The MYBL2 gene plays an important role in the genesis and progression of tumors; however, few studies to date have defined the role of this gene in colorectal cancer (CRC). The aim of this study was to determine the relationship between MYBL2 and the prognosis of patients with CRC and to determine the possible effect of MYBL2 on colorectal carcinogenesis. Solid CRC tissues (n=180) preserved with RNAlater were collected to examine the mRNA levels of MYBL2 by real-time quantitative PCR (RT-qPCR). Formalin-fixed, paraffin-embedded (FFPE) blocks of CRC tissues (n=97) and adjacent noncancerous tissues (ANCTs, n=104) were obtained to detect MYBL2 protein levels by immunohistochemistry (IHC). siRNA was used to downregulate MYBL2 expression in the SW480 cell line to detect changes in proliferation, cell cycle progression, apoptosis, migration and invasion. The protein levels of MYBL2 were significantly higher in CRC tissues compared with ANCTs (P<0.05). Kaplan-Meier survival curves indicated that disease-free survival (DFS) was significantly worse in CRC patients in whom MYBL2 was overexpressed (at both the mRNA and protein levels) compared with patients not overexpressing MYBL2. Cox multivariate analysis revealed MYBL2 overexpression as an independent prognostic factor for poor patient survival. In addition, siRNA downregulation of MYBL2 suppressed SW480 cell proliferation, delayed cell cycle progression and induced apoptosis; however, changes in cell migration were minor. Western blot analysis demonstrated an association between MYBL2 expression and that of MMP9, Vimentin, and E-cadherin. MYBL2 is overexpressed in CRC and may therefore play an important role in tumourigenesis.
Keywords: MYBL2; apoptosis; cell cycle; colorectal carcinoma; epithelial to mesenchymal transition; prognosis; proliferation.