Preferential integration of human papillomavirus type 18 near the c-myc locus in cervical carcinoma

The development of cervical cancer is highly associated with human papillomavirus (HPV) infection. Greater than 99% of all cervical tumors contain HPV DNA. Integration of high-risk HPV has been temporally associated with the acquisition of a malignant phenotype. Recent work from our lab has shown that HPV16, the most common high-risk HPV associated with cervical carcinoma, preferentially integrates at loci containing human common fragile sites (CFSs). CFSs are regions of genomic instability that have also been associated with deletions, translocations, and gene amplification during cancer development. The current work shows that HPV18, the second most prevalent high-risk HPV type found in cervical tumors, preferentially targets the CFSs. We identified 27 unique HPV18 integrations in cervical tumors, of which 63% (P<0.001) occur in CFSs. However, the distribution of HPV18 integrations found were profoundly different from those found for HPV16. Specifically, 30% of all HPV18 integrations occurred within the chromosomal band 8q24 near the c-myc proto-oncogene. None of the HPV16 integrations occurred in this region. Previous low-resolution mapping suggested that c-myc may be a target of HPV integration. Our data at nucleotide resolution confirm that in HPV18-positive cervical tumors, the region surrounding c-myc is indeed a hot spot of viral integration. These results demonstrate that CFSs are preferred sites of integration for HPV18 in cervical tumors. In addition, we have identified multiple cellular genes that have been disrupted by HPV18 integration in cervical tumors. Our results suggest that the sites of HPV18 integration are nonrandom and may play an important role in the development of cervical tumors.