Pelosi G, Fraggetta F, Sonzogni A, Fazio N, Cavallon A, Viale G
Divisione di Anatomia Patologica e Medicina di Laboratorio, Istituto Europeo di Oncologia, Milano, Italy.
Virchows Arch. 2000 Sep;437(3):270-4. doi: 10.1007/s004280000240.
Although considered a specific marker for Ewing's sarcoma/peripheral neuroectodermal tumour, the MIC2 gene product (CD99) has been immunolocalised in a variety of human tumours. The present study evaluated immunohistochemically the prevalence of CD99 expression in a series of 68 neuroendocrine tumours of different gastrointestinal and pulmonary sites. We now report on membrane and/or granular cytoplasmic immunoreactivity in 25% of these tumours, independent of their anatomical sites. In lung neuroendocrine tumours, CD99 was preferentially confined to typical carcinoids (P=0.009). A statistically significant relationship was observed between the number of CD99 positive cells but not the immunostaining patterns and the presence of local invasion and/or distant metastases (P<0.001). Moreover, there was a tendency for CD99-reactive tumours to show a reduced proliferative activity expressed by a Ki67 index of 2% (P=0.119). The number of CD99 immunoreactive cells or patterns of immunoreactivity did not correlate with the presence of associated clinical syndrome or particular hormonal immunostaining. Although the molecular basis underlying CD99 expression in neuroendocrine tumours is still poorly understood, our data suggest that CD99 may be involved in cell-to-cell adhesion of neuroendocrine tumour cells and in downregulation of their proliferative activity.
尽管MIC2基因产物（CD99）被认为是尤因肉瘤/外周神经外胚层肿瘤的特异性标志物，但它已在多种人类肿瘤中被免疫定位。本研究采用免疫组织化学方法评估了一系列68例不同胃肠道和肺部部位神经内分泌肿瘤中CD99表达的普遍性。我们现在报告这些肿瘤中有25%存在膜和/或颗粒状细胞质免疫反应性，与它们的解剖部位无关。在肺神经内分泌肿瘤中，CD99优先局限于典型类癌（P = 0.009）。观察到CD99阳性细胞数量（而非免疫染色模式）与局部侵袭和/或远处转移的存在之间存在统计学显著关系（P < 0.001）。此外，CD99反应性肿瘤有显示增殖活性降低的趋势，Ki67指数为2%（P = 0.119）。CD99免疫反应性细胞数量或免疫反应模式与相关临床综合征的存在或特定激素免疫染色无关。尽管神经内分泌肿瘤中CD99表达的分子基础仍知之甚少，但我们的数据表明CD99可能参与神经内分泌肿瘤细胞的细胞间黏附及其增殖活性的下调。
