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Analysis of K‐ras mutations and expression of cyclooxygenase‐2 and gastrin protein in laterally spreading tumors
Author(s) -
MUKAWA KENICHIROH,
FUJII SHIGEHIKO,
TAKEDA JUN,
KITAJIMA KAZUAKI,
TOMINAGA KEIICHI,
CHIBANA YOKO,
FUJITA MIKIO,
ICHIKAWA KAZUHITO,
TOMITA SHIGEKI,
ONO YUKO,
IMURA JOHJI,
KAWAMATA HITOSHI,
CHIBA TSUTOMU,
HIRAISHI HIDEYUKI,
TERANO AKIRA,
FUJIMORI TAKAHIRO
Publication year - 2005
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1111/j.1440-1746.2005.03897.x
Subject(s) - gastrin , immunohistochemistry , medicine , cyclooxygenase , mutation , colorectal cancer , incidence (geometry) , pathology , polymerase chain reaction , cancer research , gastroenterology , cancer , biology , gene , enzyme , genetics , biochemistry , physics , secretion , optics
Background and Aim: Recent advances in colonoscopic techniques have led to the increased detection of, and interest in, superficial type colorectal tumors, and a new category, the ‘laterally spreading tumor (LST)’, has been proposed. However, the characteristics of the genetic alterations in these LSTs have not yet been fully determined. We therefore classified LSTs as LST‐granular (LST‐G) or LST‐non‐granular (LST‐NG), according to their macroscopic appearance, and examined the genetic alterations in these two tumor groups compared with those in protruded type tumors. Methods: We obtained a total of 62 colorectal tumors, including 26 protruded type, 17 LST‐G and 19 LST‐NG, from specimens resected surgically or endoscopically. We examined K‐ras codon 12 mutations by using the polymerase chain reaction‐restriction fragment length polymorphism method and by fluorescence direct sequencing. We also performed immunohistochemistry to analyze cyclooxygenase (COX)‐2 and gastrin abnormalities. Results: The incidence of K‐ras mutation was 50.0% in protruded type tumors, 76.5% in LST‐G, and 26.3% in LST‐NG. The frequencies of COX‐2 overexpression were 73.1, 88.2, and 31.6%, respectively, and those of gastrin overexpression were 61.5, 82.4, and 26.3%, respectively. Therefore, LST‐G is similar to protruded type tumors in that the incidence of K‐ras mutation and the frequencies of COX‐2 and gastrin overexpression are high. LST‐NG differs from both of these tumor types in that the values of these three indicators are all low. Conclusions: These results show that LST‐G and LST‐NG have different genetic alterations. © 2005 Blackwell Publishing Asia Pty Ltd