BRAF and cancer: Therefore, sessile serrated adenomas with serrated or adenomatous dysplasia may be the precursor lesions of BRAF-mutant mismatch repair-proficient cancers, the most aggressive molecular subgroup of colorectal carcinomas.22, 23 Compared with dysplasia not otherwise specified, the adenomatous dysplasia is more pronounced at the top of the lesion and is uniform in appearance, resembling dysplasia in conventional adenomas.