Serum amyloid A protein in cancer prognosis: a meta-analysis and systematic review

BACKGROUND: Published studies showed divergent results of the prognostic value of serum amyloid A protein (SAA) in patients with different cancers. Therefore, we conducted this meta-analysis so as to assess the association between SAA and cancer prognosis. METHODS: A comprehensive search was conducted to identify the literatures working over SAA and survival in patients with cancers published until January 2020. Sufficient data for assessing overall survival in cancers were extracted descriptively and quantitatively from the studies and a pooled odds ratio was calculated using the Mantel-Haenszel fixed-effect or random-effect model. RESULTS: Ten eligible papers were identified by two reviewers independently, including 4 studies that evaluated renal cell carcinoma (RCC), 2 studies evaluated lung cancer and the other 3 studies evaluated melanoma, gastric cancer and different cancers. Elevated SAA expression and shorter overall survival (OS) had a statistically significant relation [pooled 1-year OR was 5.07, 95% confidence interval (CI), 3.71–6.94, Q=9.15, I(2)=0%; pooled 3-year OR was 4.21, 95% CI, 3.18–5.56, Q=14.94, I(2)=46%; pooled 5-year OR was 5.69, 95% CI, 2.66–12.18, Q=24.83, I(2)=80%]. Subgroup analysis of RCC patients showed remarkable association between SAA and shorter OS (pooled 1-year OR =4.76, 95% CI, 3.00–7.56, Q=4.18, I(2)=4%; pooled 3-year OR =4.89, 95% CI, 3.06–7.81, Q=2.88, I(2)=0%). CONCLUSIONS: High SAA status is correlated with an unfavorable OS in different cancers, especially in RCC, and digestive cancer.