Fig. (5) Venn diagrams illustrating the overlap in differentially expressed genes reported in: A) studies based on cervical cancer tissues. The signatures reported by Rosty et al. [46] and Santin et al. [45, 47] show significant overlap. This is in contrast to the list of genes published by Carlson et al. [38] that shows only negligible overlap with the other studies. The genes present in all three studies are RFC2, TOP2A, PTTG1, UBE2C (upregulated) and SERPINF1 (downregulated) (also seen in Fig. 3). B) Studies of low-risk HPV. Santegoets et al. [51] and DeVoti et al. [52] reported the differentially expressed genes from condyloma and papilloma samples, respectively. Thomas et al. [37] reported the differential expression based on a cell culture model in which normal human keratinocytes were transfected with the HPV11 genome. The Venn diagram demonstrates a notable overlap between the tissue-based studies, especially concerning downregulated genes. However, little overlap can be seen between the tissue-based studies and the HPV11 cell culture model (Thomas_HPV11). C) Studies reporting the differential expression between HPV-positive versus HPV-negative head-and-neck cancers. These studies show very little overlap of the signatures. The two genes upregulated in all the studies are SYCP2 and CDKN2C (also seen in Fig. 4).