ARID1B and familial pancreatic carcinoma: To determine whether the same might extend to other SWI/SNF subunits that we observed to be commonly mutated or deleted in pancreatic cancers, we used RNAi to knockdown SMARCA2 (the alternative enzymatic subunit), ARID1A or ARID1B (DNA targeting/specificity subunits) in normal HPDE cells.