Evaluation of PIK3CA mutations as a biomarker in Chinese breast carcinomas from Western China

Article type: Research Article

Authors: Cheng, Jingliang^{a; 1} | Fu, Shangyi^{b; 1} | Wei, Chunli^{a; c; 1} | Tania, Mousumi^a | Khan, Md. Asaduzzaman^{a; d} | Imani, Saber^a | Zhou, Baixu^a | Chen, Hanchun^e | Xiao, Xiuli^f | Wu, Jingbo^g | Fu, Junjiang^{a; c; h; *}

Affiliations: [a] Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000, China | [b] Honors College, University of Houston, Houston, TX 77204, USA | [c] State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau (SAR) 999078, China | [d] Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh, Vietnam | [e] Department of Biochemistry, School of Life Sciencesand the State Key Laboratory of Medical Genetics, Central South University, Changsha, Hunan 410013, China | [f] Department of Pathology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China | [g] Department of Oncology, Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, China | [h] Judicial Authentication Center, Southwest Medical University, Luzhou, Sichuan 646000, China

Correspondence: [*] Corresponding author: Junjiang Fu, Key Laboratory of Epigenetics and Oncology, The Research Center for Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan 646000, China. E-mail:[email protected]

Note: [1] They are co-first authors.

Abstract: 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, phosphatidylinositol 3-kinase, PIK3CA gene, DNA mutation, pyrosequencing, Western China

DOI: 10.3233/CBM-160380

Journal: Cancer Biomarkers, vol. 19, no. 1, pp. 85-92, 2017