本文采用右胸腔内注入染尘法，对大鼠染青石棉尘４０ｍｇ。收集１９例胸膜间皮瘤标本，提取标本中ＤＮＡ，用人工合成的寡核苷酸引物行ＰＣＲ体外扩增，再用ｒ－（３２）ＰＡＴＰ标记正常和两种空变Ｋｉ－ｒａｓ１２位探针，杂交，放射自显影。结果表明，７例正常对照组标本Ｋｉ－ｒａｓ１２位点突变为阴性；１９例间皮瘤标本中，２例突变阳性，其中１例由ＧＧＴ（Ｇｌｙ）突变为ＡＧＴ（Ｓｅｒ），１例由ＧＧＴ（Ｇｌｙ）突变为ＴＧＴ（Ｃｙｓ）。 In this paper, right chest injection of dust method, the rat crocidolite dust 40mg. Nineteen cases of pleural mesothelioma were collected and the DNA of the samples was extracted. PCR was performed in vitro by using synthetic oligonucleotide primers, then r- (32) PATP was used to label normal and two empty ki-ras 12-position probes , Hybridization, autoradiography. The results showed that Ki-ras12 locus mutation was negative in 7 normal control specimens. Of the 19 mesothelioma specimens, 2 were positive for mutation, of which 1 was GGT (Gly) to AGT (Ser) and 1 was GGT (Gly) to TGT (Cys).