Author/Editor		Blatnik, Ana; Ribnikar, Domen; Šetrajčič Dragoš, Vita; Novaković, Srdjan; Stegel, Vida; Grčar-Kuzmanov, Biljana; Boc, Nina; Perić, Barbara; Škerl, Petra; Klančar, Gašper; Krajc, Mateja
Title		BAP1-defficient breast cancer in a patient with BAP1 cancer syndrome
Type		članek
Vol. and No.		, št. Vol. 29
Publication year		2022
Volume		str. 921‐927
ISSN		1340-6868 - Breast cancer (Tokyo, Japan)
Language		eng
Abstract		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.
Keywords		BAP1 rak dojke dedni raki imunoterapija BAP1 breast cancer hereditary cancer syndromes immunotherapy