Background: PIK3CA gene encodes the p110 α catalytic subunit of the oncoprotein phosphatidylinositol 3-kinase (PI3 K) which regulates many biological processes such as cell proliferation, differentiation, migration and survival through the activation of various signaling pathways.
Objective: In this study, we have investigated the possible somatic mutations in PIK3CA gene in invasive ductal breast carcinomas of Chinese women from Western China.
Methods: Genomic DNA was extracted from the formalin-fixed paraffin-embedded (FFPE) tissue samples. The hotspot mutations in PIK3CA gene of exon 9 and exon 20 were studied by pyrosequencing.
Results: The sequencing identified two hotspot mutations in exon 20 of one cancer samples at p. H1047L (c. 3140A > T) and eight cancer sample at p. H1047R (c. 3140A > G). No mutation in exon 9 of PIK3CA gene was found in these breast cancer tissue samples. PIK3CA mutations showed surprising clinicopathological features in breast cancer patients, as incidence of lymph node invasiveness is increased in the patients with PIK3CA mutation. In addition, all the patients showed tumor size bigger than 3 cm in diameter. It is important that for early detection and early treatment for BC in developing countries or areas like Western China, and for people to provide popularization education using scientific knowledge in cancer fields.
Conclusions: This study identified PIK3CA mutations in breast carcinoma patients of Western China that will enable a more rapid molecular diagnosis, and provide a stronger rationale evidence for development of precision therapeutic approaches as well as promising therapeutic targets for breast cancer treatment or patient management.
Keywords: Breast cancer; DNA mutation; PIK3CA gene; Western China; phosphatidylinositol 3-kinase; pyrosequencing.