SMARCA1 and neoplasm: ARID1A and other members of the SWI/SNF complex have been shown to have tumor suppressor functions, as loss of ARID1A leads to increased cellular proliferation, de-differentiation, and inhibition of apoptosis.22 Loss of ARID1A or other SWI/SNF members may also lead to transcriptional dysfunction, including disruption of nucleosome sliding activity, affecting the ability of the RNA polymerase II complex to bind promoters.