Prognostic Value of Stem Cell Quantification in Stage II Colon Cancer

ABSTRACT Background Cancer stem cells (CSCs) are a subset of tumor cells with capacity to self-renew and generate the diverse cells that comprise the tumor. They are considered cancer (Ca) initiating cells responsible for tumor recurrence and maintenance. These cells express pluripotency markers (CD133 and NANOG) and do not express markers of differentiation as cytokeratin 20 (CK20). The potential prognostic value of CSCs in colorectal cancer has been studied with conflicting results. However some of these series were based on heterogeneous situations, involving rectal and colon cancer (CC) and different tumor stages (I-IV). The aim of this study is to evaluate the prognostic value of CSCs in a highly homogeneous population of stage II CC. Methods One hundred stage II CC patients (pts) treated by the same surgical team at Ramon y Cajal University Hospital between 1977 and 2005 were retrospectively analyzed. None of the pts received adjuvant chemotherapy. Inmunohistochemistry expression of CD133, NANOG and CK20 was scored on paraffin sections using four levels: 50% positivity. Kaplan-Meier analysis and log rank test were used to compare survival. Results Median age: 68 years (45-92). Median follow up: 5.8 years. Recurrent disease: 17 (17%). Expression of CD133 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 CK 20 and relapse-free survival (RFS) and overall survival (OS). Conclusions Stem Cell quantification defined by CD133 and NANOG expression has no correlation with RFS or OS in this cohort of Stage II CC. Therefore, our results suggest that CSCs may not play a major role in early phases of CC. Disclosure All authors have declared no conflicts of interest.