Prognostic Value of Stem Cell Quantification in Stage II Colon Cancer

BACKGROUND Cancer stem cells (CSCs) are a subset of tumor cells with capacity to self-renew and generate the diverse cells that make up the tumor. The aim of this study is to evaluate the prognostic value of CSCs in a highly homogeneous population of stage II colon cancer. METHODS One hundred stage II colon cancer patients treated by the same surgical team between 1977 and 2005 were retrospectively analyzed. None of the patients received adjuvant chemotherapy. Inmunohistochemistry expression of CD133, NANOG and CK20 was scored, using four levels: <10%, 11-25%, 26-50% and >50% positivity. Kaplan-Meier analysis and log rank test were used to compare survival. RESULTS The average patient age was 68 years (patients were between 45-92 years of age) and median follow up was 5.8 years. There was recurrent disease in 17 (17%); CD133 expression (defined by >10% positivity) was shown in 60% of the tumors, in 95% for NANOG and 78% for CK20. No correlation was found among expression levels of CD133, NANOG or CK20 and relapse-free survival (RFS) or overall survival (OS). However, a statistical significant correlation was found between established pathological prognostic factors and RFS and OS. CONCLUSIONS Stem Cell quantification defined by CD133 and NANOG expression has no correlation with RFS or OS in this cohort of Stage II colon cancer.