PIK3CA is a gene that provides instructions for making a protein called p110α, which is part of a larger group of proteins known as phosphoinositide 3-kinases (PI3Ks). This protein plays a crucial role in various cellular functions, including cell growth, proliferation, and survival. Mutations in the PIK3CA gene can lead to abnormal activation of the PI3K pathway, contributing to the development of several types of cancer, including breast and colorectal cancers. Understanding PIK3CA is important for developing targeted therapies that can inhibit its activity in cancer treatment.