Comparison of HPV genotypes and viral load between different sites of genital tract: The significance for cervical cancer screening

ObjectivesTo compare the consistency of HPV genotype and viral loads among different sites within the female genital tract, and to correlate these with clinical outcomes.Methods2646 previously unscreened rural women were enrolled in this population-based, cross-sectional study between May 2006 and April 2007. Physician-collected samples from lower vagina, upper vagina, cervix, and one self-collected sample were taken from each woman. Viral load was assessed by HC2 using the relative light unit/cutoff ratio (RLU/CO), and HPV genotyping was tested by Linear Array.ResultsThe low risk HPV positive rate was highest in lower vagina samples and lowest in cervix samples. Overall kappa values of high risk HPV types between various anatomic sampling sites showed substantial or almost perfect agreement among women with normal pathology, CIN1, and CIN2+. In the CIN2+ population, high risk HPV viral load for cervix samples (557.25 RLU/CO) were much higher than upper vagina samples (96.43 RLU/CO, P < 0.001), lower vagina samples (36.51 RLU/CO, P < 0.001), and self-collected (206.83 RLU/CO, P = 0.003) samples.ConclusionsAlthough the distribution of high risk HPV genotypes was fairly equivalent across different genital sites, particularly for CIN2+ lesions, viral loads were largely variable. The findings may affect the cervical cancer screening methods using self-collected samples, particularly in resource-challenged areas.