CpG Island Methylation in Sessile Serrated Adenomas Increases With Age, Indicating Lower Risk of Malignancy in Young Patients

Among sessile serrated adenomas (SSAs) with identical histologic features, some never progress, whereas others become dysplastic and develop into invasive cancers. Development of the CpG island methylator phenotype is a feature of SSA progression; we examined the CIMP status of 448 SSAs and examined the association with patient clinical data. Overall, 190 SSAs were CpG island methylator phenotype-positive. CpG island methylator phenotype positivity was associated with older patient age (P < .001) and proximal polyp site (P < .001), but not with patient sex (P = .94) or polyp size (P = .34). These results might be used to improve SSA surveillance guidelines.