As an alternative subunit to ARID1A, ARID1B shares high homology with it but may play a distinct role in tumorigenesis, it is possible that ARID1A and ARID1B have opposing functions in tumour development, with ARID1A crucially inhibiting cell proliferation while ARID1B appears to promote cell proliferation and maintain stem cell characteristics [21]. The gene discussed is ARID1A; the disease is neoplasm.