【作者】 尹利华；

【导师】 孟秀香；

【作者基本信息】 大连医科大学 ， 生物化学与分子生物学， 2009， 硕士

【摘要】 目的:黑色素瘤(Malignant melanoma,MM)是来源于黑色素细胞的一种高度恶性肿瘤,其发病机理及病因仍不明确,至今也尚无有效的治疗手段。目前的研究发现多种癌基因介入黑色素瘤的发病机制中。多梳基因(polycomb group genes, PcG)家族的Bmi-1(B-cell-specific moloney leukemia virus insert site1)被认为是一种癌基因,在多种肿瘤组织中均有表达增高,但其在黑色素瘤中的表达及其意义尚存在争议。为了进一步求证Bmi-1在黑色素瘤中的作用,本实验选取临床确诊的35例黑色素瘤及14例色素痣为对照,免疫组化法检测Bmi-1蛋白的表达,并与细胞增殖抗原Ki-67进行相关比较,以明确黑色素瘤中Bmi-1与肿瘤恶性程度的关系。此外,我们还检测了Bmi-1下游信号传导通路中的一个关键靶蛋白P16,初步探讨了Bmi-1作用的分子机制。方法:⑴收集湖南省肿瘤医院2003年~2007年黑色素瘤患者经手术切除后获得的石蜡标本35例为研究对象,并选择14例色素痣标本作为良性对照;⑵所有标本由两位临床病理医师确认,并经S—100蛋白、HMB45蛋白免疫组化染色确诊;⑶SP免疫组化法分别检测35例黑色素瘤和14例色素痣组织石蜡切片中Bmi-1、Ki-67、P16的表达;⑷半定量分析Bmi-1、Ki-67、P16的表达情况,并对Bmi-1与Ki-67/P16行相关性统计分析。结果:⑴黑色素瘤组中Bmi-1阳性表达率与色素痣组相似(63% vs 71%,P >0.05);但中高阳性表达率却明显高于色素痣组(51% vs 14%, P < 0.05),且该表达与患者性别、年龄、肿瘤体积大小、发病部位、淋巴结转移等因素均无关,但与病理分级(Clark标准)关系密切,即Ⅲ、Ⅳ级黑色素瘤Bmi-1的阳性表达率明显高于Ⅰ、Ⅱ级黑色素瘤(67% vs 29%,P <0.05)。⑵黑色素瘤组患者Ki-67的阳性表达率及中高阳性表达率均较色素痣组明显增强(阳性率:77% vs 21%, P <0.01;中高阳性率:54% vs 0%, P <0.01),且相关性分析表明Bmi-1与Ki-67呈正相关(P <0.01)。⑶P16免疫组化染色发现黑色素瘤组P16阳性表达率及中高阳性表达率较色素痣组明显降低(阳性率:17% vs 93%,P <0.01;中高阳性率:6% vs 71%,P <0.01)。结论:⑴黑色素瘤组中Bmi-1的高表达,提示Bmi-1基因很可能介入了黑色素瘤的发病过程;⑵黑色素瘤组中Ki-67与Bmi-1呈正相关,提示Bmi-1与黑色素瘤的恶性程度关系密切,进一步支持Bmi-1介入了黑色素瘤的发病过程;⑶黑色素瘤组P16表达的降低,提示黑色素瘤的发生可能与P16表达下降有关,但Bmi-1与P16相关性分析显示二者并不存在相关性,这说明Bmi-1的作用很可能不是通过P16通路介导的,可能存在其它机制。更多还原

【Abstract】 Background: Melanoma is a highly malignant tumor which derives from melanocytes in the skin. The underlying mechanism responsible for melanoma still remains unclear and no effective strategy to halt the pro- gression of melanoma. Many oncogenes have been reported to be involved in the pathogenesis of melanoma. Bmi-1,a member of polycomb group fami- ly, has been found over-expressed in a few type of tumors. However, the significance of Bmi-1 in melanoma is still unknown. To investigate the role of Bmi-1 in melanoma, tumor samples were collected from 35 melanoma patients and 14 melanotic nevus patients. The expression of Bmi-1, Ki-67 or P16 was detected with immunohistochemistry. To determine the relationship between Bmi-1 and malignancy of melanoma, the correlation analysis be- tween Bmi-1 and Ki-67 was studied, since Ki-67 is generally used for la- belling the proliferation state of tumor cells. In addition, to explore the mechanism of Bmi-1 in melanoma, P16, as a downstream target protein of Bmi-1, was also detected.Methods:⑴Tumor samples were collected from 35 melanoma patients and 14 melanotic nevus patients between 2003-2007 in HuNan Tumor Hosp- ital;⑵All the samples were diagnosed as melanoma by two pathologists with S-100 and HMB45 immunohistochemistry;⑶The expression of Bmi-1, Ki-67 or P16 was detected with immunohistochemistry;⑷The half-quanti- fication analysis of Bmi-1/Ki-67/P16 and the correlation between Bmi-1 and Ki-67/P16 were studied. Results:⑴Although there was no difference in Bmi-1 positive percentage between melanoma group and melanotic nevus group(63% vs 71%, P>0.05),Bmi-1 high positive percentage in melanoma group was high- er than that in melanotic nevus group(51% vs 14%, P<0.05). Except pathological stage (Clark standard), there was no correlation between Bmi-1 and age, sex, tumor location, tumor size, and lymph node metastasis. For the pathological stage, the Bmi-1 positive percentage in stageⅢorⅣwas significantly higher than that in stageⅠorⅡ(67% vs 29%,P<0.05).⑵Both Ki-67 positive percentage and Ki-67 high positive percentage were higher in melanoma group than those in melanotic nevus group(positive percent- tage:77% vs 21%, P<0.01; high positive percentage: 54% vs 0%, P<0.01). In addition, Bmi-1 expression was significantly correlated with Ki-67 expression(P<0.01).⑶Both P16 positive percentage and P16 high positive percentage were lower in melanoma group than those in melanotic nevus group(positive percentage:17% vs 93%, P<0.01;high positive percentage: 6% vs 71%, P<0.01). However,there was no correlation between Bmi-1 and.P16.Conclusions:⑴The increased Bmi-1 expression in melanoma indicates that Bmi-1 might be involved in the pathogenesis of melanoma;⑵The significant positive correlation between Bmi-1 and Ki-67 expression indicates that Bmi-1 might be related with malignancy of melanoma and this further supports above conclusion;⑶The decreased P16 expression indicates that P16 might be associated with the progression of melanoma. No correlation between P16 and Bmi-1 suggests that the effect of Bmi-1 in melanoma is not mediated by P16. There might be some unknown mechanism in it.更多还原