When digging further into these subtypes, researchers found they do not necessarily function as prognostic signifiers, but there is a distinct biology driving the different tumors, Cooperberg noted. Among Cluster 2, the luminal B-like tumors, these tumors had a slightly higher tumor volume and lower PSAs, whereas Cluster 3, the luminal A-like tumors, had slightly lower tumor volume and higher PSAs (Table). According to Cooperberg, these subtypes seem to be driven by androgen response elements in particular. However, he noted that there were no major differences in the clinical risk stratification between these subtypes.
Table. Characteristics of Prostate Cancer Clusters
These classifications in prostate cancer are in line with breast cancer subtypes, as was recently acknowledged in a paper published in JAMA Oncology
This study found further associations with these subtypes, including increased androgen receptor expression in both luminal subtypes. There was an association with poor outcomes among those with luminal B-like prostate cancer compared with the other subtypes.
“We found substantial—and frankly, somewhat surprising—genomic diversity among these cancers, which clinically, histologically, and pathologically have always looked homogenous. I think the prostate cancer cases we are currently seeing across different cohort studies classify in ways that, in many respects, look like other cancer types,” Cooperberg said.
This research, including Cooperberg’s conclusions for this study, may be building toward a clinical molecular taxonomy for cancer that goes beyond the organ of origin to a more biologic description of why the cancer originated and how best to treat it. This could help drive further improvements in management decision making, both in terms of who should be treated and how treating urologists can tailor therapy and surveillance protocols.
- Cooperberg MR, Erho N, Chan JM, et al. The diverse genomic landscape of low-risk prostate cancer. Abstract presented at: 2017 American Urological Association Annual Meeting; May 12-16, 2017; Boston, MA. Abstract PNFBA-09. jurology.com/article/S0022-5347(17)34704-3/pdf.
- Prostate cancer risk assessment and the UCSF-CAPRA score. UCSF Department of Urology. urology.ucsf.edu/research/cancer/prostate-cancer-risk-assessment-and-the-ucsf-capra-score. Accessed July 7, 2017.
- Zhao SG, Chang SL, Erho N, et al. Associations of luminal and basal subtyping of prostate cancer with prognosis and response to androgen deprivation therapy [published online May 11, 2017]. JAMA Oncol. doi: 10.1001/jamaoncol.2017.0751.