The role of treatment modality on the utility of predictive tissue biomarkers in clinical prostate cancer: a systematic review

Abstract

Despite years of research, very few tissue biomarkers retain predictive value in independent validation across therapy context. Currently, none have conclusive ability to help treatment selection. Future biomarker research should consider the therapy context and use uniform methodology and evaluation criteria.

Multi-transcript profiling in archival diagnostic prostate cancer needle biopsies to evaluate biomarkers in non-surgically treated men

“…Candidate biomarkers were identified from a recent systematic review and had shown prognostic value in surgical cohorts but had not been tested in other therapies: E Cadherin, EGFR, EZH2, PTEN and MSMB [3]. These markers are also exemplars of biological events that are critical to prostate cancer progression (metastasis, growth factor signalling, transcription factor, cell survival and inhibitor of prostate cancer growth).…”

“…The prostate marker PSMA which has shown promise as a prognostic marker following surgery but has not been tested in other treatment cohorts [8, 9]. We also included the androgen receptor (AR) which has not been tested in EBRT therapy as well as the generic marker prostate cancer antigen 3 (PCA3) [3, 10, 11]. All three were also selected as they are very well described genes expressed in prostate tissue and in prostate cancer.…”

“…There is currently no way of accurately predicting which therapy is best for an individual patient who may be otherwise eligible for both modalities [2, 3]. Tissue biomarkers that can predict and discriminate therapy outcome would therefore be an important and clinically useful tool.…”

“…A critical issue with prostate cancer biomarker research is the amount of tissue available for analysis in non-surgically treated patients. As a result, the vast majority of biomarkers have only been tested and validated in surgically treated men [3]. For non-surgical therapies however the diagnostic needle biopsy is commonly the only tissue available to investigate potential biomarkers.…”

“…In addition, we have recently undertaken a detailed systematic analysis of the available literature on tissue biomarkers within different therapy contexts [3]. This work has shown that there is a significant gap in the evidence for the usefulness of surgical biomarkers in other therapy contexts.…”