P-234 - The Intestinal Stem Cell Marker SOX9 Predicts Relapse of Stage II Colon Cancer Patients

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Colon Cancer
Translational Research
Presenter M. Espersen
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors M. Espersen1, J. Troelsen1, D. Linnemann2, M. Alamili3, E. Hogdall2
  • 1Roskilde University, Roskilde/DK
  • 2Herlev University Hospital, Herlev/DK
  • 3Køge University Hospital, Køge/DK

Abstract

Introduction

Approximately 25% of patients with stage I and stage II colon cancer relapse. To this date no optimal biomarkers can identify colon cancer patients with elevated risk of relapse. The aim of this study was to investigate the intestinal stem cell marker, SOX9, as a biomarker for identification of stage II colon cancer patients with high risk of relapse.

Methods

Formalin fixed paraffin-embedded tissues of primary tumors from 147 patients diagnosed with stage II colon cancer from January 2005 to August 2008 were consecutively included. The samples were further stratified by location of tumor and tumor mismatch repair (MMR) deficiency. MMR deficiency was analyzed by immunohistochemistry (IHC) and a methylation assay. The level of SOX9 was investigated by IHC both at the invasive front of the primary tumor and at the luminal surface.

Results

25% of the included patients had a relapse of their cancer. MMR deficiency was shown in 22% of the tumors and for the majority due to methylation of the MLH1 promoter. Tumor MMR deficiency was negatively associated with relapse (p = 0.02). Low levels of SOX9 at the invasive front of the tumor were an independent predictor of relapse (p = 0.03) when adjusted for age, gender, postoperational chemotherapy, pathological risk factors, and MMR deficiency. SOX9 levels at the luminal surface of the tumors were not associated with relapse (p = 0.52).

Conclusion

MMR deficiency is negatively associated with relapse of stage II colon cancer patients. Low level of SOX9 at the invasive front of the primary tumor is an independent predictor of relapse of stage II colon cancer patients and may justify more intensive follow-up of these patients.