ARID1A and ARID1B are two members of the ARID1 subfamily and are subunits of the SWI/SNF chromatin remodeling complex, which is instrumental in its role as a tumor suppressor as evidenced from the studies understanding how mutation of ARID1A in different organ-type cancers facilitates oncogenic transformation [15,37]. The gene discussed is SMARCA1; the disease is neoplasm.