Background: The natural history and carcinogenicity of rare and novel HPV types is unclear.
Materials and methods: From a total of 5,964 women tested for HPV by PCR and sequence analysis, Pap smears from 293 patients harbouring mono-infection with low-risk, undetermined-risk or novel HPV genotypes were investigated.
Results: Sixty-three percent of patients had ASC-US, 23% LSIL, 9% were negative and 5% had HSIL in cytology. Of 30 HPV types detected, 19 were of unknown risk (UR)-types including 3 novel genotypes. Four of the UR-HPVs (HPV 69, 30, 67 and 34) could be assigned as probable high-risk types and eight as low-risk types based on phylogenetical relationship. Morphology was not discriminative with regard to HPV type, but non-classical HPV-signs were generally present even in "normal" cytologies.
Conclusion: HPV-typing is important for risk-adapted individual patient management. Women harbouring novel high-risk or probably high-risk HPVs require more intensive care than those bearing non high-risk infections.