7 ± 1.1 for adenomas (n = 14) and 7.2 ± 1.2 for carcinomas (n = 44). We then compared miRNA expression profiles of 18 colorectal tissues (6 normal, 6 adenomas and 6 carcinomas) between LCM selected epithelial cells versus stromal cells using Agilent miRNA microarrays. We identified 51 differentially expressed miRNAs (p <= 0.001) between these two cell types. We found that the miRNAs in the epithelial cells could differentiate adenomas from normal and carcinomas. However, the miRNAs in the stromal and mixed cells could not separate adenomas from normal tissues. Finally, we applied quantitative RT-PCR to cross-verify the expression patterns of 7 different miRNAs using 8 LCM-selected epithelial cells and found the excellent correlation of the fold changes between the two platforms (R = 0.996). Our study demonstrates the feasibility and potential power of discovering cell type-specific miRNA biomarkers in complex tissue using combination of LCM with genome-wide miRNA analysis.

A microRNA panel to discriminate carcinomas from high-grade intraepithelial neoplasms in colonoscopy biopsy tissue

Abstract: Objective It is a challenge to differentiate invasive carcinomas from high-grade intraepithelial neoplasms in colonoscopy biopsy tissues. In this study, microRNA profiles were evaluated in the transformation of colorectal carcinogenesis to discover new molecular markers for identifying a carcinoma in colonoscopy biopsy tissues where the presence of stromal invasion cells is not detectable by microscopic analysis. Methods The expression of 723 human microRNAs was measured in laser capture microdissected epithelial tumours from 133 snap-frozen surgical colorectal specimens. Three well-known classification algorithms were used to derive candidate biomarkers for discriminating carcinomas from adenomas. Quantitative reverse-transcriptase PCR was then used to validate the candidates in an independent cohort of macrodissected formalin-fixed paraffin-embedded colorectal tissue samples from 91 surgical resections. The biomarkers were applied to differentiate carcinomas from high-grade intraepithelial neoplasms in 58 colonoscopy biopsy tissue samples with stromal invasion cells undetectable by microscopy. Results One classifier of 14 microRNAs was identified with a prediction accuracy of 94.1% for discriminating carcinomas from adenomas. In formalin-fixed paraffin-embedded surgical tissue samples, a combination of miR-375, miR-424 and miR-92a yielded an accuracy of 94% (AUC=0.968) in discriminating carcinomas from adenomas. This combination has been applied to differentiate carcinomas from high-grade intraepithelial neoplasms in colonoscopy biopsy tissues with an accuracy of 89% (AUC=0.918). Conclusions This study has found a microRNA panel that accurately discriminates carcinomas from high-grade intraepithelial neoplasms in colonoscopy biopsy tissues. This microRNA panel has considerable clinical value in the early diagnosis and optimal surgical decision-making of colorectal cancer.

MicroRNA profiling: approaches and considerations.

Abstract: MicroRNAs (miRNAs) are small RNAs that post-transcriptionally regulate the expression of thousands of genes in a broad range of organisms in both normal physiological contexts and in disease contexts. miRNA expression profiling is gaining popularity because miRNAs, as key regulators in gene expression networks, can influence many biological processes and also show promise as biomarkers for disease. Technological advances have spawned a multitude of platforms for miRNA profiling, and an understanding of the strengths and pitfalls of different approaches can aid in their effective use. Here, we review the major considerations for carrying out and interpreting results of miRNA-profiling studies.

Clinical relevance of circulating cell-free microRNAs in cancer

Abstract: Efficient patient management relies on early diagnosis of disease and monitoring of treatment. In this regard, much effort has been made to find informative, blood-based biomarkers for patients with cancer. Owing to their attributes-which are specifically modulated by the tumour-circulating cell-free microRNAs found in the peripheral blood of patients with cancer may provide insights into the biology of the tumour and the effects of therapeutic interventions. Moreover, the role of microRNAs in the regulation of different cellular processes points to their clinical utility as blood-based biomarkers and future therapeutic targets. MicroRNAs are optimal biomarkers owing to high stability under storage and handling conditions and their presence in blood, urine and other body fluids. In particular, detection of levels of microRNAs in blood plasma and serum has the potential for an earlier cancer diagnosis and to predict prognosis and response to therapy. This Review article considers the latest developments in the use of circulating microRNAs as prognostic and predictive biomarkers and discusses their utility in personalized medicine.

MicroRNAs: Target Recognition and Regulatory Functions

Abstract: MicroRNAs (miRNAs) are endogenous ∼23 nt RNAs that play important gene-regulatory roles in animals and plants by pairing to the mRNAs of protein-coding genes to direct their posttranscriptional repression. This review outlines the current understanding of miRNA target recognition in animals and discusses the widespread impact of miRNAs on both the expression and evolution of protein-coding genes.