Abstract 3367: Clinicopathological significances of CD44v6 in colon cancer
Authors: Saitou Seiya , Watanabe Masayuki , Okabe Hirohisa , Kinoshita Kouiti , Kurashige Junji , Iwatuki Masaaki , Baba Yoshihumi , Hayashi Naoko , Baba Hideo 
Published: June 2012

Abstract
Background: CD44 is a cell adhesion molecule, which belongs to the family of hyaluronan binding proteins. CD44 pre-mRNA is encoded by 20 exsons, 10 of which can be regulated by alternative splicing. Recently, CD44 has been noticed as one of cancer stem cell marker in many solid tumors. And CD44 has been reported to be relevant to epithelial mesenchymal transition (EMT). We studied clinicopathological significances and association with EMT of CD44 and CD44v6 in colon cancer. Subject and Methods: Formalin fixed, paraffin-embedded blocks were obtained from 113 patients with stage II/III colorectal cancer who received surgical treatment in our hospital from 2000 to 2007. And we studied immunohistochemistrical analysis. Mouse anti-human monoclonal antibody against CD44std and CD44v6 (Bender Medsystems) was used. We counted positive cells within the invasive front of tumor. Survival rates were calculated using the Kaplan-Meier method, and significant differences in survival were determined by the log-rank test. Result: We researched the importance of CD44, CD44v6 expression in colorectal cancer by immunohistochemistry. We used clinicopathological factors including age, sex, location of primary, tumor size, histological type, invasion depth, vascular invasive, TMN stage and prognosis. There were little differences in clinicopathological factors between high expression and low expression group of CD44 and CD44v6. CD44v6 expression showed significantly inverse correlation with E-cadherin expression (P=0.025) and positive correlation with Vimentin (P=0.007). CD44v6 positive cells that were consistent with Vimentin positive cells were located along the invasive front. All of poorly differentiated cases showed significantly CD44v6 high expression (P&lt;0.0001). CD44v6 high expression group was associated with significant shorter disease free survival (P=0.021) and overall survival (P=0.041) than that of low expression group. We compared expression in CD44, CD44v6, E-cadherin and Vimentin between primary and liver metastasis. However, all of them showed similar expression between primary and liver metastasis. In multivariate analysis, CD44v6 was the only independent factor related to recurrence(P = 0.036, HR: 2.26, 1.06- 4.83) and overall survival (P = 0.046, HR: 2.46, 1.02- 5.95). On the other hand, CD44 expression showed no correlation with E-cadherin and Vimentin and significantly inverse correlation with CD44v6(P=0.01). CD44 high expression group showed significant longer disease free survival(P=0.034) than that of low expression group. Conclusion: CD44v6 is related to EMT and is an independent prognostic factor in colorectal cancer.
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 3367. doi:10.1158/1538-7445.AM2011-3367