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Understanding MBC > What Is a PIK3CA Mutation?

What is a PIK3CA Mutation?

The PIK3CA mutation is a type of biomarker. PIK3CA mutations are somatic mutations, which are not passed down from parent to child (not inherited). These are changes to the genes that give cells instructions about what to do and how often to grow and divide.1,2

DNA is found in all cells and is made up of a variety of different “genes.” Each gene is a set of instructions for making a different part of the cell. The PIK3CA gene gives instructions for part of the cell known as “PI3Kα” (PI3K-alpha).9,17


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  1. Approved content from Novartis PDF G-ALP-1217818 Alpelisib BYL Unbranded Patient Brochure
  2. US National Library of Medicine. PIK3CA gene. Genetics Home Reference. Accessed September 25, 2019.
  3. Sobhani N, Roviello G, Corona SP, et al. The prognostic value of PI3K mutational status in breast cancer: A meta-analysis. J Cell Biochem. 2018;119(6):4287-4292.
  4. Sabine VS, Crozier C, Brookes CL, et al. Mutational analysis of PI3K/AKT signaling pathway in tamoxifen exemestane adjuvant multinational pathology study. J Clin Oncol. 2014;32(27):2951- 2958.
  5. Andre F, Ciruelos E, Rubovszky G, et al. Alpelisib for PIK3CA-mutated, hormone receptor-positive advanced breast cancer. N Engl J Med. 2019;380(20):1929-1940.
  6. American Society of Clinical Oncology. Biomarkers to guide treatment for early-stage breast cancer. recommendations-patients/biomarkers-guide-treatment-early-stage-breast-cancer. Accessed September 25, 2019.