In addition, our previous reports found that cyclin D1, c-Myc and hTERT protein expression levels in HPV16/18 E6-positive lung tumors were significantly higher than in HPV16/18 E6-negative tumors [42,43], suggesting that HPV16/18 infection can activate the expression of oncogenes, such as c-myc, cyclinD1and hTERT. This evidence concerns the gene CCND1 and infection.