Additionally, 35.8% of CCA samples harbored a mutation in at least one of three DDR genes (ARID1A, BAP1 or ATM). Mutations in ARID1A have been previously reported in up to 14% of CCA samples [28] and its deficiency hypothesized to sensitize cancer cells to PARPi [29]. The gene discussed is ARID1A; the disease is cholangiocarcinoma.