Association between Alpha B-crystallin expression and prognosis in patients with solid tumors: A protocol for systematic review and meta-analysis

BACKGROUND: Alpha B-crystallin (CRYAB), as a small heat shock protein, may play critical roles in the tumorigenesis and progression of several kinds of human cancers. However, the prognostic value of CRYAB in solid malignancies remains controversial. The aim of the present study was to investigate the association between CRYAB expression and clinicopathology and prognosis of solid tumor patients. METHODS: PubMed, Web of Science, EMBASE, Chinese National Knowledge Infrastructure, and WanFang databases were systematically searched to retrieve studies that investigated the prognostic value of CRYAB expression in various solid tumors. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to determine the strength of association between CRYAB expression and survival in patients with solid tumors. Odds ratios (ORs) with 95% CIs were pooled to assess the correlation between CRYAB expression and clinicopathological characteristics of patients with solid tumors. RESULTS: A total of 17 studies, including 18 cohorts with 6000 patients, were included in this meta-analysis. Our results showed that increased CRYAB expression could predict poor overall survival (HR = 1.81, 95% CI: 1.50–2.19, P < .001), disease-free survival (HR = 1.47, 95% CI: 1.16–1.86, P = .001), and disease-specific survival (HR = 1.40, 95% CI: 1.19–1.63, P < .001) in patients with cancer. Furthermore, the high expression level of CRYAB was associated with certain phenotypes of tumor aggressiveness, such as lymph node metastasis (OR = 2.46, 95% CI: 1.48–4.11, P = .001), distant metastasis (OR = 3.34, 95% CI: 1.96–5.70, P < .001), advanced clinical stage (OR = 2.24, 95% CI: 1.24–4.08, P = .008), low OS rate (OR = 4.81, 95% CI: 2.82–8.19, P < .001), and high recurrence rate (OR = 1.38, 95% CI: 1.11–1.72, P = .004). CONCLUSIONS: CRYAB may serve as a valuable prognostic biomarker and therapeutic target in human solid tumors.