Approximately half of OCCC had mutations in the SWI/SNF chromatin remodelling complex subunit ARID1A, and cross-cancer analysis of the TCGA database showed that lysine-specific histone demethylase 1 (LSD1), which regulated the chromatin landscape and gene expression by demethylating proteins such as histone H3, was highly expressed in SWI/SNF-mutated tumors. This evidence concerns the gene KDM1A and cancer.