ARID1A and neoplasm: Using 6 separate data sets from 6 different cancer cell lines (including 1 OCCC), only 1 cell line (cholangiocarcinoma, HuCCT1) showed a statistically significant increase in PIK3R3 in ARID1A-deficient cells (Supplemental Figure 8), suggesting that the molecular mechanisms that lead to PIK3R3 upregulation in bladder cancer cells may be uncommon in other tumor types.