Abstract 5197: Identification of prognostic cancer stem cell marker profiles in aggressive metastatic colorectal cancer

Background: Despite recent advances in screening and treatment, metastatic colorectal cancer (CRC) remains a leading cause of cancer-related death in the United States. A subset of patients with metastatic disease to the liver may achieve long-term survival with metastasectomy. However, the majority of patients with liver metastases have a median survival of approximately 2 years despite treatment. Several studies have proposed that cancer stem cells (CSC) may be linked to metastasis, treatment resistance and recurrence, but to date, no one has examined whether the expression of CSC markers can be prognostic indicators of recurrence and overall survival in metastatic CRC. Methods: Formalin-fixed, paraffin-embedded metastatic CRC tissue samples were obtained from patients treated with metastasectomy of liver disease. Using standard immunohistochemical techniques, tissue samples were stained with antibodies to previously characterized CSC markers CD166, CD133, CD44 and CD26. Cellular expression patterns for solitary and multiple CSC markers were analyzed using an automated open source image quantification program (CellProfiler 2.0). Expression profiles were then correlated to patient outcomes (disease recurrence and overall survival). Results: Variable expression of CSC markers was seen between long- and short-term survival as well as rate of recurrence. Patients with an increased overall survival showed a higher level of CD44 expression. Co-expression of CD44 and CD166 correlated to increased disease-free survival. Conclusion: In this study, we identify a subset of CSC markers that correlates to disease behavior and tumor biology in metastatic CRC. Further delineation of CSC profiles may give valuable clues to therapeutic resistance as well as offer new therapeutic targets in the treatment of this disease. 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 5197. doi:10.1158/1538-7445.AM2011-5197