We investigated the associations between the HER2 Ile655Val polymorphism and clinical outcomes in women with HER2-negative breast cancer and with HER2-positive breast cancer who received trastuzumab or who did not.
In a retrospective cohort study of 237 women with non-metastatic HER2-positive breast cancer treated with trastuzumab, traditional risk factors were assessed by review of medical records, alcohol use by an administered questionnaire to women (n=132), and HER2 polymorphisms (Ile655Val and Ala1170Pro) using TaqMan assays (n=73).
A nonsense mutation in PTPN11 (K99X), a pathogenic CCND1 splice site variant (P241P), a hotspot missense mutation in PIK3CA (E542K) and a hotspot missense mutation in TP53 (R249S); were observed in 25%, 75%, 30% and 40% of the HER2+ BC tissue samples, respectively.