Several viruses are known to cause cancer, such as human herpes virus 8 in Kaposi sarcoma and human papilloma viruses in cervical cancer. Recently, Merkel cell polyoma virus (MCPyV) has been described in 80% of Merkel cell carcinomas (MCC). Similarly to MCC and Kaposi sarcoma, melanoma incidence is increased in immunosuppressed patients.
Melanoma is an aggressive type of cancer; known risk factors to develop melanoma are UV exposition, age and skin type. Intriguingly, melanoma also occurs more frequently in immunosuppressed patients. Although electron microscopy revealed virus-like particles in melanoma, up to now, no virus causing melanoma could be identified. Researchers at University of Tübingen, Germany set out to determine whether infection by known or yet unknown viruses may play a role in melanoma development as well.
To detect viral sequences expressed in melanoma cells, they analysed three melanoma metastases by whole-transcriptome sequencing and digital transcriptome subtraction. None of the samples investigated harboured viral sequences. In contrast, artificial viral sequences and MCPyV transcripts used as a positive control for the bioinformatics analysis were detected. This renders it less likely that viruses are frequently involved in melanoma induction. A larger number of melanoma transcriptome sequencings are required to rule out viruses as a relevant pathogen.
Feldhahn M, Menzel M, Weide B, Bauer P, Meckbach D, Garbe C, Kohlbacher O, Bauer J. (2011) No evidence of viral genomes in whole-transcriptome sequencing of three melanoma metastases. Exp Dermatol [Epub ahead of print]. [abstract]