Comprehensive analysis of the clinical significance of inducing pluripotent stemness-related gene expression in colorectal cancer cells

Background: We previously determined that cancer stem-like cells may influence the susceptibility of colorectal cancer (CRC) cells to chemotherapeutic agents. Although Takahashi and Park identified a set of induced pluripotent stem cell (iPS)-related genes required for normal stem cell maintenance, the precise role of iPS-related gene expression in CRC pathogenesis remains to be determined. The purpose of this study was to clarify the clinical relevance of "stemness"-regulating gene expression in CRC cases. Materials and methods: Cancer cells were excised from tissues of 79 CRC cases by laser microdissection (LMD), and quantitative RT-PCR was used to evaluate expression levels of the iPS-related genes c-MYC, SOX2, OCT3/4, LIN28, KLF4, and NANOG, and to identify any associations between their expression and clinicopathological CRC progression. Results: We found that LIN28 expression is significantly associated with lymph node metastasis (p = 0.018) and Dukes stage (p = 0.0319). SOX2expression is also correlated with lymph node metastasis. Furthermore, the ten cases with Dukes D disease expressed significantly higher levels of SOX2transcript than the other 69 cases (p = 0.0136). In contrast, KLF4 expression was inversely related to Dukes stage. Expression of c-MYC, OCT3/4, and NANOG did not appear to have clinical relevance in CRC cases. Conclusion: The present analysis strongly suggests that altered expression of several iPS-related genes plays a role in CRC pathogenesis.