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: Ichikawa Yasushi , Ishikawa Takashi , Shimizu Daisuke , Goto Ayumu , Shimamura Takeshi , Suwa Hirokazu , Tatsumi Kenshi , Watanabe Kazuteru , Ota Mitsuyoshi , Fujii Shoichi , Kawamata Mayumi , Akimoto Kazunori , Nagashima Yoji , Takahashi Hirokazu , Nakajima Atsushi , Ohno Shigeo , Endo Itaru 
Published: June 2012

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 & 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