MOLECULAR GENETICS OF UROLOGICAL TUMOURS

我们对24例肾细胞癌（RCC）、18例前列腺癌（PC）和11例肾盂移行细胞癌（TCC）进行限制性内切片段长度多态性（RFLP）分析，研究肿瘤抑制基因的扩增和失活情况。所有病例均未见Harvey ras、c-myc、c-fos、EGFR和PDGFR的扩增和重排。相反，RFLP分析表明，在所研究的肿瘤形式中，等位基因丢失被解释为tsg的失活事件。RCC在3号染色体短臂（3p）（68%）、18号染色体长臂（18q）（33%）、Y染色体（29%）和17p染色体（27%）上的等位基因丢失频率较高。PC在16q（67%）、8p（50%）、18q（43%）、10p（40%）和10q（38%）上显示频繁的等位基因丢失。TCC在17p（73%）、11p（64%）和9q（40%）上有等位基因缺失。肿瘤恶性程度越高的患者可能有越多的等位基因丢失。采用逆转录聚合酶链式反应（RT-PCR）技术检测前列腺特异性抗原（PSA） mRNA，以鉴定前列腺癌细胞。一组来自不同人类肿瘤的细胞系进行了研究，结果除了前列腺癌细胞系LNCaP细胞外，没有细胞系检测呈阳性。通过将psa阳性LNCaP细胞与psa阴性的人胚胎肺成纤维细胞（HEL）连续稀释，测试了该方法的灵敏度。紫外照射下琼脂糖凝胶上仅检测到HEL细胞1 mg RNA中LNCaP细胞的10^<-4> mg RNA。因此，psa定向RT-PCR检测可作为前列腺癌细胞的敏感特异性分子标志物。在前列腺癌患者的不同阶段，这种检测的阳性结果如下：A1 1期0分；A2 2期0分；5期2分；B期2分；8期2分；C期3分；D0 4期1分；D1 11期7分。36例前列腺癌患者中16例（44.4%）阳性。基于psa的RT-PCR检测在个体前列腺癌早期分期诊断方面的临床有效性正在评估中。p53基因是一种常见的肿瘤抑制基因，与多种人类恶性肿瘤的发生有关。我们研究了18例未经临床治疗的前列腺癌中p53基因的突变事件。直接测序分析表明，18例病例中有1例在高度保守的转录区存在点突变。该病例在密码子273处显示CAT，而不是野生型CGT，将编码的氨基酸从组氨酸替换为精氨酸。该病例先前通过限制性片段长度多态性分析发现17p上存在纯合位点，包括p53位点。另外17例没有突变或小缺失。由此可见，p53基因的点突变在未经治疗的前列腺癌的发生中是一个罕见的事件。少

We applied restriction fragment length polymorphism (RFLP) analysis to 24 cases of renal cell carcinomas (RCC) , 18 cases of prostate adenocarcinoma (PC) , and 11 cases of transitional cell carcinomas (TCC) in renal pelvis to study the oncogene amplification and inactivation of tumor suppresor genes. All of the cases showed no amplification nor gross rearrangements of the Harvey ras, c-myc, c-fos, EGFR and PDGFR.In contrast, RFLP analyzes demonstrated allelic losses interpreted as inactivational events of TSGs among the tumor forms studied. RCC had allelic losses on the short arm of chromosome 3 (3p) (68%) , the long arm of chromosome 18 (18q) (33%) , Y chromosome (29%) , and 17p (27%) at high frequencies. PC showed frequent allelic losses on 16q (67%) , 8p (50%) , 18q (43%) , 10p (40%) , and 10q (38%) . TCC had allelic losses on 17p (73%) , 11p (64%) , and 9q (40%) . It was likely that the cases with the more malignant grade tumor had the more allelic losses.We tried to identify prost … More ate cancer cells by detecting messenger RNA (mRNA) of prostate specific antigen (PSA) amplified using reverse transcriptase-polymerase chain reaction (RT-PCR) assay. A panel of cell lines derived from diverse human neoplastic tumors were investigated, resulting that no cell lines tested were positive by the assay except for prostate cancer cell line, LNCaP cells. Sensitivity of the assay was tested using a serial dilution of PSA-positive LNCaP cells with PSA-negative human embryonic lung fibroblast (HEL) cells. Only 10^<-4> mg RNA of LNCaP cells in 1 mg RNA of HEL cells was detected on the a agarose gel under ultraviolet illumination. Therefore, the PSA-directed RT-PCR assay could be sensitive and specific molecular marker for prostate cancer cells.The positivities of this assay in a spectrum of stages of prostate cancer patients were as follows ; 0 of 1 stage A1 : 0 of 2 stage A2 : 2 of 5 stage B : 2 of 8 stage C : 3 of 3 stage D0 : 1 of 4 stage D1 : 7 of 11 stage D2.totally, 16 of 36 patients with prostate cancer (44.4%) were positive. The clinical usefulness of the PSA-based RT-PCR assay is under assessment in terms of earlier staging diagnosis of prostate cancer in an individual case.The p53 gene is known to be one of the frequently altered tumor suppressor genes, and involved in the oncogenesis of a wide spectrum of human malignant tumors. We investigated mutational event of the p53 gene in 18 clinically untreated prostate cancers. Direct sequencing analysis demonstrated that 1 of 18 cases harbored point mutation in the highly conserved transcript region. The case showed CAT at codon 273 instead of wild type CGT,substituting the encoded amino acid from histidine to arginine. The case had previously revealed homozygous loci on 17p, including the p53 locus, by restriction fragment length polymorphism analysis. Other 17 cases harbored no mutation nor small deletion. It is concluded that point mutation of the p53 gene is a infrequent event in the oncogenesis of untreated prostate cancer. Less