GAB2 and ovarian carcinoma: The PI3K pathway is frequently activated in HGSOCs11 (often being described as PI3Kness) and associated with resistance to chemotherapy.12 As mutation of PIK3CA is rare (<1%), the observed PI3K pathway activation might be driven by other alterations such as loss of phosphatase and tensin homolog.13 We and others have shown that ovarian cancer cell lines overexpressing GAB2 are dependent on GAB2 for PI3K pathway activation and are sensitive to PI3K inhibition but not MEK inhibition,4, 14 suggesting GAB2 overexpression as a mechanism contributing to the PI3Kness in HGSOCs.