MAP2K7 and adenoma: By making use of a recently conceived combination of oligonucleotide primers it could be shown that: (1) In 65% of the analyzed serrated lesions and in 61% of the traditional adenomas of the colon and rectum, at least one of the four genes studied was altered; (2) in 92.3% of the serrated lesions with mutations and in 76% of the adenoma samples with mutations either the Ras-Raf-MEK-MAPK or the Wnt signaling cascade was altered; (3) in 35% of the serrated lesions and in 39% of the adenomas neither the Wnt pathway nor the Ras-Raf-MEK-MAPK pathway were affected.