20.500.12556/DiRROS-15559 BAP1-defficient breast cancer in a patient with BAP1 cancer syndrome BAP1 cancer syndrome is a rare and highly penetrant hereditary cancer predisposition. Uveal melanoma, mesothelioma, renal cell carcinoma (RCC) and cutaneous melanoma are considered BAP1 cancer syndrome core cancers, whereas association with breast cancer has previously been suggested but not confirmed so far. In view of BAP1 immunomodulatory functions, BAP1 alterations could prove useful as possible biomarkers of response to immunotherapy in patients with BAP1-associated cancers. We present a case of a patient with BAP1 cancer syndrome who developed a metastatic breast cancer with loss of BAP1 demonstrated on immunohistochemistry. She carried a germline BAP1 likely pathogenic variant (c.898_899delAG p.(Arg300Glyfs*6)). In addition, tumor tissue sequencing identified a concurrent somatic variant in BAP1 (partial deletion of exon 12) and a low tumor mutational burden. As her triple negative tumor was shown to be PD-L1 positive, the patient was treated with combination of atezolizumab and nab-paclitaxel. She had a complete and sustained response to immunotherapy even after discontinuation of nab-paclitaxel. This case strengthens the evidence for including breast cancer in the BAP1 cancer syndrome tumor spectrum with implications for future cancer prevention programs. It also indicates immune checkpoint inhibitors might prove to be an effective treatment for BAP1-deficient breast cancer. BAP1 breast cancer hereditary cancer syndromes immunotherapy BAP1 rak dojke dedni raki imunoterapija true false true Springer Angleški jezik Slovenski jezik by Authors Neznano 2022-09-17 03:40:06 2022-09-19 10:04:54 2022-09-20 03:35:26 0000-00-00 00:00:00 2022 0 0 str. 921–927 Vol. 29 2022 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2022-04-05 618.1 1340-6868 10.1007/s12282-022-01354-0 104001539 RAZ_Blatnik_Ana_2022.pdf RAZ_Blatnik_Ana_2022.pdf 1 E522C712A5F7E5EC886C5E2CD9634B5E ab8ea2efc4ea79f3e6c0c7e76d5947848092ba3009fcce3acb21408b29c618ae 2a14682c-37e1-11ed-bea5-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=20581 Onkološki inštitut Ljubljana 0 0 0