Prognostic value of Caspase-3 expression in cancers of digestive tract: a meta-analysis and systematic review

Various studies have evaluated the relationship between Caspase-3 expression and cancers of digestive tract. However, the prognostic value of Caspase-3 expression remains unclear. Hence, a meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between Caspase-3 expression and survival of patients in gastrointestinal tract cancers. Electronic databases updated to April 12(th), 2015 were searched to obtain relevant primary articles. Twelve studies were finally included with 2402 patients of esophageal, gastric or colorectal cancers. The detection of Caspase-3 was performed by immunohistochemistry (IHC). Survival data were aggregated and quantitatively analyzed. Combined hazard ratios (HRs) suggested that Caspase-3 expression had no specific impact on the overall survival (OS) (HR=0.94, 95% CI (0.64-1.37), I(2)=79.6%, P<0.001) of cancers of digestive tract. When each subtype of gastrointestinal cancer was analyzed separately, the over-expression of Caspase-3 was associated with favorable prognosis of OS in esophageal cancer HR=0.31, 95% CI (0.09-1.09), I(2)=54.6%, P=0.138). On the contrary, high level of Caspase-3 was correlated with poor prognosis of OS in gastric cancer HR=1.53, 95% CI (0.93-2.50), I(2)=46.4%, P=0.172). However, the expression of Caspase-3 showed no relationship of OS for patients with colorectal cancer (HR=1.03, 95% CI (0.66-1.63), I(2)=0.0%, P=0.410). Furthermore, the Caspase-3 expression was an indicator of poor prognosis of recurrence-free survival (RFS) for digestive tract cancer (HR=1.65, 95% CI (1.12-2.41), I(2)=43.9%, P=0.148). More studies need to be carried out to certify the prognostic value of Caspase-3 expression for patients with digestive tract cancers.