RBM39 and head and neck squamous cell carcinoma: From the analysis of RBM39 expression in pan‐cancer, it was found that RBM39 showed high expression in six tumours, including cholangiocarcinoma (CHOL), rectum adenocarcinoma (READ), head and neck squamous cell carcinoma (HNSC), lung squamous cell carcinoma (LUSC), kidney clear cell carcinoma (KIRC) and kidney papillary cell carcinoma (KIRP).