Biology of the estrogen receptor, GPR30, in triple negative breast cancer

BackgroundTriple-negative (TN) breast cancer lacks a known signaling pathway amenable to targeted therapy. The authors hypothesized that the G protein–coupled receptor GPR30 may be present in TN breast cancer and serve a role for tumor growth.MethodsA retrospective pathology study and chart review were conducted. All patients aged ≤49 years from 2000 to 2008 were included (n = 24). Concurrent patients aged ≥50 years were randomly selected. Paraffin sections were stained for GPR30 and reviewed by a pathologist blinded to estrogen receptor and progesterone receptor status. Disease-free survival was analyzed versus age and receptor status. Means were compared using 2-sample t tests and proportions using chi-square analysis.ResultsTwenty-seven patients tested GPR30 positive and 21 GPR30 negative. Seventeen of 18 TN cancers tested positive for GPR30 (P < .0001). Recurrence at a mean follow-up of 36 months was 22.2% in the GPR30-positive group and 9.5% in the GPR30-negative group.ConclusionsGPR30 is prevalent in TN breast cancer and associated with young age and possibly recurrence.