Objective: To investigate MAML2 gene-translocation in primary pulmonary mucoepidermoid carcinoma (PMEC) and pulmanary adenosquamous carcinoma, and the optimal diagnostic immunohistiochemical (IHC) panel in distinguishing PMEC from adenosqumous carcinoma. Methods: Twenty-four cases of PMEC and 44 adenosqumous carcinoma diagnosed in the Guangdong General Hospital were tested for MAML2 translocation by fluorescent in-situ hybridization (FISH) using tissue array. An IHC panel including TTF1, Napsin A, CK5/6, p63, p40 and Ki-67 was performed on the cohort. The clinical data for all cases were collected and all PMEC patients had follow-up information. Results: The patients' age ranged form 6 to 73 years, with a median age of 32 years. The male to female ratio was 1.4∶1.0. MAML2 translocation was found in 16/24 (66.7%) cases of PMEC whereas all 44 cases adenosqumous carcinoma were negative for translocation. All the cases of the PMEC were negative for TTF1 and Napsin A but positive for CK5/6, p63 and p40 in the intermediate cells and epidermal-like cells. In most PMEC cases, the Ki-67 expression index was lower than 10%. In contrast, most cases of adenosqumous carcinomas expressed TTF1 and Napsin A in the adenomatous component and CK5/6, p63 and p40 in the squamous component, which expression pattern was different from that of PMEC. Based on IHC staining, 2 cases of highly invasive ALK-positive adenocarcinoma mimicing PMEC were also found in the study. Conclusions: MAML2 gene translocation can be detected in about two-third of PMEC. Translocation of MAML2 gene and lower morphology grading are associated with good prognosis. The combined use of IHC antibodies panel is helpful to distinguish PMEC from the adenosqumous carcinoma and adenocarcinoma mimicing PMEC.
目的： 了解肺原发黏液表皮样癌（MEC）和形态相似的肺腺鳞癌中的MAML2基因易位情况及其对诊断、预后的意义。 方法： 利用组织芯片对2007年至2016年间广东省人民医院诊断的24例肺原发MEC和44例肺腺鳞癌进行MAML2基因易位的荧光原位杂交（FISH）检测，并进行包括甲状腺转录因子1（TTF1）、Napsin A、细胞角蛋白（CK）5/6、p63、p40、Ki-67等在内的免疫组织化学套餐检测。收集所有临床资料，随访所有的肺原发MEC患者。 结果： 肺原发MEC患者的年龄分布为6~73岁，中位年龄32岁。男女比例为1.4∶1.0。肺原发MEC中MAML2基因易位检出率为66.7%（16/24），而所有的肺腺鳞癌中均未检出MAML2基因易位。MAML2基因易位、年轻、组织学低级别与预后好相关。所有肺MEC组织切片均不表达TTF1和Napsin A，特征性的于中间细胞和表皮样细胞区域表达CK5/6、p63和p40。大多数肺原发MEC Ki-67阳性指数普遍低于10%。而肺腺鳞癌组中，大部分腺癌的成分表达TTF1和Napsin A，鳞癌成分表达CK5/6、p63和p40，表达模式与MEC不同。免疫组织化学套餐的应用鉴别出形态类似于MEC的高度侵袭性ALK阳性的腺癌。 结论： 约2/3的肺原发MEC可检测到MAML2基因易位。MAML2基因发生易位、组织学低级别等因素与预后好相关。套餐式免疫组织化学抗体联合应用，有助于鉴别肺原发MEC和腺鳞癌、形态类似MEC的腺癌。.
Keywords: Lung neoplasms; MAML2 Gene translocation; Mucoepidermoid tumor; Translocation,genetic.