Haugg Anke M, Rennspiess Dorit, zur Hausen Axel, Speel Ernst-Jan M, Cathomas Gieri, Becker Jürgen C, Schrama David
Department of Pathology, GROW-School for Oncology and Developmental Biology, Maastricht UMC, Maastricht, The Netherlands.
Int J Cancer. 2014 Dec 15;135(12):2804-15. doi: 10.1002/ijc.28931. Epub 2014 May 9.
The Merkel cell polyomavirus (MCPyV) is detected in 80% of Merkel cell carcinomas (MCC). Clonal integration and tumor-specific mutations in the large T antigen are strong arguments that MCPyV is a human tumor virus. However, the relationship between viral presence and cancer induction remains discussed controversially. Since almost all studies on virus prevalence are based on PCR techniques, we performed MCPyV fluorescence in situ hybridization (FISH) on MCC to gain information about the quality of the viral presence on the single cell level. MCPyV-FISH was performed on tissue microarrays containing 62 formalin-fixed and paraffin-embedded tissue samples including all tumor grades of 42 patients. The hybridization patterns were correlated to the qPCR data determined on corresponding whole tissue sections. Indeed, MCPyV-FISH and qPCR data were highly correlated, i.e. 83% for FISH-positive and 93% for FISH-negative cores. Accordingly, the mean of the qPCR values of all MCPyV-positive cores differed significantly from the mean of the negative cores (p = 0.0076). Importantly, two hybridization patterns were definable in the MCPyV-FISH: a punctate pattern (85%) indicating viral integration, which correlated with a moderate viral abundance and a combination of the punctate with a diffuse pattern (15%), suggesting a possible coexistence of integrated and episomal virus which was associated with very high viral load and VP1 expression. Thus, MCPyV-FISH adds important information on the single cell level within the histomorphological context and could therefore be an important tool to further elucidate MCPyV related carcinogenesis.
在80%的默克尔细胞癌（MCC）中可检测到默克尔细胞多瘤病毒（MCPyV）。大T抗原中的克隆整合和肿瘤特异性突变有力地证明MCPyV是一种人类肿瘤病毒。然而，病毒存在与癌症诱发之间的关系仍存在争议。由于几乎所有关于病毒流行率的研究都基于PCR技术，我们对MCC进行了MCPyV荧光原位杂交（FISH），以获取单细胞水平上病毒存在情况的相关信息。对包含62个福尔马林固定石蜡包埋组织样本的组织微阵列进行了MCPyV-FISH检测，这些样本来自42例患者的所有肿瘤分级。杂交模式与在相应全组织切片上测定的qPCR数据相关。事实上，MCPyV-FISH和qPCR数据高度相关，即FISH阳性核心的相关率为83%，FISH阴性核心的相关率为93%。因此，所有MCPyV阳性核心的qPCR值平均值与阴性核心的平均值有显著差异（p = 0.0076）。重要的是，在MCPyV-FISH中可定义两种杂交模式：点状模式（85%）表明病毒整合，这与中等病毒丰度相关；点状模式与弥漫性模式的组合（15%），提示整合型和游离型病毒可能共存，这与非常高的病毒载量和VP1表达相关。因此，MCPyV-FISH在组织形态学背景下的单细胞水平上增加了重要信息，因此可能是进一步阐明MCPyV相关致癌机制的重要工具。
