Section of Infectious Diseases, Jefferiss Research Trust Laboratories, Imperial College London, St Mary's Campus, London, W2 1PG, UK.
Retrovirology. 2010 Dec 20;7:108. doi: 10.1186/1742-4690-7-108.
We used a PCR-based approach to study the prevalence of genetic sequences related to a gammaretrovirus, xenotropic murine leukemia virus-related virus, XMRV, in human prostate cancer. This virus has been identified in the US in prostate cancer patients and in those with chronic fatigue syndrome. However, with the exception of two patients in Germany, XMRV has not been identified in prostate cancer tissue in Europe. Most putative associations of new or old human retroviruses with diseases have turned out to be due to contamination. We have looked for XMRV sequences in DNA extracted from formalin-fixed paraffin- embedded prostate tissues. To control for contamination, PCR assays to detect either mouse mitochondrial DNA (mtDNA) or intracisternal A particle (IAP) long terminal repeat DNA were run on all samples, owing to their very high copy number in mouse cells.
In general agreement with the US prevalence, XMRV-like sequences were found in 4.8% of prostate cancers. However, these were also positive, as were 21.5% of XMRV-negative cases, for IAP sequences, and many, but not all were positive for mtDNA sequences.
These results show that contamination with mouse DNA is widespread and detectable by the highly sensitive IAP assay, but not always with less sensitive assays, such as murine mtDNA PCR. This study highlights the ubiquitous presence of mouse DNA in laboratory specimens and offers a means of rigorous validation for future studies of murine retroviruses in human disease.
我们使用基于 PCR 的方法研究与一种γ逆转录病毒、嗜性鼠白血病病毒相关病毒（XMRV）相关的遗传序列在人类前列腺癌中的流行情况。这种病毒在美国已在前列腺癌患者和慢性疲劳综合征患者中被发现。然而，除了德国的两名患者外，XMRV 并未在欧洲的前列腺癌组织中被发现。大多数新的或旧的人类逆转录病毒与疾病的假定关联都被证明是由于污染所致。我们已经在从福尔马林固定石蜡包埋的前列腺组织中提取的 DNA 中寻找 XMRV 序列。为了控制污染，对所有样本进行了检测鼠线粒体 DNA（mtDNA）或内源性 A 颗粒（IAP）长末端重复序列 DNA 的 PCR 检测，这是因为它们在鼠细胞中的拷贝数非常高。
与美国的流行情况大致一致，XMRV 样序列在 4.8%的前列腺癌中被发现。然而，这些样本也对 IAP 序列呈阳性，而 21.5%的 XMRV 阴性病例也呈阳性，许多但并非所有样本对 mtDNA 序列呈阳性。
这些结果表明，鼠 DNA 的污染非常普遍，可通过高度敏感的 IAP 检测方法检测到，但并非总是如此通过敏感性较低的检测方法，如鼠 mtDNA PCR。这项研究突出了实验室标本中普遍存在的鼠 DNA，并为未来研究人类疾病中的鼠逆转录病毒提供了严格验证的方法。
