据国外媒体报道，研究人员首次证实一种新的筛选方法有潜力用于鉴定新的人类肿瘤病毒以及确定病毒感染导致了什么类型的癌症。
发现新病原过程中的一个主要的障碍就是鉴定筛选技术的不足。因此，迫切需要可靠的筛选方法。
结膜癌（conjunctival carcinomas）一直都被怀疑是由一种直接的感染源引起的。在这项研究中，研究人员发明了一种叫做数字转录本减法（digital transcript subtraction, DTS）的过程，即一个从数据库减去已知人类序列、剩余非人类序列用于后续研究的系统。
用DTS系统分析241122个结膜癌细胞只发现了21个与之前来自人类数据库的序列不一致的结果——这意味着该系统能够用于筛选人类序列数据库并且鉴定出最有可能的来源于病毒的序列。
研究人员表示，DTS是一个简单的能发现新核苷酸的筛选方法。它首次提供了一些病原类型的定量证据。研究人员将他们的研究成果发表在2007年10月的《病毒学杂志》（Journal of Virology）杂志上。
原始出处:
Journal of Virology, October 2007, p. 11332-11340, Vol. 81, No. 20
Human Transcriptome Subtraction by Using Short Sequence Tags To Search for Tumor Viruses in Conjunctival Carcinoma
Huichen Feng,1 Jennifer L. Taylor,1 Panayiotis V. Benos,2 Robert Newton,3 Keith Waddell,4 Sebastien B. Lucas,5 Yuan Chang,1* and Patrick S. Moore1*
Molecular Virology Program, University of Pittsburgh Cancer Institute,1 Departments of Computational Biology and Human Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania 15213,2 Epidemiology Unit, Radcliffe Infirmary, Cancer Research UK, Gibson Building, Oxford OX2 6HE, United Kingdom,3 Ruharo Eye Hospital, Mbarara,4 Uganda Virus Research Institute, Entebbe, Uganda5
Received 24 April 2007/ Accepted 30 July 2007
Digital transcript subtraction (DTS) was developed to subtract in silico known human sequences from expression library data sets, leaving candidate nonhuman sequences for further analysis. This approach requires precise discrimination between human and nonhuman cDNA sequences. Database comparisons show high likelihood that small viral sequences can be successfully distinguished from human sequences. DTS analysis of 9,026 20-bp tags from an expression library of BCBL-1 cells infected with Kaposi's sarcoma-associated herpesvirus (KSHV) resolved all but three candidate sequences. Two of these sequences belonged to KSHV transcripts, and the third belonged to an unannotated human expression sequence tag. Overall, 0.24% of transcripts from this cell line were of viral origin. DTS analysis of 241,122 expression tags from three squamous cell conjunctival carcinomas revealed that only 21 sequences did not align with sequences from human databases. All 21 candidates amplify human transcripts and have secondary evidence for being of human origin. This analysis shows that it is unlikely that distinguishable viral transcripts are present in conjunctival carcinomas at 20 transcripts per million or higher, which is the equivalent of approximately 4 transcripts per cell. DTS is a simple screening method to discover novel viral nucleic acids. It provides, for the first time, quantitative evidence against some classes of viral etiology when no viral transcripts are found, thereby reducing the uncertainty involved in new pathogen discovery.
* Corresponding author. Mailing address: Hillman Cancer Center, Molecular Virology Program, University of Pittsburgh Cancer Institute, 5117 Centre Ave., Ste. 1.8, Pittsburgh, PA 15213. Phone: (412) 623-7721. Fax: (412) 623-7715. E-mail for Patrick S. Moore: psm9@pitt.edu . E-mail for Yuan Chang: yc70@pitt.edu
