The effect of mutant TP53 on patient overall survival was larger in studies that had adjusted their analyses for tumour stage (HR 1.95, 95% CI 1.41 to 2.66, p≤0.0001, 7 studies, 430 patients, I2=0%; see online supplementary figure S4) compared with the estimates from studies that reported unadjusted risk estimates (HR 1.22, 95% CI 0.88 to 1.70, p=0.24, 9 studies, 458 patients, I2=38%). This evidence concerns the gene TP53 and neoplasm.