Abstract 5176: Implications of clonality relationship and CD133 expression between cancer synchronous/preceding adenomas and their colorectal adenocarcinoma pairs

Abstract

Abstract Background: It is thought that each cell only generates a unifocal lineage that is independent from one another in colorectal adenoma-carcinoma progression. This study compared the genome-wide copy number aberration profiles of adenoma and primary colorectal carcinomas (CRCs) derived from the same patient to trace their clonality relationship. The CD133 positive cells, putative colorectal cancer stem cells, are capable of tumor initiation and metastasis. Therefore, we also investigated the use of CD133 expression as a potential marker for prediction of subsequent risk of colorectal cancer. Methods: Microarray-based comparative genomic hybridization (aCGH) experiments were performed on 18 cancer-synchronous polyps (CSP) and 9 cancer-preceding polyps (CPP), together with their corresponding cancers, and 16 cases of incidental polyps (IP). Genome-wide copy number imbalances revealed by aCGH were analyzed to determine the clonal relationship between the paired adenomas and carcinomas. CD133 expression in cancerous tissue was evaluated by immunohistochemistry (IHC) staining. Results: There were more CGH lesions in CRC than CSP/CPP, and least in IP. Clonal relationship determined by tissues' aCGH profiles showed that 50 percent of CSP and 67 percent of CPP were clonally related to the concurrent or subsequent cancers, respectively. The expression level of stem cell marker CD133 was significantly higher in CSP/CPP than in IP (P<0.0001), and even higher CD133 staining were observed in CSP/CPP that were clonally related to the corresponding carcinomas than CSP/CPP that were unrelated (P<0.05). Conclusions: In the present study more than half of the polyp-carcinoma pairs share highly similar pattern of numerical chromosomal aberrations implying that the pairs might descent from the same monoclonal cell origin. The high expression of stem cell marker CD133 in colorectal adenomas is predictive of high cancer risk for polyp-bearing patients. Citation Format: Chih-Yung Yang, Ju-Yu Tseng, Chi-Hung Lin. Implications of clonality relationship and CD133 expression between cancer synchronous/preceding adenomas and their colorectal adenocarcinoma pairs. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5176. doi:10.1158/1538-7445.AM2014-5176