Kuroda T, Ogiwara H, Sasaki M, et al. - By engaging multiple ARID1A-knockout cell lines and an ovarian clear cell carcinoma (OCCC) cell line panel, drugs with particular toxicity to ARID1A-deficient OCCC cells were recognized among six cytotoxic drugs utilized in conventional chemotherapy for OCCC in order to examine standard chemotherapeutic options appropriate for ARID1A-deficient individuals with OCCC. Particular sensitivity to gemcitabine was noted in ARID1A-knockout and ARID1A-deficient OCCC cells. For gemcitabine of ARID1A-deficient cells, in comparison with those of ARID1A-proficient cells, IC50 values were significantly lower. Growth of OCCC xenografts with ARID1A deficiency was hindered by the administration of gemcitabine, and in ARID1A-deficient OCCC cells, gemcitabine treatment efficiently provoked apoptosis. significantly longer progression-free survival following gemcitabine treatment was noted in three ARID1A-deficient patients with OCCC vs four ARID1A-proficient individuals with OCCC. An ARID1A-deficient case showed a climactic response to gemcitabine in the second-line treatment, that was immune to multiple cytotoxic drugs, such as paclitaxel plus carboplatin in the adjuvant and etoposide plus irinotecan in the first-line treatment. Hence, in clinical settings, ARID1A-deficient participants with OCCC could profit from gemcitabine treatment.