Analysis of K-ras mutations and expression of cyclooxygenase-2 and gastrin protein in laterally spreading tumors

Kenichiroh Mukawa, Shigehiko Fujii, Jun Takeda, Kazuaki Kitajima, Keiichi Tominaga, Yoko Chibana, Mikio Fujita, Kazuhito Ichikawa, Shigeki Tomita, Yuko Ono, Johji Imura, Hitoshi Kawamata, Tsutomu Chiba, Hideyuki Hiraishi, Akira Terano, Takahiro Fujimori

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    Abstract

    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.

    Original languageEnglish (US)
    Pages (from-to)1584-1590
    Number of pages7
    JournalJournal of Gastroenterology and Hepatology (Australia)
    Volume20
    Issue number10
    DOIs
    StatePublished - Jan 1 2005

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    Keywords

    • Colorectal tumor
    • Cyclooxygenase-2
    • Gastrin
    • K-ras
    • Laterally spreading tumor

    ASJC Scopus subject areas

    • Gastroenterology
    • Hepatology

    Cite this

    Mukawa, K., Fujii, S., Takeda, J., Kitajima, K., Tominaga, K., Chibana, Y., Fujita, M., Ichikawa, K., Tomita, S., Ono, Y., Imura, J., Kawamata, H., Chiba, T., Hiraishi, H., Terano, A., & Fujimori, T. (2005). Analysis of K-ras mutations and expression of cyclooxygenase-2 and gastrin protein in laterally spreading tumors. Journal of Gastroenterology and Hepatology (Australia), 20(10), 1584-1590. https://doi.org/10.1111/j.1440-1746.2005.03897.x