Abstract: ObjectiveTo study dynamic expression of Oct4 during development of colorectal cancer (CRC) and investigate the association between Oct4 expression and prognosis of patients with CRC. MethodsCRC tissues, matched nontumor tissues and colonic polyp tissues were collected and Oct4 expressions were analyzed by quantitative reverse transcriptionpolymerase chain reaction (qRTPCR), flow cytometry analysis (FCM) and immunohistochemistry (IHC). Medical records of patients with CRC were reviewed. Clinicopathological analysis was performed to assess the association between Oct4 expression and certain clinicopathological parameters. KaplaneMeier survival curve was conducted to evaluate association between Oct4 expression and survival time of patients with CRC. ResultsThe results of qRTPCR showed that the relative expressions of Oct4 mRNA in matched nontumor, colonic polyp and CRC tissues were (0.23±0.16)×10-5, (1.19±0.76)×10-5 and (3.79±1.94)×10-5 respectively, with a significant difference (F=8.633, P=0.001). IHC analysis displayed that the positive expression ratios of Oct4 in matched nontumor tissues, colonic polyp tissues and CRC tissues were 4.43%, 12.68% and 40.51% respectively, and a significant difference was discovered among them (χ2=66.311, P<0.001). Oct4 expression in CRC was significantly correlated with pathological stage (χ2=7.248, P=0.007), lymph node metastasis (χ2=4.888, P=0.027), distant metastasis (χ2=5.732, P=0.017) and TNM stage (χ2=4.174, P=0.041). KaplanMeier survival curve analysis demonstrated that Oct4 positive cases had a shorter median survival time (37.0 months) compared with Oct4 negative cases (76.0 months), with a significant difference (χ2=14.050, P=0.001). ConclusionThe expression of Oct4 is stepwise increased during development of CRC. The abnormal expression of Oct4 may play certain roles in the development of CRC. Oct4 may be an important biomarker for the clinical diagnosis, assessment of disease and prognosis in CRC.

Key words: Colorectal neoplasms, Colonic polyps, Oct4