Pathogenic or likely pathogenic germline variants were fairly prevalent among men with prostate cancer, however, ethnicity was not associated with risk of carrying these variants, according to a retrospective study.1
Researchers looked at results from 1351 men with prostate cancer of any stage who underwent germline testing for the disease, which is among the most heritable cancers. Of the included men, the majority were white (78%). Other participants were Ashkenazi Jewish (11%), African American/Canadian (3%), Hispanic (2%), Asian/Pacific Islander (2%), or classified as other (4%).
“Although the slightly lower representation of these ethnicities in this cohort (7%) than what has been previously reported (9%−11%) may partially be due to selection biases, all numbers from these studies are significantly lower than the 25% of new cancer cases of prostate cancer in the United States represented by these populations,” the researchers wrote.
In all, 13.8% of participants carried a pathogenic or likely pathogenic variant. This is slightly higher than reported in previous literature, and may be “due to the inclusion of variants for genes such as APC and MUTYH, which have not been shown to increase prostate cancer risk in particular.”
The most common variants were BRCA2 (3.4%), CHEK2 (2.8%), MUTYH (1.8%), and ATM (1.7%). Men of Ashkenazi Jewish descent were significantly more likely to carry BRCA2 variants than white men (6.7% vs. 2.8%; P <.05). Outside of this, there was no significant difference in the frequency of individual pathogenic or likely pathogenic variants between ethnicities.
In addition, 1 in 5 men carried a variant of unknown significance; more than one-third of African-American men (36.6%) and Asian/Pacific Islanders (33.3%) had variants of unknown significance (P <.01).
“Further studies in these groups will facilitate reclassification of [variants of unknown significance], which will in turn better define opportunities for early cancer detection, cancer risk modification, and targeted therapeutics,” the researchers concluded.
Kwon DH, Borno HT, Cheng HH, et al. Ethnic disparities among men with prostate cancer undergoing germline testing [published online October 17, 2019]. Urol Oncol. doi: 10.1016/j.urolonc.2019.09.010