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K‐ras Codon 12 Mutation and Horizontal Growth of Colorectal Cancer
Author(s) -
SAITO Kenichi,
OGAWA Akira,
OHKI Ichiro,
MORI Masatomo
Publication year - 1999
Publication title -
digestive endoscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.5
H-Index - 56
eISSN - 1443-1661
pISSN - 0915-5635
DOI - 10.1111/j.1443-1661.1999.tb00209.x
Subject(s) - colorectal cancer , carcinogenesis , mutation , cancer , medicine , biology , gastroenterology , pathology , genetics , gene
K‐ras codon 12 mutations and horizontal growth were examined in 121 colorectal cancers to clarify genetic contributions to tumorigenesis. Invasion was submucosal [SMCa] in 61 cases and to the muscularis propria [PMCa] in 60. Growth patterns were further classified into polypoid [PG] and nonpolypoid [NPG] types. Horizontal growth cancers were defined as lesions associated with horizontally aligned cancerous glands. The K‐ras codon 12 mutation frequency was higher in PG SMCa than in NPG SMCa (49% versus 0%, respectively), and in PG PMCa compared to NPG PMCa (60% versus 24%, respectively). The K‐ras codon 12 mutation was less frequent in horizontal growth SMCa than in nonhorizontal growth SMCa (0% versus 49%, respectively), and in horizontal growth PMCa compared to nonhorizontal growth PMCa (0% versus 64%, respectively). The frequency of horizontal growth was higher in NPG SMCa than in PG SMCa (100% versus 0%, respectively), and in NPG PMCa compared to PG PMCa (76% versus O%, respectively). The frequencies of NPG carcinoma with horizontal growth and with wild type K‐ras in SMCa were both 26%. NPG carcinoma with horizontal growth and with wild type K‐ras in PMCa both occurred at a frequency of 22%. Our results suggest that NPG type carcinomas with horizontal growth do not result from K‐ras codon 12 mutations, and may arise through very different genetic pathways and histologic processes. At least 22% of early colorectal cancers may progress to advanced cancer of superficial origin. (Dig Endosc 1999; 11: 125–131)