Clinical-Pathologic Analysis of Breast Cancer With PIK3CA Mutations in Chinese Women.

Purpose: Mutations of PIK3CA have recently been shown to play an important role in the pathogenesis and progression of breast neoplasms. The prevalence of PIK3CA in Chinese breast cancer patients may be underestimated. Therefore, we investigated the distribution of somatic PIK3CA mutation in Chinese breast cancer patients and explored their role in tumor phenotypes.

Methods: Mutational analysis of PIK3CA was done in 113 primary breast cancers of Chinese women used Amplification refractory mutation system (ARMS). The relationship of PIK3CA mutations with several clinicopathologic characteristics was analyzed.

Results: PIK3CA gene mutation was identified in 43(38.05%) cases and has a more significant difference between exon 9 and 20. HER2 gene amplification was 32.6% in 43 cases of PIK3CA mutation, but 37.1% in 70 cases of non-mutation (χ = 0.245, P > 0.05). There was no significant correlation of the age distribution, lymph node status, histological tumor grading, ER and/or PR and P53 between 2 groups (P > 0.05).

Conclusion: A high frequency of somatic PIK3CA mutation was detected in Chinese breast cancer patients, especially in exon 20. The relationship between PIK3CA gene mutation and clinical pathological features of breast cancer needs to be further studied in a large series of patients. PIK3CA mutations seem to have the potential to be used in target treatment and as an indicator of prognosis.