Human papillomaviruses and cancer in Uganda

Prevalence of oncogenic human papillomavirus genotypes in patients diagnosed with anogenital malignancies in Botswana

BACKGROUND

Human papillomavirus (HPV) associated malignancies are the leading cause of cancer death in Botswana. We sought to determine causative HPV types in patients with anogenital malignancies in Botswana to inform vaccine strategy.

METHODS

We used formalin-fixed and paraffin-embedded (FFPE) tissue blocks from patients diagnosed with anal, penile and vulvar squamous cell carcinomas between the years, 2014 and 2016. Presence of HPV 16, 18, or other high-risk (HR) types was detected using Abbott m2000 real-time PCR platform. Tissues with other high-risk types were subsequently analysed using a multiplex qPCR assay that includes 15 validated fluorophore probes.

RESULTS

A total of 126 tissue specimens, comprising of 21 anal (9 males, 12 females), 31 penile and 74 vulvar were studied. Ninety-three (73.8%) patients had their HIV status documented in the records while the rest did not. Eighty-three (83) out of 93 were HIV positive, a prevalence of 89.4% (95% CI: 81-94). HPV was detected in 68/126 (54%) tissues, of which 69% (95% CI: 54-79) had HPV 16 only, 28% (95% CI: 19-40) had other hr.-HPV types and 2.9% (95% CI, 3.5-10.1) were co-infected with HPV 16 and other hr.-types. Other high-risk types detected included HPV 26, 31, 33, 35, 39, 45, 51, 52, 66 and 68. HPV 18 was not detected. Multiple-type HPV infection was detected in 44 of 47 (93.6%) HIV positive participants co-infected with HPV. In HIV-negative individuals, only HPV 16 was detected.

CONCLUSION

In our study, anogenital carcinomas were associated with HPV 16 and other hr.-HPV types besides HPV 16 and 18. HIV co-infected patients had multiple hr.-HPV types detected whereas in HIV-negative patients only HPV 16 was detected. Our study suggests that multivalent vaccines may be more suitable in this setting, especially for HIV-infected individuals.

Human Papillomavirus (HPV) Infection: Molecular Epidemiology, Genotyping, Seroprevalence and Associated Risk Factors among Arab Women in Qatar

Human Papillomavirus (HPV) infections are known to cause cervical cancer worldwide, however, limited information is currently available on prevalence, types distribution and risk factors for HPV infection in the Arab countries. We conducted a cross-sectional observational study exclusively of women of Arabic origin residing in Qatar (n = 406) who were selected from the Women’s Hospital at Hamad Medical Corporation (HMC) and Health Centers of the Primary Health Care Corporation in Doha, Qatar over the period March 2013 to August 2014. Socio-demographic, behavioral and clinical data were collected. Four hundred and six cervical smears and 292 blood samples were included in the study. HPV typing was done using HPV type-specific primers-based real-time PCR, and Sanger sequencing. HPV-IgG and IgM were quantified using ELISA assays. The prevalence of HPV infection amongst Qatari and non-Qatari Arab women were 9.8% and 6.1%, respectively and 7.6% and 16.7% in women with normal and abnormal cytology, respectively. HPV 81 was the most commonly found genotype in women with normal cytology (34.5%), whereas HPV 81, 16 and 59 in women with abnormal cytology (25.0% each). All the HPV DNA positive women were seronegative and HPV-IgG prevalence was higher in Qatari women than in non-Qatari Arab women. None of the studied factors had any significant association with HPV-DNA positivity or HPV-IgG seropositivity. The overall identified HPV DNA prevalence and HPV seroprevalence among Arab women in Qatar were on the low side compared to global levels.

Prevalence of IgG Antibodies against Human Papillomavirus (HPV) type 6, 11, 16, and 18 Virus-Like Particles in Women of Childbearing Age in Port Harcourt, Nigeria

Most HPV prevalence studies have been carried out in high-resource countries with few studies focused on low-resource regions where highest HPV prevalence in the world occurs. This study reports on prevalence of IgG antibodies against HPVs among women of childbearing age in Port Harcourt, Nigeria. One hundred and eighty-two consented women (age-range 19-45 years) were consecutively recruited. Demographic/behavioral data and 5 mL blood samples were collected from each woman. Plasma of each sample was assayed for HPV-6/11/16/18 virus-like particles using a HPV IgG ELISA kit. The overall anti-HPV prevalence was 4.9% while 7.7% with itching/wound in the private part tested positive. Most (88.9%) of the seropositive women were sexually active. Group-specific seropositivity was low (0.0-10.0%). It also showed that all the 9(100.0%) who tested positive to the HPV responded "yes" to no information on the source of HPV information. Being younger, married, high educational level, religion, and lack of information on HPV were the main correlates of HPV positivity among these women. None was vaccinated and would have been naturally exposed to at least one of HPV-6/11/16/18. With 4.9% seropositivity and lack of information regarding HPV among these women, this study recommends a statewide enlightenment campaign and vaccination.

Epidemiology of HPV genotypes in Uganda and the role of the current preventive vaccines: A systematic review

BACKGROUND

Limited data are available on the distribution of human papillomavirus (HPV) genotypes in the general population and in invasive cervical cancer (ICC) in Uganda. Yet, with the advent of preventive HPV vaccines that target HPV 16 and 18 responsible for causing about 70% of ICC cases in the world, such information is crucial to predict how vaccination and HPV-based screening will influence prevention of ICC.

METHODS

To review the distribution of HPV infection and prevalent genotypes, electronic databases (e.g. PubMed/MEDLINE and HINARI) were searched for peer reviewed English articles on HPV infection up to November 30, 2010. Eligible studies were selected according to the following criteria: DNA-confirmed cervical or male genital HPV prevalence and genotypes, HPV incidence estimates and HPV seroprevalence among participants.

RESULTS

Twenty studies were included in the review. Among HIV negative adult women, the prevalence of HR-HPV infections ranged from 10.2% -40.0% compared to 37.0% -100.0% among HIV positive women. Among HIV positive young women aged below 25 years, the prevalence of HR-HPV genotypes ranged from 41.6% -75.0% compared to 23.7% -67.1% among HIV negative women. Multiple infections with non vaccine HR-HPV genotypes were frequent in both HIV positive and HIV negative women. The main risk factors for prevalent HPV infections were age, lifetime number of sexual partners and HIV infection. Incident infections with HR-HPV genotypes were more frequent among adult HIV positive than HIV negative women estimated at 17.3 and 7.0 per 100 person-years, respectively. Similarly, incident HR-HPV among young women aged below 25 years were more frequent among HIV positive (40.0 per 100 person-years) than HIV negative women (20.3 per 100 person-years) women. The main risk factor for incident infection was HIV infection. HPV 16 and 18 were the most common genotypes in ICC with HPV 16/18 contributing up to 73.5% of cases with single infections.Among uncircumcised adult HIV positive males, HR-HPV prevalence ranged from 55.3% -76.6% compared to 38.6% -47.6% in HIV negative males. Incident and multiple HR-HPV infections were frequent in HIV positive males. Being uncircumcised was the main risk factor for both prevalent and incident HPV infection.

CONCLUSION

Infections with HR-HPV genotypes were very common particularly among HIV positive individuals and young women irrespective of HIV status. Given the high prevalence of HIV infection, HPV-associated conditions represent a major public health burden in Uganda. However, although the most common HPV genotypes in ICC cases in Uganda were those targeted by current preventive vaccines, there were a large number of individuals infected with other HR-HPV genotypes. Technology allowing, these other HR-HPV types should be considered in the development of the next generation of vaccines.

Seroprevalence of antibodies against human papillomavirus (HPV) types 16 and 18 in four continents: the International Agency for Research on Cancer HPV Prevalence Surveys

BACKGROUND

Few human papillomavirus (HPV) seroprevalence studies have been carried out in women from low-resource countries.

METHODS

Seroprevalence of antibodies against HPV16 and HPV18 was assessed in 7,074 women ≥15 years of age (median 44 years) from eight world areas. Serum antibodies against HPV16 and HPV18 were tested for using enzyme-linked immunosorbent assay. HPV DNA was assessed using a general primer GP5+/6+-mediated PCR.

RESULTS

HPV16 and HPV18 seroprevalence both ranged from <1% (Hanoi, Vietnam) to >or=25% (Nigeria). Of women who were HPV16 or HPV18 DNA-positive, seropositivity for the same type was 39.8% and 23.2%, respectively. Seropositivity for either type was directly associated with markers of sexual behavior. HPV16 and/or 18 (HPV16/18)-seropositive women had an increased risk of having cytologic abnormalities only if they were also HPV DNA-positive. A high international correlation was found between HPV16/18 seroprevalence and overall HPV DNA prevalence (r = 0.81; P = 0.022). However, HPV16/18 seroprevalence was substantially higher than the corresponding DNA prevalence in all study areas (although to different extents) and, contrary to DNA, tended to increase from young to middle age, and then decline or remain fairly constant. In all study areas, the vast majority of the information on the burden of exposure to HPV16/18 derived from serology.

CONCLUSIONS

The correlation between HPV DNA and HPV serology was not very good at an individual woman level, but high at a population level.

IMPACT

HPV serology is a poor marker of current infection or related lesions, but it can contribute, together with DNA, in evaluating the variations in the burden of HPV infection worldwide.

Epidemiology and natural history of penile cancer

An extensive literature search was performed using the key words squamous cell carcinoma of the penis, phimosis, circumcision, chronic balanitis, cigarette smoking, genital warts and human papillomavirus (HPV) infection. All selected studies were classified according to the level of evidence (LE). The final grades of recommendation were assigned after discussion by the full panel of the International Consultation on Penile Cancer in November 2008. The factors positively associated with invasive penile cancers include the presence of phimosis (LE 3a), tobacco smoking (LE 3a-4), chewing tobacco (LE 3a), injury to the penis (LE 3a), balanitis (LE 3a), genital warts (LE 3a), and high-risk HPV infection (LE 3a-4).

Penile cancer--prevention and premalignant conditions

OBJECTIVES

Relatively little evidence is available in the published studies on the prevention of penile cancer and premalignant conditions of the penis. The present review examined the current evidence available in preventing penile cancer and pathologic subtypes of premalignant conditions and their treatment. The recommendations made in the present review formulate the basis of the recent 2009 International Consultation on Urologic Disease Consensus Publishing Group.

METHODS

The association of human papillomavirus subtypes and penile cancer is well-established, although the etiology, natural history, and treatment of premalignant lesions have mainly been reported in retrospective case series with short-term follow-up. The exact pathologic role of chronic inflammatory conditions, such as balanitis xerotica obliterans in the etiology of penile cancer remains largely unknown.

RESULTS

Some of the potential strategies for the prevention of penile cancer could include circumcision, reducing the risk of transmission of penile human papillomavirus infection with male vaccination, early treatment of phimosis, smoking cessation, and hygienic measures. Implementing some of these measures would require extensive cost/benefit analysis, with significant changes in the global health policy.

CONCLUSIONS

Owing to the current levels of evidence from published studies, firm guidelines cannot be formulated for the treatment of premalignant conditions, although preventative measures, such as reducing human papillomavirus transmission, could become strategic health targets.

Changing cancer incidence in Kampala, Uganda, 1991-2006

Incidence rates of different cancers have been calculated for the population of Kyadondo County (Kampala, Uganda) for a 16-year period (1991-2006). This period coincides with continuing social and lifestyle changes and the peak and subsequent wane of the epidemic of HIV-AIDS. There has been an overall increase in the risk of cancer during the period in both sexes, with the incidence rates of cancers of the breast and prostate showing particularly marked increases (4.5% annually). Prostate cancer is now the most common cancer in men. The incidence of cancer of the esophagus, formerly the most common cancer in men and second in frequency in women, has remained relatively constant, whereas the incidence of cancer of the cervix, the most common malignancy in women, continues to increase. Since the early 1990s the incidence of Kaposi sarcoma (KS) in men has declined, and while remaining relatively constant in women, it has been diagnosed at progressively later ages. The rates of pediatric KS have declined by about 1/3rd. The incidence of squamous cell cancers of the conjunctiva has also declined since the mid 1990s. Cancer control in Uganda, as elsewhere in sub-Saharan Africa, involves meeting the challenge of emerging cancers associated with westernization of lifestyles (large bowel, breast and prostate); although the incidence of cancers associated with poverty and infection (liver, cervix, esophagus) shows little decline, the residual burden of the AIDS-associated cancers remains a major burden.

Human papillomavirus prevalence and type distribution in penile carcinoma

BACKGROUND

Penile carcinoma is an uncommon and potentially mutilating disease with a heterogeneous aetiology. Several risk factors have been established for its development. Human papillomavirus (HPV) infection seems to play an important role in the development of a subset of these carcinomas and its presence is thought to be related to the histological type. HPV prevalence in penile tumours is reported to be associated to a variety of morphological changes. Its determination will provide a better estimate for HPV related cancer burden and its preventable fraction.

METHODS

A systematic and comprehensive literature review of the major penile cancer studies published from 1986 until June 2008 evaluating the HPV prevalence among the different histological types was carried out.

RESULTS

31 studies including 1466 penile carcinomas were reviewed. Global HPV prevalence was 46.9%. Relative contribution was: HPV-16 (60.23%), HPV-18 (13.35%), HPV-6/11 (8.13%), HPV-31 (1.16%), HPV-45 (1.16%), HPV-33 (0.97%), HPV-52 (0.58%), other types (2.47%). Assessment of multiple infections contribution is limited due to study design. Basaloid and warty squamous cell carcinomas were the most frequent HPV-related histological types, but keratinising and non-keratinising subtypes also showed prevalence rates of around 50%.

CONCLUSIONS

About half of the penile tumours were associated with HPV 16-18 with little presence of other genotypes. Research on the mechanisms behind penile carcinogenesis is warranted. Available HPV vaccines are likely to be effective in penile tumours.

A case-control study of cancer of the uterine cervix in Uganda

As part of an epidemiological study of cancer in Uganda, we investigated social, sexual and reproductive factors in relation to the risk of cancer of the uterine cervix. Patients with all cancer types or with benign tumours were recruited from hospitals in Kampala, Uganda, interviewed about various demographic and lifestyle factors and tested for antibodies against the human immunodeficiency virus-1 (HIV). The case-control study reported here involves 702 HIV-seronegative women, 343 of whom were diagnosed with cancer of the uterine cervix. Key findings were that the risk of cervical cancer increased linearly with the number of pregnancies [chi2(1)=44.7; P<0.0001]; a woman reporting having had 10 or more children had a roughly seven-fold increase in risk of the tumour as compared with women reporting fewer than four pregnancies (odds ratio=7.1; 95% confidence interval 3.8-13.2). The risk also varied inversely with age at first reported sexual intercourse [chi2(1)=8.4; P=0.004], perhaps reflecting an earlier age of infection with human papillomavirus, the main causal agent. These results are in line with those reported from studies in other countries.

Demographic and pathologic differences in the incidence of invasive penile cancer in the United States, 1995-2003

OBJECTIVE

Penile cancer is an uncommon malignancy, so few descriptive or analytic studies have been reported in the literature. The objective of this analysis was to describe the distribution of penile cancer in the United States by demographic, pathologic, and clinical features.

METHODS

Penile cancer among 6,539 men was identified through 29 population-based registries in the United States during the period 1995-2003. These registries were estimated to represent 68% of the U.S. population. Age-adjusted incidence rates were calculated per million population using counts derived from the 2000 U.S. census. A subset of nine registries was used to examine time trends in penile cancer between 1973 and 2003.

RESULTS

Squamous cell carcinomas were the most common histologic type of penile cancer, representing 93% of all malignancies. Hispanic men had the highest age-adjusted incidence rates per million for penile cancer (6.58 per million), followed by Blacks (4.02 per million), Whites (3.90 per million), American Indians (2.81 per million), and Asian-Pacific Islanders (2.40 per million). The highest rates of penile cancer were found among Hispanic men (46.9 per million) and Black men (36.2 per million) of ages >/=85 years. Penile malignancy was rare among males under age 20 years. Time trend analysis supported a significant decrease in the incidence of penile cancer for Blacks (annual percent change, -1.9%) and Whites (annual percent change, -1.2%). The majority (61%) of penile cancers were diagnosed at a localized stage among all racial and ethnic groups, although Hispanic and Black men tended to be diagnosed at more advanced stages than Whites. No racial or ethnic differences in tumor grade were identified. The incidence of penile cancer was highest in the South (4.42 per million) and lowest in the West (3.28 per million) of the United States. The highest age-adjusted incidence rate was found among Black men in the South (4.77 per million) and the lowest rate among Asian-Pacific Islanders in the West (1.84 per million).

CONCLUSIONS

This analysis showed significant racial/ethnic and regional variation in the incidence of penile cancer. The high rate of penile cancer among Hispanic and Southern Black men suggests differences in risk factors for this malignancy, such as circumcision, hygiene, or human papillomavirus exposure.

Cervical human papillomavirus (HPV) infection and HPV type 16 antibodies in South African women

There is a high incidence of cervical cancer in South African women. No large studies to assess human papillomavirus virus (HPV) infection or HPV type 16 (HPV-16) exposure have occurred in the region, a requirement for policy making with regards to HPV screening and the introduction of vaccines. Control women (n = 1,003) enrolled in a case control study of hormonal contraceptives and cervical cancer were tested for 27 cervical HPV types by reverse line blot analysis. The seroprevalence of HPV-16 immunoglobulin G (IgG) and IgA antibodies was assessed by a virus-like particle-based enzyme-linked immunoassay of 908 and 904 control women, respectively, and of 474 women with cervical cancer. The cervical HPV prevalence was 26.1%. The HPV-16 IgG seroprevalence was 44.4% and the HPV-16 IgA seroprevalence was 28.7% in control women, and these levels were significantly higher (61.8% and 52.7%, respectively) for women with cervical cancer (odds ratio [OR], 2.1 and 2.8, respectively). The cervical HPV prevalence showed an association with cervical disease, and the HPV-16 IgG prevalence decreased while the HPV-16 IgA prevalence increased with increasing age (P < 0.05). The prevalence of oncogenic HPV types (including HPV-16) decreased with age, whereas nononcogenic HPV types showed limited association with age. Multivariate analysis revealed cervical HPV infection to be associated with herpes simplex virus type 2 infection (OR, 1.7) and increasing years of education (OR, 1.9). HPV-16 IgG antibodies were inversely associated with current smoking status (OR, 0.6), and the presence of HPV-16 IgA antibodies was inversely associated with the use of alcohol (OR, 2.1) and inversely associated with the use of oral contraceptives (OR, 0.6). High levels of exposure to HPV, and particularly HPV-16, were evident in this population. The apparent increase of serum HPV-16 IgA with increasing age requires further investigation.

The role of high-risk HPV-DNA testing in the male sexual partners of women with HPV-induced lesions

OBJECTIVES

The objectives were to assess the prevalence of high-risk HPV in the male sexual partners of women with HPV-induced lesions, and correlate it with biopsies guided by peniscopy.

STUDY DESIGN

Fifty-four asymptomatic male sexual partners of women with low-grade squamous intra-epithelial lesions (LSIL) associated with high-risk HPV were examined between April 2003 and June 2005. The DNA-HPV was tested using a second-generation hybrid capture technique in scraped penile samples. Peniscopy identified acetowhite lesions leading to biopsy.

RESULTS

High-risk HPV was present in 25.9% (14 out of 54) of the cases. Peniscopy led to 13 biopsies (24.07%), which resulted in two cases of condyloma, two cases of intra-epithelial neoplasia (PIN) I, one case of PIN II, and eight cases of normal tissue. The high-risk HPV test demonstrated 80% sensitivity, 100% specificity, 100% positive predictive value, and 88.9% negative predictive value for the identification of penile lesions. There was a greater chance of finding HPV lesions in the biopsy in the positive cases of high-risk HPV with abnormal peniscopy (p=0.007); OR=51 (CI 1.7-1527.1).

CONCLUSION

Among asymptomatic male sexual partners of women with low-grade intra-epithelial squamous lesions, those infected by high-risk HPV have a higher chance of having abnormal penile tissue compared with male partners without that infection.

Helicobacter pylori and cancer among adults in Uganda

Data from Africa on infection with Helicobacter pylori (H. pylori) are sparse. Therefore, as part of an epidemiological study of cancer in Uganda, we investigated the prevalence and determinants of antibodies against H. pylori among 854 people with different cancer types and benign tumours. Patients were recruited from hospitals in Kampala, Uganda, interviewed about various demographic and lifestyle factors and tested for antibodies against H. pylori. In all patients combined, excluding those with stomach cancer (which has been associated with H. pylori infection), the prevalence of antibodies was 87% (723/833) overall, but declined with increasing age (p = 0.02) and was lower among people who were HIV seropositive compared to seronegative (p < 0.001). Otherwise, there were few consistent epidemiological associations. Among those with stomach cancer, 18/21 (86%) had anti-H. pylori antibodies (odds ratio 0.8, 95% confidence intervals 0.2-2.9, p = 0.7; estimated using all other patients as controls, with adjustment for age, sex and HIV serostatus). No other cancer site or type was significantly associated with anti-H. pylori antibodies. The prevalence of H. pylori reported here is broadly in accord with results from other developing countries, although the determinants of infection and its' role in the aetiology of gastric cancer in Uganda remain unclear.