{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T19:34:27Z","timestamp":1785180867790,"version":"3.55.0"},"reference-count":45,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T00:00:00Z","timestamp":1774483200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:p>\n                    Small-cell transformation is a clinically resistant mechanism against epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in lung adenocarcinoma (LUAD). It often leads to poor outcomes and limited treatment options. This case report describes an advanced case of LUAD with an EGFR exon 19 deletion and a\n                    <jats:italic>BRCA2<\/jats:italic>\n                    mutation. After failing several therapies, the disease progressed to a histologically confirmed small-cell lung cancer (SCLC) phenotype. In this case, treatment with olaparib (150 mg\/day), combined with temozolomide (50 mg\/day) and atezolizumab for two cycles, resulted in a partial tumor response. The patient experienced grade IV myelosuppression, consistent with a previous episode of severe haematologic toxicity during chemotherapy. This case highlights the potential value of combining olaparib, temozolomide, and immune checkpoint inhibition as a therapeutic strategy for\n                    <jats:italic>BRCA2<\/jats:italic>\n                    -mutated small-cell transformation arising from LUAD. However, significant haematologic adverse effects require careful monitoring.\n                  <\/jats:p>","DOI":"10.3389\/fonc.2026.1767999","type":"journal-article","created":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T05:29:24Z","timestamp":1774502964000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Case Report: Olaparib combined with temozolomide and atezolizumab in a case of BRCA2-mutated small-cell transformation of lung adenocarcinoma"],"prefix":"10.3389","volume":"16","author":[{"given":"Meiyuan","family":"Liu","sequence":"first","affiliation":[{"name":"Department of Medical Oncology, Zhangjiajie City People\u2019s Hospital","place":["Zhangjiajie, Hunan, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pei","family":"Gao","sequence":"additional","affiliation":[{"name":"Department of Medical Oncology, Zhangjiajie City People\u2019s Hospital","place":["Zhangjiajie, Hunan, 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