Field experience with the 8-HPV-type oncoprotein test for cervical cancer screening among HPV-positive women living with and without HIV in LMICs.

Overexpression of HPV-oncoproteins E6 and E7 is necessary for HPV-driven cervical carcinogenesis. Hence, these oncoproteins are promising disease-specific biomarkers. We assessed the technical and operational characteristics of the 8-HPV-type OncoE6/E7 Cervical Test in different laboratories using cervical samples from HPV-positive women living with (WLWH) and without HIV. The 8-HPV-type OncoE6/E7 Test (for short: "OncoE6/E7 test") was performed in 2833 HIV-negative women and 241 WLWH attending multicentric studies in Latin America (ESTAMPA study), and in Africa (CESTA study). Oncoprotein positivity were evaluated at each testing site, according to HIV status as well as type-specific agreement with HPV-DNA results. A feedback questionnaire was given to the operators performing the oncoprotein test to evaluate their impression and acceptability regarding the test. The OncoE6/E7 test revealed a high positivity rate heterogeneity across all testing sites (I2: 95.8%, p < .01) with significant lower positivity in WLWH compared to HIV-negative women (12% vs 25%, p < .01). A similar HPV-type distribution was found between HPV DNA genotyping and oncoprotein testing except for HPV31 and 33 (moderate agreement, k = 0.57). Twenty-one laboratory technicians were trained on oncoprotein testing. Despite operators' concerns about the time-consuming procedure and perceived need for moderate laboratory experience, they reported the OncoE6/E7 test as easy to perform and user-friendly for deployment in resource-limited settings. The high positivity rate variability found across studies and subjectivity in test outcome interpretation could potentially results in oncoprotein false positive/negative, and thus the need for further refinements before implementation of the oncoprotein testing in screen-triage-and-treat approaches is warranted.

Folate deficiency modifies the risk of CIN3+ associated with DNA methylation levels: a nested case-control study from the ASCUS-COL trial.

PURPOSE: To our knowledge, there are very few studies evaluating if the levels of folate modify the risk of cervical intraepithelial neoplasia grade 2 and higher (CIN2+ and CIN3+) associated with the levels of HPV genome methylation, two cofactors related to single carbon metabolism and independently associated with cervical cancer in previous studies. We conducted a case-control study nested in a three-arm randomized clinical pragmatic trial (ASCUS-COL trial) to evaluate the risk of CIN3+ associated with methylation levels according to serum folate concentrations. METHODS: Cases (n = 155) were women with histologically confirmed CIN2+ (113 CIN2, 38 CIN3, and 4 SCC) and controls were age and follow-up time at diagnosis-matched women with histologically confirmed ≤ CIN1 (n = 155), selected from the 1122 hrHPV + women of this trial. The concentrations of serum folate were determined by the radioimmunoassay SimulTRAC-SNB-VitaminB12/Folate-RIAKit and the methylation levels by the S5 classifier. Stepwise logistic regression models were used to estimate the association between folate or methylation levels and CIN2+ or CIN3+. The joint effect of folate levels and methylation on the risk of CIN3+ was estimated using combinations of categorical stratifications. RESULTS: Folate levels were significantly lower in women with CIN3+ than in other diagnostic groups (p = 0.019). The risk of CIN3+ was eight times higher (OR 8.9, 95% CI 3.4-24.9) in women with folate deficiency and high methylation levels than in women with normal folate and high methylation levels (OR 1.4, 95% CI 0.4-4.6). CONCLUSION: High methylation and deficient folate independently increased the risk of CIN3+ while deficient folate combined with high methylation was associated with a substantially elevated risk of CIN3+.

Performance of standardised colposcopy to detect cervical precancer and cancer for triage of women testing positive for human papillomavirus: results from the ESTAMPA multicentric screening study.

BACKGROUND: Colposcopy, currently included in WHO recommendations as an option to triage human papillomavirus (HPV)-positive women, remains as the reference standard to guide both biopsy for confirmation of cervical precancer and cancer and treatment approaches. We aim to evaluate the performance of colposcopy to detect cervical precancer and cancer for triage in HPV-positive women. METHODS: This cross-sectional, multicentric screening study was conducted at 12 centres (including primary and secondary care centres, hospitals, laboratories, and universities) in Latin America (Argentina, Bolivia, Colombia, Costa Rica, Honduras, Mexico, Paraguay, Peru, and Uruguay). Eligible women were aged 30-64 years, sexually active, did not have a history of cervical cancer or treatment for cervical precancer or a hysterectomy, and were not planning to move outside of the study area. Women were screened with HPV DNA testing and cytology. HPV-positive women were referred to colposcopy using a standardised protocol, including biopsy collection of observed lesions, endocervical sampling for transformation zone (TZ) type 3, and treatment as needed. Women with initial normal colposcopy or no high-grade cervical lesions on histology (less than cervical intraepithelial neoplasia [CIN] grade 2) were recalled after 18 months for another HPV test to complete disease ascertainment; HPV-positive women were referred for a second colposcopy with biopsy and treatment as needed. Diagnostic accuracy of colposcopy was assessed by considering a positive test result when the colposcopic impression at the initial colposcopy was positive minor, positive major, or suspected cancer, and was considered negative otherwise. The main study outcome was histologically confirmed CIN3+ (defined as grade 3 or worse) detected at the initial visit or 18-month visit. FINDINGS: Between Dec 12, 2012, and Dec 3, 2021, 42 502 women were recruited, and 5985 (14·1%) tested positive for HPV. 4499 participants with complete disease ascertainment and follow-up were included in the analysis, with a median age of 40·6 years (IQR 34·7-49·9). CIN3+ was detected in 669 (14·9%) of 4499 women at the initial visit or 18-month visit (3530 [78·5%] negative or CIN1, 300 [6·7%] CIN2, 616 [13·7%] CIN3, and 53 [1·2%] cancers). Sensitivity was 91·2% (95% CI 88·9-93·2) for CIN3+, whereas specificity was 50·1% (48·5-51·8) for less than CIN2 and 47·1% (45·5-48·7) for less than CIN3. Sensitivity for CIN3+ significantly decreased in older women (93·5% [95% CI 91·3-95·3] in those aged 30-49 years vs 77·6% [68·6-85·0] in those aged 50-65 years; p<0·0001), whereas specificity for less than CIN2 significantly increased (45·7% [43·8-47·6] vs 61·8% [58·7-64·8]; p<0·0001). Sensitivity for CIN3+ was also significantly lower in women with negative cytology than in those with abnormal cytology (p<0·0001). INTERPRETATION: Colposcopy is accurate for CIN3+ detection in HPV-positive women. These results reflect ESTAMPA efforts in an 18-month follow-up strategy to maximise disease detection with an internationally validated clinical management protocol and regular training, including quality improvement practices. We showed that colposcopy can be optimised with proper standardisation to be used as triage in HPV-positive women. FUNDING: WHO; Pan American Health Organization; Union for International Cancer Control; National Cancer Institute (NCI); NCI Center for Global Health; National Agency for the Promotion of Research, Technological Development, and Innovation; NCI of Argentina and Colombia; Caja Costarricense de Seguro Social; National Council for Science and Technology of Paraguay; International Agency for Research on Cancer; and all local collaborative institutions.

Implementing HPV testing in 9 Latin American countries: The laboratory perspective as observed in the ESTAMPA study.

Background: Replacement of cytology screening with HPV testing is recommended and essential for cervical cancer elimination. HPV testing for primary screening was implemented in 12 laboratories within 9 Latin American countries, as part of the ESTAMPA cervical cancer screening study. Our observations provide information on critical operational aspects for HPV testing implementation in diverse resource settings. Methods: We describe the implementation process of HPV testing in ESTAMPA, focusing on laboratory aspects. We assess the readiness of 12 laboratories to start HPV testing and their continuity capacity to maintain good quality HPV testing until end of recruitment or up to December 2021. Readiness was based on a checklist. Information from the study database; regular meetings and monitoring visits; and a questionnaire on laboratory operational aspects sent in May 2020 were used to assess continuity capacity. Compliance with seven basic requirements (readiness) and eight continuity requirements (continuity capacity) was scored (1 = compliant, 0 = not compliant) and totaled to classify readiness and continuity capacity as very limited, limited, moderate or high. Experiences, challenges, and enablers of the implementation process are also described. Results: Seven of 12 laboratories had high readiness, three moderate readiness, and of two laboratories new to HPV testing, one had limited readiness and the other very limited readiness. Two of seven laboratories with high readiness also showed high continuity capacity, one moderate continuity capacity, and the other four showed limited continuity capacity since they could not maintain good quality HPV testing over time. Among three laboratories with moderate readiness, one kept moderate continuity capacity and two reached high continuity capacity. The two laboratories new to HPV testing achieved high continuity capacity. Based on gained expertise, five laboratories have become part of national screening programs. Conclusion: High readiness of laboratories is an essential part of effective implementation of HPV testing. However, high readiness is insufficient to guarantee HPV testing high continuity capacity, for which a "culture of quality" should be established with regular training, robust monitoring and quality assurance systems tailored to local context. All efforts to strengthen HPV laboratories are valuable and crucial to guarantee effective implementation of HPV-based cervical screening.

Inflammatory biomarkers and risk of breast cancer among young women in Latin America: a case-control study.

BACKGROUND: Breast cancer incidence is increasing rapidly in Latin America, with a higher proportion of cases among young women than in developed countries. Studies have linked inflammation to breast cancer development, but data is limited in premenopausal women, especially in Latin America. METHODS: We investigated the associations between serum biomarkers of chronic inflammation (interleukin (IL)-6, IL-8, IL-10, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), leptin, adiponectin) and risk of premenopausal breast cancer among 453 cases and 453 matched, population-based controls from Chile, Colombia, Costa Rica, and Mexico. Odds ratios (OR) were estimated using conditional logistic regression models. Analyses were stratified by size and hormonal receptor status of the tumors. RESULTS: IL-6 (ORper standard deviation (SD) = 1.33 (1.11-1.60)) and TNF-α (ORper SD = 1.32 (1.11-1.58)) were positively associated with breast cancer risk in fully adjusted models. Evidence of heterogeneity by estrogen receptor (ER) status was observed for IL-8 (P-homogeneity = 0.05), with a positive association in ER-negative tumors only. IL-8 (P-homogeneity = 0.06) and TNF-α (P-homogeneity = 0.003) were positively associated with risk in the largest tumors, while for leptin (P-homogeneity = 0.003) a positive association was observed for the smallest tumors only. CONCLUSIONS: The results of this study support the implication of chronic inflammation in breast cancer risk in young women in Latin America. Largest studies of prospective design are needed to confirm these findings in premenopausal women.

Consumption of industrial processed foods and risk of premenopausal breast cancer among Latin American women: the PRECAMA study.

Ultra-processed food intake has been linked to an increased risk of breast cancer in Western populations. No data are available in the Latin American population although the consumption of ultra-processed foods is increasing rapidly in this region. We evaluated the association of ultra-processed food intake to breast cancer risk in a case-control study including 525 cases (women aged 20-45 years) and 525 matched population-based controls from Chile, Colombia, Costa Rica and Mexico. The degree of processing of foods was classified according to the NOVA classification. Overall, the major contributors to ultra-processed food intake were ready-to-eat/heat foods (18.2%), cakes and desserts (16.7%), carbonated and industrial fruit juice beverages (16.7%), breakfast cereals (12.9%), sausages and reconstituted meat products (12.1%), industrial bread (6.1%), dairy products and derivatives (7.6%) and package savoury snacks (6.1%). Ultra-processed food intake was positively associated with the risk of breast cancer in adjusted models (OR T3-T1=1.93; 95% CI=1.11 to 3.35). Specifically, a higher risk was observed with oestrogen receptor positive breast cancer (ORT3-T1=2.44, (95% CI=1.01 to 5.90, P-trend=0.049), while no significant association was observed with oestrogen receptor negative breast cancer (ORT3-T1=1.87, 95% CI=0.43 to 8.13, P-trend=0.36). Our findings suggest that the consumption of ultra-processed foods might increase the risk of breast cancer in young women in Latin America. Further studies should confirm these findings and disentangle specific mechanisms relating ultra-processed food intake and carcinogenic processes in the breast.

Effective methylation triage of HPV positive women with abnormal cytology in a middle-income country.

The S5-methylation test, an alternative to cytology and HPV16/18 genotyping to triage high-risk HPV-positive (hrHPV+) women, has not been widely validated in low-middle-income countries (LMICs). We compared S5 to HPV16/18 and cytology to detect cervical intraepithelial neoplasia Grade 2 or worse (CIN2+) and CIN3+ in hrHPV+ women selected from a randomized pragmatic trial of 2661 Colombian women with an earlier-borderline abnormal cytology. We included all hrHPV+ CIN2 and CIN3+ cases (n = 183) age matched to 183

Multicentric study of cervical cancer screening with human papillomavirus testing and assessment of triage methods in Latin America: the ESTAMPA screening study protocol.

INTRODUCTION: Human papillomavirus (HPV) testing is replacing cytology in primary screening. Its limited specificity demands using a second (triage) test to better identify women at high-risk of cervical disease. Cytology represents the immediate triage but its low sensitivity might hamper HPV testing sensitivity, particularly in low-income and middle-income countries (LMICs), where cytology performance has been suboptimal. The ESTAMPA (EStudio multicéntrico de TAMizaje y triaje de cáncer de cuello uterino con pruebas del virus del PApiloma humano; Spanish acronym) study will: (1) evaluate the performance of different triage techniques to detect cervical precancer and (2) inform on how to implement HPV-based screening programmes in LMIC. METHODS AND ANALYSIS: Women aged 30-64 years are screened with HPV testing and Pap across 12 study centres in Latin America. Screened positives have colposcopy with biopsy and treatment of lesions. Women with no evident disease are recalled 18 months later for another HPV test; those HPV-positive undergo colposcopy with biopsy and treatment as needed. Biological specimens are collected in different visits for triage testing, which is not used for clinical management. The study outcome is histological high-grade squamous intraepithelial or worse lesions (HSIL+) under the lower anogenital squamous terminology. About 50 000 women will be screened and 500 HSIL+ cases detected (at initial and 18 months screening). Performance measures (sensitivity, specificity and predictive values) of triage techniques to detect HSIL+ will be estimated and compared with adjustment by age and study centre. ETHICS AND DISSEMINATION: The study protocol has been approved by the Ethics Committee of the International Agency for Research on Cancer (IARC), of the Pan American Health Organisation (PAHO) and by those in each participating centre. A Data and Safety Monitoring Board (DSMB) has been established to monitor progress of the study, assure participant safety, advice on scientific conduct and analysis and suggest protocol improvements. Study findings will be published in peer-reviewed journals and presented at scientific meetings. TRIAL REGISTRATION NUMBER: NCT01881659.

Anthropometry, body shape in early-life and risk of premenopausal breast cancer among Latin American women: results from the PRECAMA study.

Cumulating evidence in Caucasian women suggests a positive association between height and premenopausal breast cancer risk and a negative association with overall adiposity; however data from Latin America are scarce. We investigated the associations between excess adiposity, body shape evolution across life, and risk of premenopausal breast cancer among 406 cases (women aged 20-45) and 406 matched population-based controls from Chile, Colombia, Costa Rica, and Mexico. Negative associations between adult adiposity and breast cancer risk were observed in adjusted models (body mass index (BMI): Odds ratio (OR) per 1 kg/m2 = 0.93; 95% confidence interval = 0.89-0.96; waist circumference (WC): OR per 10 cm = 0.81 (0.69-0.96); hip circumference (HC): OR per 10 cm = 0.80 (0.67-0.95)). Height and leg length were not associated with risk. In normal weight women (18.5 ≤ BMI < 25), women with central obesity (WC > 88 cm) had an increased risk compared to women with normal WC (OR = 3.60(1.47-8.79)). Residuals of WC over BMI showed positive associations when adjusted for BMI (OR per 10 cm = 1.38 (0.98-1.94)). Body shape at younger ages and body shape evolution were not associated with risk. No heterogeneity was observed by receptor status. In this population of Latin American premenopausal women, different fat distributions in adulthood were differentially associated with risk of breast cancer.

Project profile: a multicenter study on breast cancer in young women in Latin America (PRECAMA study).

OBJECTIVE: To describe the rationale and the methodology of a multicenter project to study the etiology of breast cancer in young Latin American women. MATERIALS AND METHODS: The International Agency for Research on Cancer has established an international collaborative population-based case-control study in four countries in Latin America: Chile, Colombia, Costa Rica, and Mexico (the PRECAMA study). Standardized methodologies were developed to collect information on reproductive variables, lifestyle, anthropometry, diet, clinical and pathological data, and biological specimens. The study will be extended to other countries in the region. CONCLUSIONS: PRECAMA is unique in its multidisciplinary approach that combines genetics, genomics, and metabolomics with lifestyle factors. Then data generated through this project will be instrumental to identify major risk factors for molecular subtypes of breast cancer in young women, which will be important for pre- vention and targeted screening programs in Latin America.

OBJETIVO: Describir la justificación y la metodología para el establecimiento de un proyecto multicéntrico sobre el cáncer de mama en mujeres jóvenes de América Latina. MATERIAL Y MÉTODOS: La Agencia Internacional para la Investigación del Cáncer (IARC) ha establecido un estudio colaborativo internacional de casos y controles con base poblacional en cuatro países de América Latina: Chile, Colombia, Costa Rica y México (el estudio PRECAMA). Se han desarrollado metodologías estandarizadas para recolectar información sobre variables reproductivas, estilos de vida, antropometría y dieta, datos clínicos y patológicos y muestras biológicas. CONCLUSIONES: PRECAMA es único en su enfoque multidisciplinario. Los datos generados a través de este proyecto serán fundamentales para identificar los principales factores de riesgo del cáncer de mama en mujeres jóvenes. Los hallazgos serán relevantes para la prevención y los programas de detección oportuna en América Latina, con beneficios clínicos inmediatos.

Project profile: a multicenter study on breast cancer in young women in Latin America (PRECAMA study) / Perfil de Proyecto: Un estudio multicéntrico sobre el cáncer de mama en mujeres jóvenes en América Latina (estudio PRECAMA)

Abstract: Objective: To describe the rationale and the methodology of a multicenter project to study the etiology of breast cancer in young Latin American women. Materials and methods: The International Agency for Research on Cancer has established an international collaborative population-based case-control study in four countries in Latin America: Chile, Colombia, Costa Rica, and Mexico (the PRECAMA study). Standardized methodologies were developed to collect information on reproductive variables, lifestyle, anthropometry, diet, clinical and pathological data, and biological specimens. The study will be extended to other countries in the region. Conclusion: PRECAMA is unique in its multidisciplinary approach that combines genetics, genomics, and metabolomics with lifestyle factors. The data generated through this project will be instrumental to identify major risk factors for molecular subtypes of breast cancer in young women, which will be important for prevention and targeted screening programs in Latin America.

Resumen: Objetivo: Describir la justificación y la metodología para el establecimiento de un proyecto multicéntrico sobre el cáncer de mama en mujeres jóvenes de América Latina. Material y métodos: La Agencia Internacional para la Investigación del Cáncer (IARC) ha establecido un estudio colaborativo internacional de casos y controles con base poblacional en cuatro países de América Latina: Chile, Colombia, Costa Rica y México (el estudio PRECAMA). Se han desarrollado metodologías estandarizadas para recolectar información sobre variables reproductivas, estilos de vida, antropometría y dieta, datos clínicos y patológicos y muestras biológicas. Conclusión: PRECAMA es único en su enfoque multidisciplinario. Los datos generados a través de este proyecto serán fundamentales para identificar los principales factores de riesgo del cáncer de mama en mujeres jóvenes. Los hallazgos serán relevantes para la prevención y los programas de detección oportuna en América Latina, con beneficios clínicos inmediatos.

Perception about barriers and facilitators of the school-based HPV vaccine program of Manizales, Colombia: A qualitative study in school-enrolled girls and their parents.

In 2012, Colombia implemented a school-based HPV vaccination program of a 3-dose series for nine year old girls. Following a mass psychogenic response after vaccination in a Colombian town, vaccination rates dropped from 80% in 2012-2013 to 5% in 2016. The study aimed to identify barriers and facilitators of HPV vaccine uptake among girls eligible for vaccination in the initial years of vaccine implementation from 2012 to 2014, and their parents. We conducted 19 individual qualitative interviews and 18 focus groups with an average of 5 girls, in Manizales, Colombia between 2016 and 2017. In total, 49 girls from six schools and 58 of their parents participated in the study. Participants had some degree of awareness about cervical cancer, especially among those of middle and upper socioeconomic level. However, the vaccine was known as a prevention measure only after pap-smears and condoms. The main facilitator for vaccine uptake for parents was the desire to prevent diseases in general and for girls, it was facilitated by receiving positive information about the vaccine. The main barriers for vaccine uptake or for three doses completion were the event in Carmen de Bolivar, fear of adverse effects and fear of needles. Girls and parents stated that they received little or no information from schools or health care services about the HPV vaccine prior to vaccination. Our results suggest that improving HPV vaccination rates in Colombia will require a comprehensive education program including mass media information about HPV vaccine.

Reproductive factors and molecular subtypes of breast cancer among premenopausal women in Latin America: the PRECAMA study.

Etiological differences among breast cancer (BC) subtypes have not been clearly established, especially among young women in Latin America. This study examined the relationship between reproductive factors and BC subtypes among 288 BC cases (20-45 years) and population-based matched controls in four Latin American countries. Immunohistochemistry was determined centrally. Associations between BC and reproductive factors were determined. Older age at first full-term pregnancy (FFTP) (Odds Ratio (OR) = 1.11; 95% Confidence Interval (CI), 1.04-1.19 per year), longer time between menarche and FFTP (OR = 1.12; 95%CI: 1.04-1.20 per year), and older age at last pregnancy (OR = 1.10; 95%CI, 1.02-1.19 per year) were associated with an increased risk of estrogen receptor positive (ER+) tumors (n = 122). Ever pregnant (OR = 0.35; 95%CI, 0.13-0.96), number of childbirths (OR = 0.64; 95%CI, 0.47-0.87 per child), time since last birth (OR = 0.92; 95%CI, 0.85-0.99 per year), and history of breastfeeding (OR = 0.23; 95%CI, 0.09-0.58) were inversely associated with the risk of ER+ tumor. Older age at menarche (OR = 0.63; 95%CI, 0.45-0.89 per year) and longer duration of breastfeeding (OR = 0.97; 95%CI, 0.94-1.01 per month) were inversely associated with estrogen receptor negative (ER-) tumors (n = 48). Reproductive factors may be differentially associated with BC subtypes in young Latin American women.

Secular trends of HPV genotypes in invasive cervical cancer in Cali, Colombia 1950-1999.

UNLABELLED: Aim To estimate relative contribution and time trends of HPV types in cervical cancer in Cali, Colombia over a 50 years' period. METHODS: Paraffin blocks of 736 cervical cancer histological confirmed cases were retrieved from the pathology laboratory at Hospital Universitario del Valle (Cali, Colombia) and HPV genotyped using SPF10-PCR/DEIA/LiPA25 (version 1) assay. Marginal effect of age and year of diagnosis in secular trends of HPV type prevalence among HPV+ cases were assessed by robust Poisson regression analysis. RESULTS: 64.7% (95%CI: 59.9-69.2) of squamous cell carcinomas (SCCs) were attributed to HPV 16 and 18, 78.2% (95%CI: 74-82) to HPV 16, 18, 31, 33 and 45 and 84.8% (95%CI: 81-88.1) to HPV 16, 18, 31, 33, 45, 52 and 58 while ninety-three percent of adenocarcinomas (ADCs) were attributed to HPV 16, 18 and 45 only. The prevalence of specific HPV types did not change over the 50-year period. A significant downward trend of prevalence ratios of HPV16 (​P=0.017) and α7 but HPV 18 (i.e., HPV 39, 45, 68, 70, ​P=0.024) with increasing age at diagnosis was observed. In contrast, the prevalence ratio to other HPV genotypes of α9 but HPV 16 genotypes (i.e., HPV 31, 33, 35, 52, 58, 67, ​P=0.002) increased with increasing age at diagnosis. CONCLUSION: No changes were observed in the relative contribution of HPV types in cervical cancer in Cali, Colombia during the 50 years. In this population, an HPV vaccine including the HPV 16, 18, 31, 33, 45, 52 and 58 genotypes may have the potential to prevent ∼85% and 93% of SCC and ADC cases respectively.

Nuevos paradigmas y desafíos en la prevención y control del cáncer de cuello uterino en América Latina / New paradigms and challenges in cervical cancer prevention and control in Latin America

El cáncer de cuello uterino sigue siendo un problema de salud pública en Latinoamérica. El uso de la citología para la detección de lesiones pre-cancerosas no ha tenido mayor impacto en las tasas de incidencia y mortalidad, que aún se mantienen altas en la región. La disponibilidad de nuevas técnicas de tamizaje para la detección de lesiones pre-cancerosas y de vacunas altamente eficaces que previenen casi todas las lesiones relacionadas con VPH-16 y VPH-18 en mujeres no expuestas previamente al virus representan una gran oportunidad para la prevención del cáncer de cuello uterino en la región. En este manuscrito resumimos la evidencia científica y la experiencia de la región en i) el uso de pruebas de VPH y de la inspección visual después del ácido acético (IVAA) en tamizaje primario, y ii) la implementación de programas de vacunación en adolescentes. Finalmente enumeramos una serie de recomendaciones adecuadas para distintos escenarios. La factibilidad de implementar un programa nacional de prevención de cáncer de cuello uterino exitoso y sostenible en países latinoamericanos dependerá de las prioridades de salud, la infraestructura y personal de salud disponible, determinadas luego de un riguroso análisis situacional local.

Cervical cancer continues to be a significant health problem in Latin America. The use of conventional cytology to detect precancerous cervical lesions has had almost no major impact on reducing cervical cancer incidence and mortality rates, which are still high in the region. The availability of new screening tools to detect precancerous lesions provide great opportunities for cervical cancer prevention in the region, as do highly efficacious HPV vaccines able to prevent nearly all lesions associated with HPV-16 and -18 when applied before viral exposure. This paper summarizes the scientific evidence and regional experiences related to: i) the use of HPV testing and visual inspection after the application of acetic acid (VIA) in primary screening and ii) the implementation of adolescent HPV vaccination programs. Finally, we outline a number of recommendations for different resource settings. The feasibility of implementing successful and sustainable national cervical cancer prevention programs in Latin American countries in the region will depend on health priorities and the availability of infrastructure and health personnel-as determined by rigorous local situational analysis.

[New paradigms and challenges in cervical cancer prevention and control in Latin America]. / Nuevos paradigmas y desafíos en la prevención y control del cáncer de cuello uterino en América Latina.

Cervical cancer continues to be a significant health problem in Latin America. The use of conventional cytology to detect precancerous cervical lesions has had almost no major impact on reducing cervical cancer incidence and mortality rates, which are still high in the region. The availability of new screening tools to detect precancerous lesions provide great opportunities for cervical cancer prevention in the region, as do highly efficacious HPV vaccines able to prevent nearly all lesions associated with HPV-16 and -18 when applied before viral exposure. This paper summarizes the scientific evidence and regional experiences related to: i) the use of HPV testing and visual inspection after the application of acetic acid (VIA) in primary screening and ii) the implementation of adolescent HPV vaccination programs. Finally, we outline a number of recommendations for different resource settings. The feasibility of implementing successful and sustainable national cervical cancer prevention programs in Latin American countries in the region will depend on health priorities and the availability of infrastructure and health personnel--as determined by rigorous local situational analysis.

Estructura moleuular y antigénica de la vacuna ontra el virus del papiloma hummano 16 (vph 16) / Antigenic and Molecular Structure of Human Papillomavirus (HPV) 16 Vaccine

La proteína L1 del Virus del Papiloma Humano (VPH) constituye el 80% de la cápside viral. Las vacunas profilácticas contra el VPH son sintetizadas a partir de la proteína L1 ensamblada en Partículas similares al Virus (del inglés VLP), las cuales son altamente inmunogénicas generando anticuerpos específicos de tipo y en algunos casos pueden presentar reacción cruzada entre tipos de VPH filogenéticamente próximos. La estructura de la proteína L1 del VPH es importante porque confiere estabilidad a la cápside mediante el establecimiento de interacciones intra e intercapsoméricas lo que asegura la integridad viral y antigénicamente porque contiene los epítopes que inducen la respuesta inmune protectora. En estudios en los que se evaluó la antigenicidad de la proteína L1 se determinó que los epítopes inmunodominantes de la cápside viral se encuentran en los bucles B-C, D-E, F-G, H-I y en el extremo C-terminal. Estos bucles son poco conservados entre los diferentes genotipos y se encuentran en segmentos de la proteína expuestos en la superficie de la cápside. Los aminoácidos situados en los bucles B-C, F-G y H-I son primordiales para el reconocimiento por los anticuerpos neutralizantes. Los diferentes subtipos y variantes presentan cambios en estos aminoácidos o en residuos que conforman otros epítopes. En esta revisión se presentará un estado del arte de la proteína L1 del VPH genotipo 16, la estructura y su importancia en el desarrollo de vacunas contra la infección producida por este virus.

Human Papillomavirus L1 protein makes up 80% of the viral capsid and self assembles in Virus-like Particles (VLP); these particles are immunogenic, generate type-specific antibodies and can induce very limited cross-reactivity among highly homologous HPV types. In addition to its structural function, it confers the stability to the capsid by establishing disulfide bonds and other intra and intercapsomeric interactions, and also contains the epitopes that induce the protective immune response of prophylactic vaccines. Immunological studies of this protein have concluded that the main epitopes of the HPV viral capsid are found in the loops B-C, D-E, F-G, H-I and the C-terminal arm. These loops are exposed on the surface of the viral capsid and have a low degree of conservation among the different genotypes. Specifically, amino acid 50 located on loop B-C and aminoacids 266, 271 and 288 located on loop F-G are important for the recognition on neutralizing antibodies. The different genotypes and variants exhibit mutations on these residues.

New approaches to cervical cancer screening in Latin America and the Caribbean.

Cervical cancer remains an important public health problem in the Latin America and Caribbean region (LAC), with an expected significant increase in disease burden in the next decades as a result of population ageing. Prophylactic human papillomavirus (HPV) vaccine is currently unaffordable in LAC countries. However, even if vaccination was implemented, an additional two decades will be required to observe its impact on HPV related disease and cancer. With some exceptions, cytology-based screening programs have been largely ineffective to control the problem in the region, and there is a need for new approaches to the organization of screening and for use of newly developed techniques. Several research groups in LAC have conducted research on new screening methods, some of which are summarized in this paper. A recommendation to reorganize screening programs is presented considering visual inspection for very low resource areas, improvement of cytology where it is operating successfully and HPV DNA testing followed by visual inspection with acetic acid (VIA) or cytology as soon as this method becomes technically and economically sustainable. This could be facilitated by the incorporation of new, low-cost HPV DNA testing methods and the use of self-collected vaginal specimens for selected groups of the population. An important requisite for screening based on HPV testing will be the quality assurance of the laboratory and the technique by validation and certification measures.

Integration of human papillomavirus vaccination and cervical cancer screening in Latin America and the Caribbean.

Despite substantial efforts to control cervical cancer by screening, most Latin American and Caribbean countries continue to experience incidence rates of this disease that are much higher than those of other Western countries. The implementation of universal human papillomavirus (HPV) vaccination for young adolescent women is the best prospect for changing this situation. Even though there are financial challenges to overcome to implement such a policy, there is broad political support in the region for adopting universal HPV vaccination. The costs of implementing this policy could be largely alleviated by changing cervical cancer control practices that rely on inefficient use of resources presently allocated to cytology screening. In view of the strong evidence base concerning cervical cancer prevention technologies in the region and the expected impact of vaccination on the performance of cytology, we propose a reformulation of cervical cancer screening policies to be based on HPV testing using validated methods followed by cytologic triage. This approach would serve as the central component of a system that plays the dual role of providing screening and surveillance as integrated and complementary activities sharing centralized resources and coordination.

Molecular and serological evidence of the epidemiological association of HPV 13 with focal epithelial hyperplasia: a case-control study.

BACKGROUND: Focal epithelial hyperplasia is a benign proliferative condition that is more frequently found in children of certain ethnic groups. Human papillomavirus 13 and 32 DNA has been consistently detected in these lesions. OBJECTIVE: To demonstrate the epidemiological association of HPV 13 with FEH in the Emberá-Chamí community of Antioquia, Colombia. METHODS: A population-based, case-control study was conducted. One hundred and thirty-eight children were screened and 17 clinical and histologically-confirmed cases were sex and age-matched with 27 controls. Biopsies from FEH lesions and mouth washes from controls were obtained for DNA analysis. HPV 13 DNA was identified using a previously described type-specific PCR test. HPV 13 VLPs were produced by cloning of L1 from the HPV 13 cloned genome and seroreactivity against HPV 13 VLPs of sera from cases and controls were evaluated by ELISA. RESULTS: Among the whole population the prevalence of FEH was 13%. One-hundred-percent of the cases and 29.6% of the controls were HPV 13 positive. There was a significant difference in HPV DNA status between cases and controls (one-tailed Fisher exact test: P<0.0001). Antibodies against HPV 13 VLPs were found in 58.8% of cases and in 33.3% of controls, this difference was not statistically significant (P=0.089 Fisher exact test). However, the median of the ODs of the ELISA positive sera of the cases was 0.596 (interquartile range: 0.5075-0.8245) versus 0.452 (interquartile range: 0.337-0.479) in the controls and this was significantly different (P=0.0041 Man-Whitney test). CONCLUSIONS: We demonstrated a risk for association of FEH with infection with HPV 13. The higher level of antibodies against HPV 13 VLPs in cases may suggest the requirement of higher viral load or viral persistence for disease development.