Abstract Background; The patient-derived xenograft (PDX) model is likely to reflect original human cancer biology compared to cultured cell lines, since tumor tissues are directly implanted into animals. PDX models of ovarian cancer have been developed, but were not fully characterized at the molecular level, especially for clear cell carcinoma (CCC), which is more prevalent in Japan than western countries, exhibits chemoresistant phenotype and poor survival. The development of new treatment strategies and the better understanding of biology of CCC both depend on clinically relevant animal models. In particular, molecular annotated PDX models are useful for the preclinical investigation of anticancer drugs and individualized anticancer therapy. Methods; We transplanted 19 parent (primary or metastatic) tumors directly into NOG mice. The histologic characteristics were compared between parental tumors and PDX ones. Among CCC pairs, gene expression analysis, gene mutation analysis were conducted on parental tumors and corresponding PDX tumors. Response to chemotherapeutic agents was analyzed using PDX tumors of CCC, and correlated with clinical outcome. Results; Six of nineteen (31.6%) transplanted tumors could be passaged. Gene expression profiles revealed that engrafted tumors expressed more proliferation-related genes than those of non-englafted ones. Among six PDX models established, two were found to be CCC. Two PDX tumors of CCC maintained the histologic characteristics of parental CCC tumors. Gene expression profile revealed similar results between primary CCC and PDX tumors of CCC except that PDXs lost expression of immune-related genes.. Gene mutational analysis showed similar pattern between primary CCC and PDX of CCC. Drug-sensitivity test showed resistance to carboplatin in two PDX tumors of CCC, which is consistent with their clinical outcomes. Conclusions. PDXs of CCC were established and found to retain histologic and clinical features of original tumors, and can be utilized to screen new target drugs for platinum-resistant CCC. Citation Format: Hidemichi Watari, Daisuke Endo, Kouhei Honda, Mihoko Kunitomo, Toshiyuki Nomura, Noriaki Sakuragi. Establishment and characterization of patient-derived xenografts of clear cell carcinoma of the ovary [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3845. doi:10.1158/1538-7445.AM2017-3845
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