Multiple HPV 16 infection with two strains: a possible marker of neoplastic progression.

BACKGROUND

We studied the cases of single and multiple HPV infection and analyzed the correlation with negative cases, and preneoplastic and neoplastic lesions of the uterine cervix with the aim of making a contribution to the prognostic factor under discussion.

METHODS

Nine hundred nine women undergoing second level screening because they had been positive at cervical cytology were enrolled. All the patients underwent colposcopy and cervical biopsy with viral genotyping. We divided mHPV infection based on the number of genotypes present: infections with 2 strains, 3 strains, 4 strains and 5 or more strains.

STATISTICAL ANALYSIS

The analysis of the data was made using the χ2 test. Contingency tables were created to evaluate the correlation between single, multiple and CIN2+ infections. Values with p < 0.05 were considered statistically significant.

RESULTS

The presence of genotype HPV16 in our study was associated with a 12 times greater risk of developing a high-grade lesion, OR = 12.70. The patients with single infections had the highest incidence of CIN2+ (34.1%) with respect to those with multiple infections (10.6%).When we studied in the mHPV infection the prevalence of the combinations between the genotypes, we found that in mHPV16 infections, the combinations HPV16, 18 and HPV16, 31 were the most frequent (55.5%) in CIN3 lesion.

CONCLUSIONS

Our results suggest that single HPV infections have a greater risk of developing SCC with respect to multiple infections. Multiple HPV infections are relevant only in the first phase of the lesion (CIN1-CIN2), while they are absent in carcinomas, where infections are of a single genotype. In particular, among multiple infections, HPV16 infection with 2 HR genotypes is associated significantly with CIN2 / CIN3 (21/30) and has 4 times greater risk of developing a high-grade lesion. Thus, it is probable that only specific combinations of HPV (HPV16,18 - HPV 16,31) can be associated with a clinically significant impact, while other combinations can simply be correlated because of a common infection or diagnostic method used. Therefore, multiple HPV16 infections with two high-risk genotypes is a major risk of CIN2/CIN3.