The overexpression of phosphorylated signal transducer and activator of transcription 3 (p-stat3) was detected in a variety of human tumors. The published studies on p-stat3 expression among gastric carcinoma patients remain controversial.
In order to clarify the prognosis value of p-stat3 with overall survival and its association with clinicopathological characteristics in gastric carcinoma, we performed a systematic review and meta-analysis.
Eligible studies were retrieved by searching PubMed, Embase, Cochrane library, and Chinese biomedical literature service system databases.
Studies described the association between p-stat3 expression and clinicopathological characteristics and overall survival in gastric carcinoma patients; p-stat3 expression was detected by immunohistochemistry (IHC).
Odds ratio (OR) and hazard ratio (HR) were considered as a measure of evaluating the association in meta-analysis; I2 was used to assess the heterogeneity across studies; publication bias was assessed with funnel plot, Egger test, and Begg test.
Twenty-three studies including 2872 patients which evaluated the p-stat3 expression by IHC in gastric carcinoma were included. The pooled HR (HR = 2.02, 95% CI: 1.49–2.73, P < 0.00001) indicated that the increased p-stat3 expression was significantly associated with poor overall survival. In addition, when we investigated the association between p-stat3 overexpression and clinicopathological characteristics of gastric carcinoma, we found that the increased p-stat3 expression was significantly associated with tumor differentiation (poorly vs well-moderately: OR = 3.70, 95% CI: 1.98–6.93, P < 0.0001) and lymph node metastasis (present vs absent: OR = 2.40, 95% CI: 1.28–4.50, P = 0.007).
The different type of primary antibody was used; the assessment methods of p-stat3 positive expression were defined differently; the locations of p-stat3 expression were different; the method of extrapolating HR from Kaplan–Meier survival curves did seem to be less reliable than when HR was extracted directly from literatures; sample sizes, the age of patients, and the follow-up durations are different.
In conclusion, our meta-analysis indicates that the increased p-stat3 expression may be not only predict poor prognosis, but also be associated with worse tumor differentiation and lymph node metastasis in patients with gastric carcinoma.