A map of the viral integration sites of Human Papilloma Virus (HPV), the leading cause of cervical cancer, is reported in a paper published online this week in Nature Genetics. Viral integration, the process by which the virus inserts its DNA into the host’s DNA, is one of the major risk factors for developing cervical cancer following HPV infection.

Ding Ma and colleagues used a method called high-throughput viral integration detection to find 3,667 HPV integration sites in over 100 cervical cancer samples. They identified nine genes that had integration sites in at least five samples, and 33 genes with integration sites in at least four samples. Viral integration led to either loss or gain of host gene expression, both of which can increase the risk of developing cancer, depending on where the virus integrated into the gene. These findings may help researchers understand the early stages of cervical cancer development and may improve cervical cancer screening in the clinic.