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Human Papillomavirus (HPV) is the most common sexually transmitted infection worldwide and it is responsible for most cases of uterine cancer. In Ecuador there is limited information about HPV types (and variants) in cancerous lesions; however, identifying the type-specific HPV prevalence in cervical lesions of women living in Ecuador is important to better predict the impact of HPV prophylactic vaccination in this country. We studied the prevalence of HPV types in cervical cancerous or precancerous lesions from 164 Ecuadorian women and found that 86.0% were HPV positive. The most common types were HPV16 (41.8%) and HPV58 (30.5%). Interestingly, HPV18 was detected only in 2.8% of the HPV-positive samples. Fifteen DNA sequences (genes E6 and L1) from 16 samples positive for HPV16 belonged to the European lineage, considered one of the least carcinogenic lineages, and 1 (6.25%) to the Asian-American lineage. Similar analysis in 12 HPV58 positive samples showed that 10 (83.3%) sequences grouped in sublineage A2, which belongs to the oldest HPV58 lineage, 1 belonged to A3 and 1 to lineage C. This study suggests that the currently used HPV vaccines (bivalent and tetravalent) may have lower effectiveness in Ecuador than in other geographic locations where HPV18 is more prevalent.

Knowledge about human papillomaviruses (HPV) types involved in anal cancers in some world regions is scanty. Here, we describe the HPV DNA prevalence and type distribution in a series of invasive anal cancers and anal intraepithelial neoplasias (AIN) grades 2/3 from 24 countries. We analyzed 43 AIN 2/3 cases and 496 anal cancers diagnosed from 1986 to 2011. After histopathological evaluation of formalin-fixed paraffin-embedded samples, HPV DNA detection and genotyping was performed using SPF-10/DEIA/LiPA25 system (version 1). A subset of 116 cancers was further tested for p16(INK4a) expression, a cellular surrogate marker for HPV-associated transformation. Prevalence ratios were estimated using multivariate Poisson regression with robust variance in the anal cancer data set. HPV DNA was detected in 88.3% of anal cancers (95% confidence interval [CI]: 85.1-91.0%) and in 95.3% of AIN 2/3 (95% CI: 84.2-99.4%). Among cancers, the highest prevalence was observed in warty-basaloid subtype of squamous cell carcinomas, in younger patients and in North American geographical region. There were no statistically significant differences in prevalence by gender. HPV16 was the most frequent HPV type detected in both cancers (80.7%) and AIN 2/3 lesions (75.4%). HPV18 was the second most common type in invasive cancers (3.6%). p16(INK4a) overexpression was found in 95% of HPV DNA-positive anal cancers. In view of the results of HPV DNA and high proportion of p16(INK4a) overexpression, infection by HPV is most likely to be a necessary cause for anal cancers in both men and women. The large contribution of HPV16 reinforces the potential impact of HPV vaccines in the prevention of these lesions.

Human Papillomavirus (HPV) is the most common sexually transmitted infection worldwide and it is responsible for most cases of uterine cancer. In Ecuador there is limited information about HPV types (and variants) in cancerous lesions; however, identifying the type-specific HPV prevalence in cervical lesions of women living in Ecuador is important to better predict the impact of HPV prophylactic vaccination in this country. We studied the prevalence of HPV types in cervical cancerous or precancerous lesions from 164 Ecuadorian women and found that 86.0% were HPV positive. The most common types were HPV16 (41.8%) and HPV58 (30.5%). Interestingly, HPV18 was detected only in 2.8% of the HPV-positive samples. Fifteen DNA sequences (genes E6 and L1) from 16 samples positive for HPV16 belonged to the European lineage, considered one of the least carcinogenic lineages, and 1 (6.25%) to the Asian-American lineage. Similar analysis in 12 HPV58 positive samples showed that 10 (83.3%) sequences grouped in sublineage A2, which belongs to the oldest HPV58 lineage, 1 belonged to A3 and 1 to lineage C. This study suggests that the currently used HPV vaccines (bivalent and tetravalent) may have lower effectiveness in Ecuador than in other geographic locations where HPV18 is more prevalent.