The analysis of p53 tumor suppressor gene in human skin carcinogenesis by p53 yeast functional assay.

本课题旨在通过p53酵母功能测定，分析不同类型皮肤肿瘤中p53抑癌基因的基因突变情况。我们分析了50例皮肤肿瘤，发现10例恶性黑色素瘤中有2例、12例基底细胞癌中有3例、5例鳞状细胞癌中有3例、1例内分泌腺癌中有1例、3例毛囊癌中有3例、5例鲍文氏病中有2例p53突变，1例佩吉特病、1例光化性角化病、1例皮肤纤维瘤和11例痣细胞痣检测阴性。部分阳性病例经DNA测序证实存在基因突变。其中35例进行p53蛋白免疫组化染色，显示基因突变和蛋白过表达。8例p53蛋白过表达的样本中，6例p53酵母功能检测阳性。在27例p53蛋白无过表达的样本中，只有1例呈阳性。综上所述，该技术检测p53基因突变较为简单、灵敏。我们将进一步研究更多的皮肤肿瘤病例，以揭示p53基因在皮肤癌变中的作用。除此之外，我们还研究了PTCH基因在皮肤癌中的作用、端粒酶活性与其亚基表达的相关性、紫外线诱导细胞凋亡的分子机制、氧自由基在紫外线形成DNA损伤中的作用以及日本皮肤癌的流行病学。

The aim of this research project is to analyze the gene mutation of p53 tumor suppressor gene in various types of skin tumors by p53 yeast functional assay. We analyzed 50 cases of skin tumors and found that 2 of 10 malignant melanomas, 3 of 12 basal cell carcinomas, 3 of 5 squamous cell carcinomas, one of one eccrine gland carcinoma, 3 of 3 hair follicle carcinoma and 2 of 5 Bowen's disease had p53 mutation, One Paget's disease, one actinic keratosis, one dermatofibroma and 11 nevus cell nevi were negative for this assay. Some of positive cases with this assay were confirmed for the presence of gene mutation by DNA sequencing. Of these 50 cases, 35 cases were immunohistochemically stained with antibody against p53 protein to reveal the gene mutation and protein overexpression. Of 8 samples with overexpression of p53 protein, 6 were positive for p53 yeast functional assay. Of 27 samples without overexpression of p53 protein, only one was positive for this assay. In summary, this technique was shown to be relatively simple and sensitive for detecting p53 gene mutation. We will examine more cases of skin tumors to reveal the role of p53 gene in skin carcinogenesis by this technique in future. In addition to this research, we also have examined the role of PTCH gene in skin cancer, the correlation of telomerase activity and the expression of its subunits, the molecular mechanism of UV-induced apoptosis, the role of oxygen radical for the formation of DNA damage by UV and the epidemiology of skin cancer in Japan.