Abstract 5033: Relationship between microRNA expression and Gleason grading system in prostate cancer

The Gleason grading system for prostatic carcinoma is widely used internationally and is based on microscopic architectural patterns of tumors. Over the years, there have been modifications to the original grading system established by Donald F Gleason in 1966 and refined in 1974 which have subsequently been established by the World Health Organization in its WHO Classification of Tumors of the Urinary System and Male Genital Organs book, published in 2016. There have been certain practical issues associated with the changes, of note, the addition of intraductal carcinoma of prostate (IDC-P), which unlike its breast counterpart rarely occurs in isolation without association with invasive carcinoma and tends to be associated with high-grade invasive carcinoma. In addition, the Grade group system has been introduced which categorizes tumors into prognostically relevant groups based on the histological grade scores. The grade group system brings to light the importance of making accurate scoring and subsequent grouping of the tumors as it affects the clinical treatment, prognostic implication and stage assignment. Molecular pathology of the prostate is not widely utilized in clinical practice, but is emerging. The most common genomic aberration in prostate cancer includes gene fusion, amplification, deletion, and mutation. In addition, up and down regulation of gene expression in critical cellular pathways is also at play. A series of long noncoding RNA expression changes have been also unveiled from transcriptome sequencing data. They play a regulatory role in prostate cancer and are promising diagnostic and potentially prognostic markers as well as molecular treatment strategy. In this review, we summarize recent advances in molecular pathology of prostate cancer and their emerging clinical utility with currently available molecular tests. In this review article, we discuss the followings: 1) Gleason grading system with its modification, 2) Grade group, 3) Intraductal carcinoma, and 4) molecular pathology. Additionally, we present that molecular studies continue to emerge, and there is significant opportunity for targeted therapeutic options that remains to be explored in depth.

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Performance of a validated urine exosome gene expression assay to predict high-grade prostate cancer utilizing the International Society of Urological Pathology (ISUP) 2014 grading system.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.6_suppl.49 ◽

2017 ◽

Vol 35 (6_suppl) ◽

pp. 49-49 ◽

Cited By ~ 1

Author(s):

Michael Donovan ◽

Phillipp Torkler ◽

Johan Skog ◽

Mikkel Noerholm ◽

Peter Carroll

Keyword(s):

Gene Expression ◽

Prostate Cancer ◽

International Society ◽

Grading System ◽

Low Grade ◽

High Grade ◽

Cut Points ◽

Combined Training ◽

Gleason Grading ◽

Gene Expression Assay

49 Background: Overdetection and overtreatment of indolent prostate cancer (PCa) remains a significant health issue requiring noninvasive assays to guide the prostate biopsy decision process. We demonstrated that a urine exosome gene expression assay (ExoDx P rostate ( I ntelliScore) (EPI) discriminates GS 7 PCa from GS 6 and benign disease, potentially reducing the number of unnecessary biopsies. The International Society of Urological Pathology (ISUP) proposed a prognostic PCa grading system to accurately reflect the biology of PCa; ISUP separates GS 7 PCa into group 2 (GS 3+4) and group 3 (GS 4+3). We sought to evaluate the performance of the EPI test according to the newly proposed ISUP system. Methods: The 519 patient validation cohort was re-annotated using ISUP and assessed benign (B) +/- ISUP 1 and B+ISUP 1+2 (GS 3+3, GS 3+4) from ISUP 3-5 (GS >= 4+3). We used validated / adjusted cut-points to assess performance with the AUC, sensitivity, specificity and NPV. In addition, we investigated the association of the EPI score with the benign biopsies (BB) and ISUP groups in the combined training and test cohort (n=774). Results: Applying the adjusted cut point (EPI 20) on the 519 ISUP cohort discriminated benign biopsies (BB) + ISUP 1 from >/=ISUP 2, 37% of biopsies avoided, NPV of 90%, equivalent to Gleason grading. Utilizing either the validated (15.6) or adjusted cut points on BB+ISUP 1+ 2 vs. >/=ISUP 3 (dominant pattern 4), 26% vs 37% biopsies avoided, with an improved NPV 98%. In the combined training / test cohort, higher EPI scores were significantly associated with ISUP categories. In this analysis EPI in BB vs. all ISUP groups (p<0.0001); BB+ISUP 1 vs. >/= ISUP2 (p<0.0001) and BB+ISUP 1+2 vs. >/=ISUP3 (p<0.0001); supporting accurate discrimination in high grade PCa. Conclusions: The EPI test is a noninvasive, first-catch non-DRE gene expression assay that accurately discriminates low-grade from high-grade PCa in both ISUP as well as Gleason score based grading systems. The test has the potential to reduce the number of unnecessary biopsies and performs equally well in contemporary approaches to PCa stratification.

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