摘要目的 分析皮肤恶性肢端黑素瘤患者中c-kit基因突变的频率与类型及表达情况.方法 应用PCR、基因测序、免疫组化染色等方法检测115例皮肤恶性黑素瘤(CMM)患者、30例肢端黑素细胞痣患者及15例健康人皮肤组织标本中c-kit基因序列及c-kit蛋白表达情况.采用x2检验、Mann-WhitneyU检验、Spearman相关检验等统计学方法分析数据.结果 93例肢端CMM中84例(90.3％)表达c-kit蛋白,22例非肢端CMM中18例(81.8％)表达.58例肢端侵袭性CMM中,29例真表皮交界处肿瘤细胞c-kit蛋白表达强阳性,而8例真皮内呈侵袭浸润性生长的肿瘤细胞则不表达或弱表达c-kit蛋白;健康人皮肤组织中c-kit蛋白表达较弱;在30例肢端黑素细胞痣中19例(63.3％)阳性表达.c-kit蛋白在93例肢端CMM组的阳性表达率(90.3％)显著高于肢端黑素细胞痣组(63.3％),两组差异有统计学意义(x2=12.14,P＜ 0.05);71例侵袭性CMM中,c-kit蛋白在58例肢端CMM中阳性表达55例(94.8％),在13例非肢端CMM中阳性表达11例,在肢端CMM的表达高于非肢端CMM,两组差异有统计学意义(x2=4.18,P＜ 0.05).在原位、侵袭性、转移性肢端CMM组织中,c-kit蛋白表达水平与肿瘤的临床病理特征均未见明显相关(均P＞0.05).115例CMM中检测到4例患者存在c-kit基因点突变,其中3例为L576P突变,1例为K642E突变,且均为肢端CMM,免疫组化显示弥漫性c-kit蛋白强阳性表达.结论 在侵袭性CMM中,c-kit蛋白在肢端CMM中的表达高于非肢端CMM.肢端CMM中检测到c-kit基因点突变,均为肢端型较常见的突变类型,但突变率较国外文献低.

abstractsObjective To analyze the frequency and type of mutations in the c-kit gene,and to measure the expression of c-kit protein in patients with acral malignant melanoma.Methods Skin tissue specimens were collected from the lesions of 115 patients with cutaneous malignant melanoma (CMM) and 30 patients with acral melanocytic nevi,as well as normal skin of 15 healthy human controls.PCR and DNA sequencing were performed to analyze the sequence of the c-kit gene,and immunohistochemical staining was conducted to observe c-kit protein expression in tissue samples.Statistical analysis was done by Chi-square test,Mann-Whitney U test and Spearman's rank correlation test.Results C-kit protein was expressed in 90.3％ (84/93) of acral CMM specimens,81.8％ (18/22) of non-acral CMM specimens,and 63.3％ (19/30) of acral melanocytic nevus specimens.Among 58 acral invasive CMM specimens,29 showed strong expression of c-kit protein in tumor cells at the dermal-epidermal junction,8 showed negative or weak c kit expression in invasive and infiltrating tumor cells in the dermis.The expression rate of c-kit protein was significantly higher in acral CMM specimens than in acral melanocytic nevus specimens (x2 =12.14,P ＜ 0.05),and higher in acral than in non-acral invasive CMM specimens (94.8％ (55/58) vs.11/13,x2 =4.18,P ＜ 0.05).No significant correlation was observed between the elinicopathological feature of melanoma and expression of c-kit protein in in situ,invasive or metastatic acral CMM tissues (all P ＞ 0.05).C-kit gene mutations were detected in 4 out of the 115 CMM cases,including L576P mutation in 3 cases and K642E mutation in 1 case.All the 4 patients carrying mutations were diagnosed as acral CMM,and exhibited diffuse and strong expression of c-kit protein.Conclusions The expression of c-kit protein is stronger in acral than in non-acral invasive CMM lesions.All the mutations detected in these cases are common typesof c-kit mutations in acral CMM,but the mutation frequency is lower than that reported in foreign literature.