RESPIRATORY CARCINOGENESIS BY CHEMICAL AND PHYSICAL FACTORS

用肺组织研究分子标记和基因改变 从用二氧化硅（12 mg Min-U-Sil 5石英）处理的F344大鼠，通过单次 阴道内滴注。 这是一个独特的动物模型， 纤维化相关周围型肺癌的发病机制。 它 周围型肺癌的发病率很高， 肺泡II型上皮细胞，邻近矽肺肉芽肿， 马斯 完成了TGF-β 1分布的研究（观察大鼠 6个月或更长时间），在矽肺肉芽肿和相邻肺泡 II型增生、腺瘤和癌，使用免疫组织化学。 合成肽的多克隆抗体，对应于成熟的 和前体TGF-β 1，定位如下：TGF-β 1前体 在邻近硅肺肉芽肿的增生的II型细胞中， 腺瘤样增生和腺瘤，但不是癌;成熟 TGF-β 1定位于成纤维细胞和巨噬细胞的细胞内， 邻近II型增生的矽肺肉芽肿周围 细胞，以及邻近结缔组织基质的细胞外 增生的II型细胞。 这些发现表明了致病作用 对于肺泡II型细胞产生的TGF-β 1， 以及相关的致癌作用。 泛反应性ras数量增加 p21蛋白定位于增生的肺泡Ⅱ型细胞，而不表达于肺泡上皮细胞。 在腺瘤和癌中。 p53的免疫组织化学定位 蛋白质，使用多克隆抗血清（CM-1）显示核反应性， 25%的癌，而正常、增生或腺瘤中无 II型细胞建立了一种RNA提取方法， 使用石蜡包埋的大鼠肺组织进行分析， 癌 聚合酶链反应对来自提取的RNA的cDNA， 以及从显微切割的癌中提取的DNA， 随后进行单链构象多态性（SSCP）分析， 直接DNA测序，到目前为止，没有显示在外显子1的点突变， ras基因和大鼠p53基因的外显子4-8。

Molecular markers and gene alterations were studied, using lung tissues from F344 rats treated with silica (12 mg Min-U-Sil 5 quartz), by single intratracheal instillation. This is a unique animal model for studying the pathogenesis of fibrosis-associated peripheral lung carcinomas. It yields a high incidence of peripheral lung carcinomas, derived from hyper- plastic alveolar type II epithelial cells, adjacent to silicotic granulo- mas. A study of TGF-beta1 distribution was completed (for rats observed for 6 months or longer), in silicotic granulomas and in adjacent alveolar type II hyperplasias, adenomas and carcinomas, using immunohistochemistry. Polyclonal antibodies to synthetic peptides, corresponding to the mature and precursor TGF-beta1, were localized as follows: TGF-beta1 precursor in the hyperplastic type II cells adjacent to silicotic granulomas, adenomatoid proliferations and adenomas, but not in carcinomas; mature TGF-beta1 was localized intracellularly in fibroblasts and macrophages at the periphery of silicotic granulomas adjacent to hyperplastic type II cells, and extracellularly in the connective tissue matrix adjacent to hyperplastic type II cells. These findings suggest a pathogenetic role for TGF-beta1 produced in the alveolar type II cells, both in silicosis and in associated carcinogenesis. Increased amounts of pan-reactive ras p21 protein were localized in hyperplastic alveolar type II cells, but not in adenomas and carcinomas. Immunohistochemical localization of p53 protein, using polyclonal antisera (CM-1) revealed nuclear reactivity in 25% of the carcinomas, but none in normal, hyperplastic or adenomatous type II cells. An RNA extraction method was developed for molecular analyses using paraffin embedded rat lung tissues with silica-associated carcinomas. Polymerase chain reaction on cDNA derived from extracted RNA, and also on extracted DNA, obtained from microdissected carcinomas, followed by single strand conformational polymorphism (SSCP) analysis and direct DNA sequencing, have so far showed no point mutations in exon 1 of the ras gene and exons 4-8 of the rat p53 gene.