Abstract 1519: In laterally spreading type tumors (LSTs) of the colon or the rectum, expression of the atypical protein kinase C lambda/iota is correlated to expression of beta-catenin and Type IV collagen
Authors: Yasushi Ichikawa, Takashi Ishikawa, Daisuke Shimizu, Ayumu Goto, Takeshi Shimamura, Hirokazu Suwa, Kenshi Tatsumi, Kazuteru Watanabe, Mitsuyoshi Ota, Shoichi Fujii, Mayumi Kawamata, Kazunori Akimoto, Yoji Nagashima, Hirokazu Takahashi, Atsushi Nakajima, Shigeo Ohno, Itaru Endo
Journal: Cancer Research (2011)

Abstract Background: Epithelial cell polarity is guided by highly conserved polarity proteins. Especially aPKC lambda/iota is a pivotal regulator of cell polarity, and related to oncogenecity. LST is a flat-type colorectal tumor that is macroscopic morphologic concept in contrast to a protruded-type tumor. Cancer in LST also show a superficial-replacing growth and less invasive in an early stage of cancer. Previously, we showed expression of aPKC l/i is important for determination of structures in LSTs. In the present study, we examined morphologic characteristics of adenomatous and cancerous lesions of LSTs, compared with those of protruded-type tumors or flat-depressed type tumors from expression of 4 factors. Material &amp; Methods: In these studies, 37 flat type colorectal tumors and 20 polypoid-type colorectal tumors resected endoscopically or surgically in the Yokohama City University Hospital from 1998 to 2007 were examined. Flat type tumors included 15 LST adenomas, 9 LSTs with cancer in situ, and 13 flat-depressed type tumors. Polypoid-type tumor included 11 adenomas and 9 cancer in situ. To detect microscopic morphological characteristics of LSTs, hematoxylin and eosin-staining was carried out on 4 um of each section. Localization of beta-catenin or E-cadherin, conservation of basement membrane and aPKC l/i were investigated by immunohistochemistry. Results: LST tumors looked like as if they had 2 layers composed of tumorous layer in the apical side and normal layer in the bottom side. Same structure can be detected in cancer in situ of LST showing 2 layers of normal in the bottom and cancer in the apical. In aPKC l/i expression, almst all of LST adenomas were 1+, and about 60% of cancer in situ in LST also showed +1. On the other hands about half of polypoid-type adenomas were 2+, and 70% of cancer in polypoid-type adenoma were 3+. Pearson's correlation coefficient using expression results of the all samples showed a highly significant statistical positive correlation was observed between expression of aPKC lambda/iota and both the beta catenin (r = 0.842) and the type IV collagen (r = 0.823). Conclusion: Both adenoma and cancer in situ of LSTs showed a unique growth morphology as neoplastic cells tend to spread along the surface of the lumen and 2 layer structure, which is different from expanding growth pattern showed by polypoid tumor or invasive cancer. Those morphological characteristics were built up by adequate coexpression of beta-catenin, type IV collagen and aPKC lambda/iota. (Supported by the grants of Japanese Ministry of Education, Culture, Sports and Science) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1519. doi:10.1158/1538-7445.AM2011-1519