Abstract 5210: Over-expression of cancer stem cell markers predicted poor prognosis in colorectal cancer

Abstract

Abstract Introduction: Previous reports have demonstrated that CD133+CD44+ cells might be putative colorectal cancer stem cells (CSCs). Intestinal stem cell marker is already identified as LGR5 in mice, and it is also reportedly in human. However the correlation of CSCs and normal stem cell are unclear. The stem-cell-specific loss of APC (adenomatous polyposis coli) results in progressively growing neoplasia. Therefore, LGR5 may play a crucial role in the carcinogenesis and tumorigenesis. In this study, we investigated the possibility of LGR5 as shared common markers by CSCs and normal stem cells, furthermore to address the correlation among LGR5, CD44 and CD133. Material and Methods: We used surgical specimens of cancer tissue to digest it into single cell suspension. The cells were immuno-stained for flow cytometory, the antigenic profiles of CD133 and CD44 were analyzed. Furthermore, the fractionated cells were sorted and transplanted into NOD/SCID mice. The xenograft tumors were analyzed by flow cytometory again or quantitative real-time PCR (qRT-PCR). And more, total RNA isolated from colorectal cancer and adjacent normal mucosa in 202 patients with untreated colorectal cancer was prepared and complementary DNA (cDNA) was synthesized from total RNA. qRT-PCR was performed to observe the expressions of LGR5, CD44 and CD133. Results: In vivo subcutaneous transplantation showed that as few as 100 CD133+CD44+ cells from primary tumor tissue had tumorigenicity in NOD/SCID mice, where in this cell fraction LGR5 was higher positive compared with other fractions. In xenograft, proportion of LGR5, CD133 and CD44 were expanded as compared with primary cancer and adjacent normal mucosa. In 202 clinical specimens, LGR5, CD44 or CD133 was expressed strongly compared with normal mucosa (p<0.0001). However, with any single marker was not enough to predict the prognosis. Instead, combined with CD44 or CD133, the group of LGR5 over-expression showed significantly low survival rate (p<0.022). Conclusion: LGR5+, CD133+ or CD44+ cells expressed the characters of cancer stem cells in xenograft tumors as well as in primary colorectal cancers. Importantly, LGR5 is a potentially critical factor determining prognosis in clinics. 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 5210. doi:10.1158/1538-7445.AM2011-5210