RAD51 and oral cavity squamous cell carcinoma: Pan‐cancer survival analysis of RAD51 revealed that its overall survival (OS) analysis predicted poor prognosis in seven cancers: oral squamous cell carcinoma (OSCC), malignant mesothelioma (MESO), LGG, LUAD, LIHC, KIRP and BRCA; additionally, it predicted favourable prognosis in READ and thymoma (THYM) with statistical significance (p < 0.05).