Further analysis of the TCGA gastric cancer patient data revealed that PI3K/AKT/mTORC1 signaling pathway alterations occur in 33% of gastric cancer (142 of 441 samples) with PIK3CA, AKT, and PTEN alterations being the most common genetic alterations (Figure 6—figure supplement 1A). The gene discussed is PIK3CA; the disease is gastric cancer.