Alterations of Tumor Suppressor Genes Expression in Colorectal Cancer: Their Impact on Progression and Prediction of Patients Outcome

Background: Deregulation of tumor suppressor genes as APC, DCC and SMAD2 are related to tumorgenesis thus we aimed to investigate their expression among colorectal cancer to validate their relation with clinicopathological factors and the clinical outcome for CRC patients.

Materials and Methods: Formalin-fixed paraffin samples from 115 colorectal cancer were investigated for APC, DCC and SMAD2 gene expression using quantitative PCR (QPCR) and their levels were analyzed versus clinicopathological factors and the overall survival (OS) of colorectal cancer patients.

Results: A significant relation was reported between DCC and SMAD2 gene expression with clinical stages as they reported decrease expression among those with stage III. The three investigated genes were decreased significantly with poor histological differentiation colorectal cancer patients. The correlations between the expressions of the investigated genes revealed a significant correlation between SMAD2 and APC as well as between SMAD2 and DCC. Moreover patients with mean levels below and equal their expression values showed a considerable difference with OS.

Conclusion: Gene expression of tumor suppressor genes APC, DCC and SMAD2 were significantly related to differential grading and patient's outcome thus pointing out their potential role as predictive markers for prognosis of colorectal cancer.