Whilst mutations to the PIG-A gene have not been identified as a causative risk factor for OAC, and patients with the underlying PNH condition are not at more risk of these cancers compared to their normal counterparts, it is plausible that the detection of higher circulating GPI-anchor deficient erythrocytes in patients with cancer could be a measure of an underlying susceptibility to mutation. The gene discussed is PIGA; the disease is cancer.