The data from previous clinical trials on the treatment of other tumor types showed that clinical response may depend on the presence of the mutations in EGFR (11) and in genes encoding downstream proteins involved in the signal transduction, including Kirsten rat sarcoma viral oncogene homolog (KRAS), v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) or phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit α (PIK3CA) (12). The gene discussed is PIK3CA; the disease is neoplasm.