青少年肾细胞癌的临床病理及分子遗传学研究

目的 探讨青少年肾细胞癌的临床病理特征、遗传学改变、鉴别诊断及预后.方法 对46例青少年肾细胞癌进行光镜观察及免疫组织化学染色,随访并复习相关文献.对46例肿瘤进行von Hippel-Lindau(VHL)基因区域杂合性缺失(LOH)及VHL基因突变筛查.结果 共诊断19例Xp11.2易位/TFE3基因融合相关性肾癌(Xp11 RCC)、9例透明细胞癌、17例乳头状肾细胞癌(PRCC)和1例不能分类肾细胞癌.19例Xp11 RCC均TFE3阳性,而TFEB阴性.8例肿瘤具有巢状和乳头状结构形态类似t(X;17)ASPL-TFE3型肾癌,6例肿瘤组织学类似t(X;1)PRCC-TFE3型肾癌,4例肿瘤形态像透明细胞癌,1例肿瘤组织学形态文献中未被检索到,表现为细胞核呈毛玻璃样,核仁不明显,可见核沟,肿瘤间质见大量黏液.LOH及VHL突变检测结果显示,仅1例透明细胞癌和1例2型PRCC存在LOH,并且该2型PRCC的VHL基因的一个剪切位点存在胚系突变,553+5 G→C.其余45例均未检测出VHL突变.统计学分析表明TFE3阳性肾细胞癌比TFE3阴性肾细胞癌更倾向于高病理分期(pT3/pT4),并且预后较差(P=0.035).结论 青少年肾细胞癌表现出不同的组织学形态以及分子遗传学背景.其中Xp11 RCC为最常见的肾癌亚型.TFE3阳性肾细胞癌的预后要差于TFE3阴性肾细胞癌.

Clinicopathologic and molecular genetic study of renal cell carcinoma occurring in teenagers

Objective To investigate clinicopathological features, molecular genetic characteristics,differential diagnoses and prognosis of renal cell carcinoma in teenagers. Methods Microscopic and immunohistochemical features of 46 cases of renal cell carcinomas in teenagers were reviewed along with the clinical follow-up data. Loss of heterozygosity (LOH) , analysis of von Hippel-Lindau (VHL) gene and screening for VHL gene mutations were performed in all of the tumors. Results There were 19 Xp11.2translocations/TFE3 gene fusions renal clear cell carcinomas (Xp11 RCCs), 9 chromophobe renal cell carcinomas (CCRCCs), 17 papillary renal cell carcinomas (PRCCs), and 1 unclassified renal cell carcinoma (RCC). All of the 19 Xp11.2 translocation RCCs showed a moderate to strong immunoreactivity for TFE, however, no TFEB expression was obtained. There were 4 histological patterns in the Xp11 RCCcases including: 8 tumors possessing a nested to papillary architecture resembling to the t(X;17) ASPLTFE3 phenotype; 6 tumors possessing a morphologic feature like the t(X;1) PRCC-TFE3 phenotype;4 cases morphologically resembling to clear cell RCC; and 1 Xpl1 RCC case, with a special morphologic feature not searched yet in the literature, including a ground glass appearance of the nuclei accompanying occasionally with grooves on the nuclear surface; nucleoli inconspicuous with accumulation of abundant mucin-like substance in the stroma. VHL gene analysis revealed deletions at 3p25-26 in one clear cell RCC and one papillary type 2 RCC. The papillary type 2 RCC had also a family history of VHL disease, with a germline G→C mutation at a splicing site of position 553 + 5. There were no VHL mutations detected in the remaining 45 RCCs. Statistical analysis of tumor stage and outcome revealed that TFE + RCCs of teen-agers were more frequently associated with a higher pT3/pT4 stage and a poorer outcome than that of the TFE-RCCs(P＜0.05). Conclusions RCCs of the teenagers have a different morphologic spectrum and genetic background from the RCCs seen in adults. Among RCCs of the teen-agers, Xp11.2 translocation tumors are the most common RCCs and have a poorer prognosis than that of the TFE-RCCs.