Science Links Japan | Histopathological Study of Sessile Polypoid Cancer of the Colon and Rectum: Analysis of Origin and Development Based on Histomorphometric Analysis and K-ras Codon 12 Mutation Status.

Histopathological Study of Sessile Polypoid Cancer of the Colon and Rectum: Analysis of Origin and Development Based on Histomorphometric Analysis and K-ras Codon 12 Mutation Status.

Accession number;02A0146455

Title;Histopathological Study of Sessile Polypoid Cancer of the Colon and Rectum: Analysis of Origin and Development Based on Histomorphometric Analysis and K-ras Codon 12 Mutation Status.

Author; ODA YOSHIO (Tohodai I Naikagakudaiichi) HAMATANI SHIGEHARU (Tohodai I Omoribyoin Byorigakukenkyushitsu)

Journal Title;Journal of the Medical Society of Toho University

Journal Code:G0654A

ISSN:0040-8670

VOL.48;NO.6;PAGE.412-423(2001)

Figure&Table&Reference;FIG.3, TBL.11, REF.34

Pub. Country;Japan

Language;Japanese

Abstract;We analyzed the origin and development of sessile polypoid cancers (SPCs) of the colon and rectum to gain a better understanding of the relation between intramucosal polypoid colorectal cancers and colorectal cancers with invasion extending to the submucosa or deeper. SPC was defined as an intramucosal cancer without a distinct peduncle that has mucosa overlying the tumor protruding to a point at least two times higher than the normal mucosa and a horizontal spread of 10 mm or more. SPC limited to the mucosa was designated SPC-m. Intramural invasive cancer originating from SPC in which the intramucosal tumor front retained SPC components and invaded either the submucosa or the muscularis propria was designated as SPC-sm or SPC-mp, respectively. Thirty SPC-m, 21 SPC-sm, and 11 SPC-mp cancers were studied with respect to clinicopathological characteristics, histological diagnosis based on histomorphometric analysis, and K-ras codon 12 mutations (PCR-PHFA method). Clinicopathologically, the intramural invasion front of some SPCs had a depressed structure (10% of SPC-sm, about 30% of SPC-mp). Histopathologically, adenoma was present in about 40% of SPC-m, but this figure gradually decreased with advancing intramural spread. The cancer component of SPC-m was characterized by carcinoma with low-grade cytological atypia, whereas SPC-sm and SPC-mp were characterized by carcinoma with high-grade cytological atypia. K-ras codon 12 mutations were found in about 60% of SPC-m, 50% of SPC-sm, and 70% of SPC-mp. The presence of positive mutations in the mucosa correlated with a villous duct-like structure in at least part of the intramucosal lesions. In conclusion, high-grade intramural invasion by SPC may be associated with erosion and ulcer formation, suggesting an association with ulcer localized type (type 2) advanced cancer. The oncogenesis of SPC apparently involves malignant transformation of adenoma.... (author abst.)

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