Aim: To investigate the significance of Twist2 for colorectal cancer (CRC).
Methods: In this study, 93 CRC patients were included who received curative surgery in Eastern Hepatobiliary Surgery Hospital from January 1999 to December 2010. Records of patients' clinicopathological characteristics and follow up data were reviewed. Formalin-fixed, paraffin-embedded tissue blocks were used to observe the protein expression of Twist2 and E-cadherin by immunohistochemistry. Two independent pathologists who were blinded to the clinical information performed semiquantitative scoring of immunostaining. A total score of 3-6 (sum of extent + intensity) was considered as Twist2-positive expression. The expression of E-cadherin was divided into two levels (preserved and reduced). An exploratory statistical analysis was conducted to determine the association between Twist2 expression and clinicopathological parameters, as well as E-cadherin expression. Furthermore, the variables associated with prognosis were analyzed by Cox's proportional hazards model. Kaplan-Meier analysis was used to plot survival curves according to different expression levels of Twist2.
Results: Twist2-positive expression was observed in 66 (71.0%) samples and mainly located in the cytoplasm. Forty-three (46.2%) samples showed reduced expression of E-cadherin. There were no significant correlations between Twist2 expression and any of the clinicopathological parameters. However, Twist2-positive expression was significantly associated with reduced expression of E-cadherin (P = 0.040). Multivariate analysis revealed that bad M-stage [hazard ratio (HR) = 7.694, 95%CI: 2.927-20.224, P < 0.001] and Twist2-positive (HR = 5.744, 95%CI: 1.347-24.298, P = 0.018) were the independent risk factors for poor overall survival (OS), while Twist2-positive (HR = 3.264, 95%CI: 1.455-7.375, P = 0.004), bad N-stage (HR = 2.149, 95%CI: 1.226-3.767, P = 0.008) and bad M-stage (HR = 10.907, 95%CI: 4.937-24.096, P < 0.001) were independently associated with poor disease-free survival (DFS). Survival curves showed a definite trend for Twist2-negative patients to have longer OS and DFS than Twist2-negative patients, not only overall, but also for patients in different stages, especially for DFS of patients in stage III (P = 0.033) and IV (P = 0.026).
Conclusion: Our data suggests, for the first time, that Twist2 is a valuable prognostic biomarker for CRC, particularly for patients in stage III and IV.
Keywords: Colorectal cancer; Epithelial-mesenchymal transition; Immunohistochemstry; Prognostic biomarker; Twist2.