组氨酸三聚体核苷结合蛋白1在黑素瘤组织中的表达及其基因启动子甲基化水平研究

目的：检测组氨酸三聚体核苷结合蛋白1（HINT1）在黑素瘤中的表达和HINT1基因启动子甲基化状态，探讨HINT1启动子甲基化与临床病理参数的关系。方法采用甲基化特异性PCR（MSP）法检测56例黑素瘤及瘤旁组织和51例色素痣组织中HINT1基因启动子区甲基化水平，免疫组化法检测56例黑素瘤和51例色素痣组织中HINT1蛋白的表达。结果 MSP显示，黑素瘤组织、瘤旁组织及色素痣组织中HINT1基因启动子区甲基化率分别为76.8%（43/56）、33.9%（19/56）和35.3%（18/51），黑素瘤组HINT1基因启动子区甲基化率明显高于瘤旁组织组和色素痣组，且差异有统计学意义（χ2=20.810、18.749，均P<0.05），瘤旁组织组与色素痣组间差异无统计学意义（χ2=0.022，P>0.05）。免疫组化显示，56例黑素瘤和51例色素痣组织中分别有12例（21.4%）和42例（82.4%）HINT1蛋白阳性表达，两组阳性率差异有统计学意义（χ2=39.633，P<0.01）。12例HINT1蛋白阳性的黑素瘤组织中，有6例HINT1基因启动子甲基化，而在44例HINT1蛋白阴性的癌组织中HINT1启动子甲基化率高达84.1%（37/44），两组差异有统计学意义（χ2=6.147，P=0.013）。56例黑素瘤中，HINT1基因启动子区甲基化率在Clark分级Ⅰ~Ⅱ级组（59.1%，13/22）与Ⅲ~Ⅴ级组（88.2%，30/34）间差异有统计学意义（χ2=6.365，P=0.012）。结论 HINT1在黑素瘤组织中低表达，其机制可能与启动子区发生高甲基化有关；HINT1启动子区高甲基化可能参与黑素瘤的发生及发展。

HINT1 protein expression and gene promoter methylation in melanoma tissue

Objective To measure histidine triad nucleotide?binding protein 1(HINT1)protein expression and gene promoter methylation, and to analyze the relationship between HINT1 gene promoter methylation and clinical pathological features of melanoma. Methods Fifty?six patients with melanoma and 51 patients with nevus were enrolled as subjects and controls, respectively. Methylation?specific PCR (MSP) was performed to measure the methylation of HINT1 gene promoter in lesional and paratumoral tissue specimens from the patients with melanoma, as well as in lesional specimens from the patients with nevus. Immunohistochemistry was carried out to quantify the expression of HINT1 protein in these tissue specimens. Results MSP showed that the methylation rate of HINT1 gene promoter was significantly higher in melanoma tissues than in paratumoral and nevus tissues(76.8%43/56]vs. 33.9%19/56]and 35.3%18/51], χ2 = 20.810 and 18.749, respectively, both P < 0.05), but was insignificantly different between paratumoral and nevus tissues(χ2=0.022, P>0.05). Immunohistochemistry revealed that the expression rate of HINT1 was 21.4%(12/56)in melanoma tissues, compared to 82.4%(42/51)in nevus tissues(χ2 = 39.633, P <0.01). There was a significant difference in the methylation rate of HINT1 promoter between HINT1?positive and ?negative melanoma tissues(6/12 vs. 37/4484.1%], P<0.05), and between Clark levelⅠ-ⅡandⅢ-Ⅴmelanoma tissues(59.1%13/22]vs. 88.2%30/34],χ2=6.365,P=0.012). Conclusions HINT1 protein is lowly expressed in melanoma, which may be associated with high methylation of its gene promoter. Moreover, the high methylation ofHINT1 gene promoter may be involved in the initiation and progression of melanoma.