BRCA2 Mutations Account for >50% of Mutations in Pancreatic Adenocarcinoma

Mutations in BRCA2 account for more than 50% of patients with pancreatic adenocarcinoma with an identified susceptibility syndrome, a new study published online ahead of print in the journal Cancer has shown.¹

Because indications for genetic testing and counseling are not well-defined for pancreatic adenocarcinoma, researchers at Memorial Sloan Kettering Cancer Center in New York, NY, sought to determine the prevalence of mutations and characteristics that are predictive of an inherited predisposition.

For the study, researchers analyzed data from 175 patients with pancreatic adenocarcinoma who underwent clinical genetics assessment at their institution between 2011 and 2014.

Results showed that among the 159 patients who pursued genetic testing, 15.1% (95% CI: 9.5-20.7) had pathogenic mutations, including BRCA2 (13 mutations), BRCA1 (4 mutations), p16 (2 mutations), PALB2 (1 mutation), and Lynch syndrome (4 mutations).

Researchers found that BRCA1/BRCA2 prevalence was 13.7% in patients of Ashkenazi Jewish ancestry (95 patients) and 7.1% in non-Ashkenazi Jewish patients. The mutation prevalence was 16.7%, 15.8%, and 7.4% in Ashkenazi Jewish patients with a strong, weak, or absent family history of BRCA-associated cancers.

“[Ashkenazi Jewish] patients were found to have high BRCA1/BRCA2 prevalence regardless of personal/family history, suggesting that ancestry alone indicates a need for genetic evaluation,” the authors wrote.

The study also demonstrated that the mean age at the time of diagnosis in all mutation carriers was 58.5 years compared with 64 years among those not carrying a mutation (P=0.02); however, no patients with early-onset pancreatic cancer harbored a BRCA2 mutation.

“With the exception of BRCA2-associated [pancreatic adenocarcinoma], an inherited predisposition for PAC is associated with an earlier age at PAC diagnosis, suggesting that this subset of patients may also represent a population warranting further evaluation,” the authors concluded.

Reference

1. Salo-Mullen EE, O’Reilly EM, Kelsen DP, et al. Identification of germline genetic mutations in patients with pancreatic cancer [published online ahead of print October 6, 2015]. Cancer. doi: 10.1002/cncr.29664.