MLH1 and ovarian carcinoma: Another example of a gene whose methylation-associated silencing is associated with relative drug resistance is the DNA mismatch repair gene hMLH1. Loss of hMLH1 is associated with increased resistance to platinum compounds in vitro (Strathdee et al, 1999) and acquired methylation (detectable in peripheral blood) during treatment predicts poorer outcome following chemotherapy for ovarian cancer (Gifford et al, 2004).