Robert Dreicer, MD, MS, FACP, FASCO reviewing Zhao SG et al. JAMA Oncol 2017 May 11. Abida W and Scher HI. JAMA Oncol 2017 May 11.

Patients with luminal B tumors respond better to postoperative androgen-deprivation therapy than do those with non–luminal B tumors.

Although a number of gene-signature prognostic assays are on the market, their ultimate role in subtyping prostate cancer remains undefined.

Now, investigators have conducted a retrospective analysis using the commercially available PAM50 classifier to subtype 3782 prostate cancer samples, of which 1567 were collected from 6 retrospective cohorts with a median follow-up of 10 years. Samples were classified into luminal A, luminal B, and basal (34%, 29%, and 37%, respectively, in the retrospective group, and 33%, 33%, and 34% in the prospective group). Analysis of the retrospective cohort showed that the luminal B subtype was associated with a higher degree of adverse clinical features and worse clinical outcomes compared with luminal A or basal subtypes.

Given the importance of androgen-receptor signaling in prostate cancer, the researchers conducted an exploratory analysis (median follow-up, 13 years) involving a subcohort of 315 prostatectomy patients, 210 of whom had not received androgen-deprivation therapy (ADT), but who were otherwise matched for clinicopathologic factors and postoperative radiotherapy. Applying the classifier, the investigators demonstrated that luminal B patients benefitted from postoperative ADT, while luminal A and basal patients did not.

CITATION(S):

Zhao SG et al. Associations of luminal and basal subtyping of prostate cancer with prognosis and response to androgen deprivation therapy. JAMA Oncol 2017 May 11; [e-pub]. 

Abida W and Scher HI.Prognostic and predictive value of a breast cancer expression signature in localized prostate cancer. JAMA Oncol 2017 May 11; [e-pub]. 

JWatch