We reviewed the current evidence for three novel prostate tumor markers (PCA3, TMPRSS2:ERG and proPSA) that have been recently reported predominantly in Western countries. We focus our attention on Asian men in both clinical and basic research studies. There have been no reports on the clinical usefulness of these three markers for Asians living in Western countries. In Asian countries, evidence for the clinical usefulness of PCA3 and proPSA-related indices including Prostate Health Index is being accumulated, mainly in Japan. The process for how a novel marker is approved in the clinical setting is also discussed.

Introduction Several prostate cancers carry homologous recombination repair mutations that respond to olaparib. Because of the mechanism, the efficacy of platinum‐based therapy can be used to predict the efficacy of poly(adenosine diphosphate‐ribose) polymerase inhibitors such as olaparib. Case presentation We experienced two neuroendocrine prostate cancer patients who achieved a response duration of more than 1 year with platinum‐based therapy. Case 1 had a BRCA2 mutation in the germline and case 2 had a BRCA2 mutation in a somatic chromosome only. Both patients responded well to olaparib. Conclusion Cisplatin and olaparib may overlap in response due to their medicinal action. It may be useful to consider genetic testing in some CRPC patients who have responded to cisplatin.

Japan has experienced a drastic increase in the incidence of prostate cancer (PC). To assess changes in the risk for PC, we investigated baseline prostate specific antigen (PSA) levels in first-time screened men, across a 25-year period. In total, 72,654 men, aged 50-79, underwent first-time PSA screening in Gunma prefecture between 1992 and 2016. Changes in the distribution of PSA levels were investigated, including the percentage of men with a PSA above cut-off values and linear regression analyses comparing log PSA with age. The 'ultimate incidence' of PC and clinically significant PC (CSPC) were estimated using the PC risk calculator. Changes in the age-standardized incidence rate (AIR) during this period were analyzed. The calculated coefficients of linear regression for age versus log PSA fluctuated during the 25-year period, but no trend was observed. In addition, the percentage of men with a PSA above cut-off values varied in each 5-year period, with no specific trend. The 'risk calculator (RC)-based AIR' of PC and CSPC were stable between 1992 and 2016. Therefore, the baseline risk for developing PC has remained unchanged in the past 25 years, in Japan. The drastic increase in the incidence of PC, beginning around 2000, may be primarily due to increased PSA screening in the country.

Free to total prostate-specific antigen ratio in men with low baseline prostate-specific antigen levels seems to predict the risk of developing prostate cancer, and it could be useful for a more effective individualized screening system. Longitudinal changes in [-2] proenzyme prostate-specific antigen-related indices seem to correlate with tumor aggressiveness, and they could be used as prognostic tool before treatment and during active surveillance.

An urgent need exists to develop a more sophisticated screening system in order to improve diagnostic accuracy of clinically significant cancer and also to reduce the drawbacks of prostate-specific antigen (PSA) screening including overdetection and overtreatment. The most promising next-generation PSA test, which can improve the management of prostate cancer, may be proenzyme PSA (proPSA) or precursor PSA (pPSA). proPSA has pro-leader peptide sequences of seven or less amino acids and previous studies demonstrated that [-2]proPSA, which contains only a 2-amino-acid propeptide leader, could be more useful not only to distinguish between men with and without cancer, but also between tumors with aggressive features with performance exceeding other classical PSA-related indices including ratio of free PSA to total PSA (%f-PSA) and PSA density. Recently, it was demonstrated that baseline [-2]proPSA-related indices were independent factors to predict pathological reclassification at one year or several years after entering active surveillance. Furthermore, a retrospective study suggested that [-2]proPSA might be a useful predictive marker for future developing clinically manifested prostate cancer as well as aggressive tumors. ProPSA-related indices may have the potential for developing a more ideal risk classification for men at risk for prostate cancer, with a screening system maintaining the sensitivity of detecting clinically significant prostate cancer while saving cost, individualized treatment strategies, and follow-up procedures of active surveillance or active treatments. At a minimum, proPSA will be one of the most important new markers on the prostate cancer management in the near future.