title: Correlation of polypoid colorectal adenocarcinoma with pre-existing adenomatous polyps and KRAS mutation.
abstract: Cetuximab is an anti-epidermal growth factor receptor that helps effectively treat patients with advanced colorectal adenocarcinoma without KRAS activating mutations. KRAS mutations are associated with 16% to 50% of isolated villous adenomas and approximately 30% of colorectal cancer. Correlation between the gross and histological subset of colorectal adenocarcinoma with KRAS mutation is unknown. Archived surgical resection specimens of colorectal adenocarcinoma (n = 42) and villous adenoma (n = 9) were collected. The gross appearance and histopathological features of these lesions were thoroughly reviewed, including the presence of a pre-existing adenomatous polyp. DNA was extracted from formalin-fixed, paraffin-embedded tissue sections and then subjected to TaqMan real-time polymerase chain reaction to detect the seven most common KRAS mutations. KRAS mutations were found in 13 of 42 cases (31%) of colorectal adenocarcinoma and 7 of 9 cases (78%) of villous adenoma. All 13 cases of colorectal carcinoma with a KRAS mutation showed a gross polypoid configuration, compared to no KRAS mutation in the colorectal carcinomas with ulcerative configuration. In addition, 13 of 17 of these cases (76%) had histological features of adenocarcinoma with a persistent preexisting adenomatous polyp with villous architecture. In summary, grossly polypoid colorectal adenocarcinomas with a persistent pre-existing adenomatous polyp with villous architecture are strongly associated with KRAS mutations.
authors.affiliation: Department of Pathology, Dartmouth-Hitchcock Medical Center and Norris Cotton Cancer Center, Lebanon, NH, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Chen
authors.forename: Joel A
authors.initials: JA
authors.lastname: Lefferts
authors.forename: Mary C
authors.initials: MC
authors.lastname: Schwab
authors.forename: Arief A
authors.initials: AA
authors.lastname: Suriawinata
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Tsongalis
mesh_terms: D000230:Adenocarcinoma / Q000150:complications / Q000235:genetics* / Q000473:pathology; D018256:Adenomatous Polyps / Q000150:complications* / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000150:complications / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics*
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins