皮肤黑素瘤94例临床病理特点与基因突变的关系

Association between clinicopathological characteristics and gene mutations in 94 cases of cutaneous melanoma

目的探讨皮肤黑素瘤(CMM)临床病理特点及与易感基因突变的关系。方法回顾分析新疆维吾尔自治区人民医院2009年1月至2019年12月确诊的94例CMM临床及组织病理学特征。48例留存黑素瘤石蜡组织标本,采用Sanger测序法检测黑素瘤组织中BRAF、NRAS、c-KIT基因及人端粒酶逆转录酶(hTERT)基因启动子区突变情况;分析基因突变与临床病理特征的关系。计量资料的比较采用t检验,计数资料采用卡方检验或Fisher精确检验法。结果94例CMM中,男46例(48.9%),女48例(51.1%),年龄(58.5±16.0)岁。汉族41例(43.6%),少数民族53例(56.4%)。发病部位为肢端50例(53.2%),其中27例(65.8%)为汉族;非肢端患者44例(46.8%),14例(31.8%)为汉族,两组民族分布差异有统计学意义(χ^(2)=5.25,P=0.022)。组织病理特征:41例(43.6%)Clark分级处于Ⅳ、Ⅴ级,52例(55.3%)可见溃疡,32例(34.04%)初诊即有淋巴结转移。48例中,11例(22.9%)出现BRAF基因突变,包括c.1799 T>A(p.V600E)、c.1790 T>A(p.L597Q)、c.1394 C>T(p.S465F);5例(10.4%)出现NRAS基因c.182 A>G(p.Q61R)突变;6例(12.5%)出现c-KIT基因突变,包括c.1727 T>C(p.L576P)、c.1669 T>C(p.W557R);7例(14.6%)出现hTERT基因启动子区突变,4例为距起始密码子ATG上游124 bp(C228T),3例为146 bp(C250T)。26例<60岁患者中,发生BRAF突变9例,显著高于60岁以上患者(22例中2例发生突变,P<0.05),肢端型患者发生率(3/27例)低于非肢端型(8/21例,P<0.05);有淋巴结转移的患者中NRAS、c-KIT、hTERT突变发生率(3/10、4/10、4/10例)均高于无淋巴结转移的患者(2/38、2/38、3/38例,均P<0.05)。结论不同民族CMM的发病部位有差异;BRAF基因突变与CMM患者年龄、发病部位相关;NRAS、c-KIT基因突变、hTERT基因启动子区突变与是否有淋巴结转移相关。

Objective To investigate associations between clinicopathological characteristics and mutations in susceptibility genes in cutaneous melanoma(CMM).Methods A total of 94 patients with confirmed CMM were collected from People′s Hospital of Xinjiang Uygur Autonomous Region from January to December in 2019,and their clinical and histopathological characteristics were retrospectively analyzed.In 48 paraffin-embedded melanoma tissue specimens,Sanger sequencing was performed to detect mutations in the BRAF,NRAS,c-KIT genes and the promoter region of human telomerase reverse transcriptase(hTERT)gene,and the association between gene mutations and clinicopathological characteristics was analyzed.Measurement data were compared using t test,and enumeration data were compared using chi-square test or Fisher′s exact test.Results Among the 94 patients with CMM,there were 46(48.9%)males and 48(51.1%)females,with the age being 58.5±16.0 years;41(43.6%)patients were of Han nationality,and 53(56.4%)were of ethnic minorities.Skin lesions were located at the acral sites in 50(53.2%)patients,including 27(28.7%)of Han nationality;non-acral skin lesions occurred in 44(46.8%),including 14(31.8%)of Han nationality;there was a significant difference in the nationality distribution between the acral CMM group and non-acral CMM group(χ^(2)=5.25,P=0.022).Histopathological examination showed CMM of Clark gradesⅣorⅤin 41(43.6%)cases,ulcers in 52(55.3%)cases,and lymph node metastasis in 32(34.04%)cases at the first clinic visit.Gene sequencing revealed BRAF gene mutations in 11(22.9%)of 48 cases,including c.1799 T>A(p.V600E),c.1790 T>A(p.L597Q)and c.1394 C>T(p.S465F);NRAS gene mutation c.182 A>G(p.Q61R)was identified in 5(10.4%)cases;c-KIT gene mutations were identified in 6(12.5%)cases,including c.1727 T>C(p.L576P)and c.1669 T>C(p.W557R);mutations in the promoter region of hTERT gene were identified in 7(14.6%)cases,including 4 cases with a mutation at 124 bp upstream of the ATG start codon(C228T)and 3 cases with a mutation at 146 bp upstream of the ATG start codon(C250T).Among 26 patients aged<60 years,BRAF gene mutations were found in 9,and the incidence of BRAF gene mutations was significantly higher in the patients aged<60 years than in those aged≥60 years(2/22,P<0.05),but significantly lower in the patients with acral CMM(3/27)than in those with non-acral CMM(8/21,P<0.05);the incidences of the NRAS,c-KIT and hTERT gene mutations were all significantly higher in the patients with lymph node metastases(3/10,4/10,4/10,respectively)than in those without(2/38,2/38,3/38,respectively,all P<0.05).Conclusion CMM lesion locations significantly differed among different ethnic groups;the BRAF gene mutation was associated with the age of patients and lesion locations of CMM;NRAS,c-KIT gene mutations and hTERT promoter mutations were closely related to lymph node metastasis.