ARID1A and urothelial carcinoma: Alterations in ARID1A may be diverse and have been observed in a variety of cancer types, including urothelial carcinoma (Dugas et al. 2019), gastric cancer (Kim et al. 2019) and lung cancer (Huang et al. 2015; Naito et al. 2019) and the variants of ARID1A gene could also be detected through liquid biopsy even for cancers of unknown primary (Laprovitera et al. 2021) as well.