Adjunctive immunohistochemistry tests for human papillomavirus (HPV)
infection include p16 and Ki67 as well as the more recently discovered
biomarkers importin-β, exportin-5, Mcl1, and PDL1. The purpose of this study was to compare the expression of these
biomarkers in
HPV infection due to the high-risk types such as HPVs 16, 18, 31, 33, 35, and 51 versus lesions that contain the low risk types HPV 2, 6 or 11. We studied 35 lesions with low risk HPV types (
verruca vulgaris = 10 cases, condyloma acuminatum = 15 cases, CIN 1 with HPV 6/11 = 10 cases) and 25 CIN 1 or 2 lesions with a high-risk HPV type. The 25 high-risk positive CIN 1-2 cases had strong expression of the panel p16, Ki67,
importin-β, exportin-5, Mcl1, and PDL1 where each
protein localized to the cells in the parabasal aspect of the lesion. In comparison, neither p16,
importin-β, exportin-5, Mcl1, nor PDL1 were increased in the epithelia of the lesions with the low risk HPV types; Ki67 showed variable expression. HPV viral capsid L1
protein and
viral DNA were excellent markers of
infection in the lesions with low risk types. Thus, p16,
importin-β, exportin-5, Mcl1, and PDL1 are not only
biomarkers of high-risk
HPV infection but can also differentiate such lesions from those that contain low risk HPV types. Low risk
HPV infections can be best differentiated from their mimics by viral L1 capsid detection and/or HPV
DNA by in situ hybridization.