Uchi Hiroshi
Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Front Oncol. 2018 Mar 6;8:48. doi: 10.3389/fonc.2018.00048. eCollection 2018.
Merkel cell carcinoma (MCC) is a rare but aggressive skin cancer with frequent metastasis and death. MCC has a mortality rate of 30%, making it more lethal than malignant melanoma, and incidence of MCC has increased almost fourfold over the past 20 years in the USA. MCC has long been considered to be an immunogenic cancer because it occurs more frequently in immunosuppressed patients from organ transplant and HIV infection than in those with immunocompetent. Chronic UV light exposure and clonal integration of Merkel cell polyomavirus (MCPyV) are two major causative factors of MCC. Approximately 80% of MCC are associated with MCPyV, and T cells specific for MCPyV oncoproteins are present in the blood and tumors of patients. Several studies have shown that a subset of MCCs express PD-1 on tumor-infiltrating lymphocytes and express PD-L1 on tumor cells, which suggests an endogenous tumor-reactive immune response that might be unleashed by anti-PD-1 or anti-PD-L1 drugs.
默克尔细胞癌（MCC）是一种罕见但侵袭性强的皮肤癌，常发生转移且致死率高。MCC的死亡率为30%，比恶性黑色素瘤更具致命性，在美国，MCC的发病率在过去20年里几乎增长了四倍。长期以来，MCC一直被认为是一种免疫原性癌症，因为它在器官移植和HIV感染的免疫抑制患者中比免疫功能正常的患者更常见。慢性紫外线照射和默克尔细胞多瘤病毒（MCPyV）的克隆整合是MCC的两个主要致病因素。大约80%的MCC与MCPyV有关，患者的血液和肿瘤中存在针对MCPyV癌蛋白的T细胞。多项研究表明，一部分MCC在肿瘤浸润淋巴细胞上表达PD-1，在肿瘤细胞上表达PD-L1，这表明可能存在一种内源性肿瘤反应性免疫反应，抗PD-1或抗PD-L1药物可能会激发这种反应。
