Objective: To investigate the clinicopathological significance of BRAF V600E and CTNNB1 gene mutations in adamantinomatous craniopharyngiomas (ACP) and papillary craniopharyngiomas (PCP). Methods: The retrospective study included a total of 67 craniopharyngiomas diagnosed from October 2009 to August 2018 at Xuanwu Hospital, Capital Medical University. The immunohistochemical staining for β-catenin and BRAF V600E expression, Sanger sequencing of exon 3 of CTNNB1, BRAF mutation analysis by scorpions amplification refractory mutation system (ARMS) fluorescence quantitative PCR were performed. Univariate survival analysis was used to correlate with tumor recurrence. Results: Of the 67 patients, 53 were ACPs and 14 were PCPs. Four patients underwent multiple operations and one of them presented with malignant transformation into squamous cell carcinoma. Histologically, ACPs were characterized by whorl-like cell clusters, peripheral palisaded layer, stellate reticulum, finger-shaped protrusions, ghost cells and wet keratinous substances. While PCPs usually consisted of mature squamous epithelium associated with fibrovascular stroma resulting in papillary appearance. The nuclear immunopositivity for β-catenin was observed in 73.6% (39/53) of ACPs, and it was absent in PCPs (0/14). The nuclear translocation of β-catenin usually presented at whorl-like structures or around ghost cells. Of all the cases, mutations analysis in exon 3 of β-catenin gene CTNNB1 were successful in 46 cases and 42.1% (16/38) of ACP showed CTNNB1 gene mutation, while none of the PCPs harbored CTNNB1 gene mutation (0/8). The cytoplasmic immunopositivity for BRAF V600E mutant protein was found in all PCPs (14/14) and negative in all ACPs (0/53). ARMS-PCR results showed that BRAF V600E mutations were observed in 13/14 of PCPs but not seen in ACPs (0/53). Follow-up data were available in 35 patients with duration of 2 to 120 months. Ten patients experienced recurrences after the first surgery. Upon univariate survival analysis, only subtotal excision was found to be associated with increased recurrence (P=0.032), while pathological type, postoperative radiotherapy and CTNNB1 gene mutation were not (P>0.05). Conclusions: There is significant difference in the expression of BRAF V600E and CTNNB1 genes between ACP and PCP, and their immunohistochemical and molecular detection therefore can be used in the diagnosis and differential diagnoses of craniopharyngiomas.
目的： 探讨BRAF V600E与CTNNB1基因突变在造釉细胞型颅咽管瘤（adamantinomatous craniopharyngioma，ACP）和乳头型颅咽管瘤（papillary craniopharyngioma，PCP）中的临床病理学意义。 方法： 回顾性分析2009年至2018年首都医科大学宣武医院病理科76例颅咽管瘤确诊病例，采用免疫组织化学、Sanger测序及蝎形探针扩增阻滞突变系统（scorpions ARMS）荧光定量PCR检测颅咽管瘤两个亚型中BRAF V600E基因及β-catenin编码基因CTNNB1的突变情况；分析影响颅咽管瘤复发的因素。 结果： 67例患者中，ACP 53例，PCP 14例，4例出现多次复发，1例恶变为鳞状细胞癌。镜下观察：ACP出现特征性结构：栅栏状上皮、旋涡状细胞团、星网状结构、指状突起，鬼影细胞、湿性角化物等；PCP镜下被覆形态较单一的成熟鳞状上皮，围绕纤维血管轴心呈乳头状生长。β-catenin蛋白核阳性均出现于ACP中，常位于旋涡状细胞簇或鬼影细胞周围，阳性率为73.6%（39/53），在PCP中没有表达（0/14）。Sanger检测β-catenin编码基因CTNNB1成功者46例，只在42.1%（16/38）的ACP中检测到CTNNB1基因突变，而PCP中未检出（0/8）。BRAF V600E突变型蛋白胞质阳性均出现于PCP中（14/14），而ACP中均为阴性（0/53）。ARMS-PCR结果显示，14例PCP中，BRAF V600E突变比例达13/14，而ACP中均未检出（0/53）。共35例患者获得随访资料，随访时间2~120个月（平均35个月），10例患者首次术后出现复发。单因素生存分析结果显示，只有手术未全切与肿瘤复发相关（P=0.032），而病理类型、术后放疗及CTNNB1基因突变与肿瘤复发之间相关性不明显（P>0.05）。 结论： BRAF V600E与CTNNB1在ACP和PCP中的基因表达差异显著，通过免疫组织化学及分子检测可很好地帮助颅咽管瘤的诊断及鉴别诊断。.
Keywords: Craniopharyngioma; Prognosis; Proto-oncogene proteins B-raf; beta Catenin.