Zombies in TCGA.

Next-generation sequencing results obtained to detect somatic mutations in human cancers can also be searched for viruses that contribute to cancer. Recently, human papillomavirus 18 RNA was detected in tumor types not typically associated with HPV infection. Analyses reported in this issue of Journal of Virology demonstrate that the apparent presence of HPV18 RNA in these atypical tumors is due in at least some cases to contamination of samples with HeLa cells, which harbor HPV18.