Integration of human papillomavirus (HPV) DNA into human cells accompanied by the disruption of the viral genome has been described as a prerequisite for cancer development. This study aimed to investigate E2 gene integrity of HPV16 and HPV58 viruses isolated from infected women with cervical lesions. Forty-two HPV16- and 31 HPV58-positive samples were analysed. E2 integrity was assumed when all fragments covering the E2 gene were amplified with specific polymerase chain reaction primers. Overall, in 59% of the samples, at least one fragment was not amplified in HPV16- (57%) and HPV58-positive samples (61%). Samples from high-grade squamous intraepithelial lesions had the highest frequency of E2 gene disruptions (73%), followed by samples from low-grade squamous intraepithelial lesions (63%) and, finally, samples from invasive cervical cancer (35%). Association between the integrity status of the E2 gene, and lesion grade was assessed by the chi-squared test applied to the combined set of viruses (p = 0.6555) or to populations of the same virus type (HPV58, p = 0.3101; HPV16, p = 0.3024). In conclusion, in this study, no association was found between the presence of E2 gene disruptions and the grade of cervical lesions caused by HPV16 and HPV58.

Infection with some genotypes of human papillomavirus (HPV) is the most important risk factor associated with cervical cancer (CC). Throughout the world, HPV type 58 prevalence varies from one region to another; it is higher in women from certain countries in Asia and Latin America, such as China and Mexico. Although intratypic variants have been reported on a few occasions, our knowledge about HPV 58 genetic variation remains limited. Therefore, this work aims to (i) determine the prevalence of HPV type 58 amongst Mexican women with invasive CC or precursor lesions and (ii) identify HPV 58 sequence variants. One hundred and forty five colposcopy clinic patients were studied. Genotyping of HPV 16, 18 and 58 was determined by specific nested PCR and HPV 58 variants were detected by direct sequencing. The general prevalence of HPV was 51.7% (75/145). HPV 16 was found in 30.6% (23/75) and HPV 58 in 24% (18/75) of the patients. HPV 18 was not identified in patients with cervical intraepithelial neoplasia (CIN) grade I; it was only found in those with CIN II, with a prevalence of 6.8% (3/44). In patients with CC, the prevalence of HPV 16 and 58 was 78.9%. Regarding HPV 58 variants, 94.4% of the HPV 58 sequences were identical to the prototype strain, whereas one sample showed changes at a single nucleotide. This study demonstrates a high prevalence of HPV 58 and a low genetic variability of E6 sequences amongst Mexican colposcopy patients.

El objetivo de este estudio es determinar las variables epidemiológicas asociadas a la infección por papilomavirus humano en un grupo de mujeres mexicanas. En un estudio prospectivo, transversal y comparativo, se estudiaron 470 mujeres que acudieron para valoración citológica y colposcópica; previo al examen ginecológico se les realizó una entrevista en la cual se consignó la ficha de identidad, historia reproductiva, anticonceptiva, sexual, tabaquismo pasivo y activo. El diagnóstico de papilomavirus se realizó por citología y colposcopia. Las mujeres infectadas fueron más jóvenes y tuvieron menos embarazos y partos que las mujeres sanas. En el análisis multivariado la edad de las pacientes y la edad del primer embarazo resultaron ser factores protectores contra la infección. A diferencia de otras investigaciones, este estudio no encontró ninguna asociación entre la infección con papilomavirus y la conducta sexual.

The purpose of the study is to determine the epidemiological variables associated to human papillomavirus infection in a group of Mexican women. A cross-sectional study was conducted in 470 women enrolled for Pap smear and colposcopy. Previous to gynecological examination women were interviewed about demographic data, reproductive and contraceptive history, sexual behavior and smoking. The diagnosis of papillomavirus was done by cytology and colposcopy. Women infected were younger and had less pregnancies and childbirth than healthy women. In a multivariate logistic regression analysis, the age of patients and the age of their first pregnancy were protective factors against the infection. Unlike previous research, this study found no associations between human papillomavirus and sexual behavior.