It is recommended in the following situations: (1) equivocal cytological atypia possibly secondary to inflammation, prolapse or cross-cut of the crypt bases; (2) piecemeal resection with separate fragments of dysplasia and sessile serrated adenoma, where loss of MLH1 expression in the dysplastic fragments favors sessile serrated adenoma with dysplasia rather than conventional adenoma admixed with sessile serrated adenoma; and (3) lesions with mild morphological changes of minimal deviation dysplasia to support the diagnosis of dysplasia. This evidence concerns the gene MLH1 and adenoma.