HER2 somatic mutations are associated with poor survival in HER2-negative breast cancers

Summary

It is well documented that HER2 overexpression/amplification is associated with the poor survival in breast cancer patients. However, it is largely unknown whether HER2 somatic mutations are associated with the survival in HER2-negative breast cancer patients. Here, we identified HER2 somatic mutations in tumors from 1,348 unselected breast cancer patients by sequencing the entire HER2 coding region. All these mutations were tested for in corresponding blood samples to determine whether they were somatic or germline mutations. We further investigated the associations between the HER2 somatic mutations and recurrence-free survival (RFS) and distant recurrence-free survival (DRFS) in this cohort of patients. We found that 27 of 1,348 (2.0%) of these patients carried a HER2 somatic mutation. In vitro experiments demonstrated that some of novel mutations and those with unknown functions increased HER2 activity. HER2 status was available for 1,306 patients, and the HER2 somatic mutation rates in HER2-positive (n=353) and HER2-negative breast cancers (n=953) were 1.4% and 2.3%, respectively. Among the HER2-negative patients, those with a HER2 somatic mutation had a significantly worse recurrence-free survival (unadjusted hazard ratio [HR] =2.67; 95% confidence interval [CI]: 1.25-5.72, P=0.002) and distant recurrence-free survival (unadjusted HR=2.50; 95% CI: 1.10-5.68, P=0.004) than those with wild-type HER2. Taken together, our findings suggested that HER2 somatic mutations occur at a higher frequency in HER2-negative breast cancer, and HER2-negative breast cancer patients with these mutations have poor survival. Therefore, HER2-negative patients with a HER2 somatic mutation are potentially good candidates for HER2-targeted therapy.

This article is protected by copyright. All rights reserved.

from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2jS9ekN
via IFTTT