High OCT4 Expression Might Be Associated with an Aggressive Phenotype in Rectal Cancer

SIMPLE SUMMARY: The oncofetal protein OCT4 is a factor that promotes self-renewal and maintenance of pluripotency of embryonic stem cells and induced stem cells, which has been linked to neoplastic processes, but its role and clinical significance in rectal cancer are unknown. Therefore, the aim of this study was to evaluate the expression of the stem cell marker OCT4 related to clinical-pathological characteristics and its clinical significance in rectal cancer patients. Protein expression of the stem cell marker OCT4 was found in rectal tumor tissue but not in adjacent non-tumor tissue, and high expression was significantly associated with phenotypical characteristics of more aggressive rectal cancer. ABSTRACT: Rectal cancer (RC) is one of the most common malignant neoplasms, and cancer stem cells (CSCs) of the intestinal tract have been implicated in its origin. The oncofetal protein OCT4 has been linked to neoplastic processes, but its role and clinical significance in RC are unknown. This study investigates the expression of the stem cell marker OCT4 related to clinical-pathological characteristics and its clinical significance in RC patients. The expression level of stem cell marker OCT4 was analyzed in 22 primary rectal tumors by western blot. The association between OCT4 protein expression and the clinical-pathological features of tumors was evaluated by χ(2) test and Fisher’s exact test. We demonstrated that the expression of the stem cell marker OCT4 was observed in tumor tissue but not adjacent non-tumor tissue. High expression of the stem cell marker OCT4 was significantly associated with histological differentiation grade (p = 0.039), tumor invasion level (p = 0.004), lymph node involvement (p = 0.044), tumor-node-metastasis (TNM) stage (p = 0.002), and clinical stage (p = 0.021). These findings suggest that high OCT4 expression is associated with a more aggressive RC phenotype, with a greater likelihood of progression and metastasis. These results shed light on the importance of targeting this CSC marker to attenuate RC progression.