The PIK3CA gene encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K), a lipid kinase central to the PI3K/AKT/mTOR signaling pathway. This pathway regulates critical cellular processes, including proliferation, survival, and metabolism. PIK3CA mutations, particularly in exons 9 and 20 (e.g., E542K, E545K, H1047R), are among the most frequent oncogenic alterations in cancers such as breast, colorectal, and ovarian carcinomas. These mutations lead to constitutive PI3K activation, driving uncontrolled cell growth and tumor progression. Antibodies targeting PIK3CA are essential tools for detecting protein expression, mutation status, and activation levels in research and diagnostics. They are widely used in techniques like Western blotting, immunohistochemistry (IHC), and immunofluorescence to study PI3K pathway dysregulation in cancer models or clinical samples. Specific monoclonal antibodies, such as those recognizing mutant epitopes (e.g., H1047R), enable precise identification of oncogenic variants, aiding in patient stratification for targeted therapies like PI3K inhibitors (e.g., alpelisib). Validation of PIK3CA antibodies often involves knockout cell lines or mutation-specific controls to ensure specificity. In clinical settings, detecting PIK3CA mutations via antibody-based assays or sequencing helps guide treatment decisions, particularly in hormone receptor-positive breast cancer and other malignancies where PI3K targeting is therapeutic. However, challenges remain in standardizing detection methods and interpreting heterogeneous mutation patterns.