Abstract：
Metaplastic breast carcinoma (MBC) and gynecologic carcinosarcoma (GCS) are rare, clinically aggressive cancers that demonstrate epithelial components and mesenchymal or sarcomatoid components. In this study, we assessed PD-L1 expression and tumor-infiltrating lymphocytes (TILs) in MBC and GCS. Overall, PD-L1 positivity using the SP142 clone was seen in 50 % of MBC and 51.9 % of GCS cases, with PD-L1 expression in tumor cells significantly higher in MBC cases (p = 0.034), and PD-L1 expression in immune cells similar in MBC and GCS cases. PD-L1 expression was significantly higher in epithelial components than in mesenchymal components in both MBC and GCS cases (p = 0.0005). TILs were low in the majority of MBC and GCS cases (≥ 10 %) and generally correlated with PD-L1 expression; however, many PD-L1 positive cases with low TILs were seen. PD-L1 expression using the 22C3 clone was additionally assessed, with positivity seen in 62.9 % of MBC cases and 30 % of GCS cases. Concordance between SP142 and 22C3 results was seen in 62.5 % of MBC cases and 80 % of GCS cases. Overall, our findings suggest that a subset of MBC and GCS cases may benefit from immune checkpoint inhibitor therapy. Our findings also illustrate unique aspects of PD-L1 expression patterns in these tumors which may harbor additional prognostic and therapeutic significance.
摘要：
化生性乳腺癌（MBC）和妇科癌肉瘤（GCS）是罕见的，表现为上皮成分和间充质或肉瘤样成分的临床侵袭性癌症。在这项研究中,我们评估了MBC和GCS中PD-L1的表达和肿瘤浸润淋巴细胞（TIL）。总的来说,使用SP142克隆的PD-L1阳性在50%的MBC和51.9%的GCS病例中可见,与PD-L1在肿瘤细胞中的表达显著高于MBC病例（p=0.034），在MBC和GCS病例中，免疫细胞中PD-L1的表达相似。在MBC和GCS病例中，上皮成分中的PD-L1表达明显高于间质成分（p=0.0005）。在大多数MBC和GCS病例中TIL较低（≥10%），并且通常与PD-L1表达相关；然而，观察到许多低TIL的PD-L1阳性病例.另外评估了使用22C3克隆的PD-L1表达，62.9%的MBC病例和30%的GCS病例呈阳性。在62.5％的MBC病例和80％的GCS病例中，SP142和22C3结果一致。总的来说,我们的研究结果表明,一部分MBC和GCS病例可能受益于免疫检查点抑制剂治疗.我们的发现还说明了这些肿瘤中PD-L1表达模式的独特方面，这可能具有额外的预后和治疗意义。
