To characterize the likelihood of HPV16/18 to express E6 protein in single and multiple type HPV infections, and to analysis their risk of cervical disease.
Women with normal histology (n=773), CIN1 (n=62), CIN2/3 (n=130), and cervical cancer (n=466) were analyzed for presence of 14 types of high-risk HPV DNA and HPV16/18 E6 oncoprotein using BD onclarityTM and OncoE6TM assay.
Of 1431 subjects, 546 (38.16%) tested positive for HPV16/18. The frequency of E6 oncoprotein expression was significantly higher in single infections than in multiple infections for both HPV16-E6 and HPV18-E6 (HPV16: 80.2% vs. 61.6%, p<0.001; HPV18: 75.7% vs. 47.6%, p=0.011). In HPV16/18 coinfection, the positivity rate was 44.4% for HPV16-E6 protein and 40.7% for HPV18-E6 protein. Only two cases showed expression of HPV16-E6 and of HPV18-E6 at the same time. The overall positivity rate of HPV16 and HPV18 oncoprotein expression in HPV16/18 coinfection subjects was 77.8%, almost the same as in single infection (HPV16: 80.2%; HPV18: 75.7%). Multiple HPV infection clusters most likely to express E6 were HPV16/52 (71.4%), followed by HPV16/51 (60.0%), and the less were HPV16/45 (14.3%). In CIN2+, E6 positivity was 86.5% for HPV16 and 89.7% for HPV18 single infection, significantly higher than 70.5% for HPV16 (P<0.001) and 56.6%% for HPV18 in multiple infections (P=0.004).
HPV16/18 E6 is more likely to express in women with single HPV infection than in women with multiple HPV. Multiple HPV infection clusters show distinctive propensity to express E6 oncoproteins. This could relate to possible intergenotypic competition as consequence multiple infections.