Department of Tumor Pathology and Pathomorphology, Oncology Center, Prof. Franciszek Łukaszczyk Memorial Hospital, Bydgoszcz ul. Romanowska, 85-796, Bydgoszcz, Poland.
Department of Obstetrics, Gynaecology and Oncology, Chair of Pathomorphology, Placentology, and Clinical Hematopathology, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Torun, Torun, Poland.
Clin Exp Med. 2023 Dec;23(8):5121-5127. doi: 10.1007/s10238-023-01190-2. Epub 2023 Oct 7.
PD-L1 expression is known to predict the benefits of immune checkpoint inhibitor therapy for triple-negative breast cancer (TNBC). We examined whether the PD-L1 expression evaluated in biopsy specimens accurately reflects its expression in the whole tumor. Immunohistochemistry was performed on 81 biopsy and resection specimens from patients with TNBC to determine their PD-L1 status. We found PD-L1-positive tumors in 23 (28%) biopsy specimens and primarily PD-L1-negative tumors in 58 (72%). The PD-L1 status was reevaluated in matching postoperative specimens of primarily PD-L1-negative tumors. Of them, 31% (18/58) were positive, whereas 69% (40/58) were negative. Considering the pre- and postoperative analyses, 41 (51%) patients had PD-L1-positive tumors, while 40 had PD-L1-negative tumors. We found 18 (22%) more PD-L1-positive tumors while examining the resection specimens compared to biopsies, and the difference was statistically significant (p = 0.0038). Diagnostic biopsies do not fully reflect the PD-L1 expression in TNBC. Our results suggest that a significant subset of TNBC patients may be misclassified as PD-L1-negative and disqualified from anti-PD-L1 therapy.
PD-L1 表达被认为可以预测三阴性乳腺癌（TNBC）免疫检查点抑制剂治疗的获益。我们研究了活检标本中评估的 PD-L1 表达是否准确反映了整个肿瘤的表达。对 81 例 TNBC 患者的活检和切除标本进行了免疫组织化学检测，以确定其 PD-L1 状态。我们发现 23 例（28%）活检标本中有 PD-L1 阳性肿瘤，58 例（72%）主要为 PD-L1 阴性肿瘤。对主要为 PD-L1 阴性肿瘤的匹配术后标本重新评估 PD-L1 状态。其中，31%（18/58）为阳性，69%（40/58）为阴性。考虑到术前和术后分析，41 例（51%）患者有 PD-L1 阳性肿瘤，40 例有 PD-L1 阴性肿瘤。与活检相比，我们在检查切除标本时发现了 18 例（22%）更多的 PD-L1 阳性肿瘤，差异具有统计学意义（p=0.0038）。诊断性活检不能完全反映 TNBC 中的 PD-L1 表达。我们的结果表明，相当一部分 TNBC 患者可能被错误地归类为 PD-L1 阴性，并被排除在抗 PD-L1 治疗之外。
