The viral skinny
H. Feng, et al., “Clonal integration of a polyomavirus in human Merkel cell carcinoma,” Science, 319:1096–100, 2008. (Cited 163 times)
When the husband and wife team of Yuan Chang and Patrick Moore started looking for the causes of Merkel cell carcinoma (MCC), a rare skin cancer, they suspected a virus. They had discovered that Kaposi’s sarcoma was caused by a herpesvirus 16 years ago, and both Kaposi’s and MCC occur more often in immunosuppressed patients. Once again, they found a new type of polyomavirus present in 8 of 10 MCC samples tested.
Yang and Moore spent 10 years developing a technique known as digital transcriptome subtraction, which they used to detect the virus. They sequenced the complete cDNAs of four MCC tumors and isolated sequences that didn’t align with the human genome, says Moore. They then compared those 2,400 isolated sequences against virus genomes, finding a sequence that matched a known virus—specifically, a polyomavirus, but one that had never been described before.
While investigators have since found the virus in many other MCCs around the world, it’s not yet clear whether the virus plays a role in the cancer. “The causality question hasn’t been nailed down,” says Rafael Viscidi, from Johns Hopkins Bloomberg School of Public Health.
The follow up:
Polyomavirus typically causes cancers in animals; Chang and Moore and others are investigating whether the virus’s T-antigen, the oncogene thought to cause MCC in animals, is involved in MCC tumor progression.
|Cells types with new polyomavirus:|
|MCC cancer cell samples:||80%|
|Skin cells with non-MCC cancer:||16%|