Risk factors for Kaposi's sarcoma in HIV-positive subjects in Uganda

Kaposi sarcoma-associated herpesvirus, HIV-1 and Kaposi sarcoma risk in black South Africans diagnosed with cancer during antiretroviral treatment rollout

Kaposi sarcoma-associated herpesvirus (KSHV) causes Kaposi sarcoma (KS). The risk of KS is amplified in HIV-immunosuppressed individuals and antiretroviral therapy (ART) reduces KS incidence. Reliable data on the relationship between these factors are lacking in Africa. We used questionnaires and serum from 7886 black South Africans (18-74 years) with incident cancer, recruited between 1995 and 2016. ART rollout started in 2004. We measured associations between KS, HIV-1 and KSHV before and after ART rollout. We measured seropositivity to HIV-1, KSHV latency-associated nuclear antigen (LANA) and glycoprotein (K8.1) and calculated case-control-adjusted odds ratios (ORadj ) and 95% confidence intervals (CI) in relation to KS and KSHV infection, before (1995-2004), early (2005-2009) and late (2010-2016) ART rollout periods. KSHV seropositivity among 1237 KS cases was 98%. Among 6649 controls, KSHV seropositivity was higher in males (ORadj  = 1.4 [95%CI 1.23-1.52]), in persons with HIV, (ORadj  = 4.2 [95%CI 3.74-4.73]) and lower in high school leavers (ORadj  = 0.7 [95%CI 0.59-0.83]). KSHV seropositivity declined over the three ART rollout periods (37%, 28% and 28%, Ptrend  < .001) coinciding with increases in high school leavers over the same periods (46%, 58% and 67%, Ptrend  < .001). HIV-1 seroprevalence increased from 10% in the pre-ART period to 22% in the late ART period (Ptrend  < .001). Compared to HIV-1 and KSHV seronegatives, KSHV seropositives yielded an OR for KS of 26 (95%CI 11-62) in HIV-1 seronegative participants and an OR of 2501 (95%CI 1083-5776) in HIV-1 seropositive participants. HIV-1 increases the risk of KS in those infected with KSHV by 100-fold. Declines in KSHV seroprevalence coincide with ART rollout and with improvements in educational standards and general hygiene.

Lifestyle factors associated with sex differences in Kaposi sarcoma incidence among adult black South Africans: A case-control study

Kaposi Sarcoma (KS) is endemic in several countries in Southern and Eastern Africa, relatively rare worldwide but a leading cancer among people living with HIV. KS has always been more common in adult males than females. We assessed the prevalence of known cancer modifying factors (parity, hormonal contraceptive use in females, sex-partners, smoking and alcohol consumption in both sexes), and their relationship to KS, and whether any of these could account for the unequal KS sex ratios. We calculated logistic regression case-control adjusted odds ratios (OR_adj), and 95% confidence intervals (95%CI), between KS and each of the modifying factors, using appropriate comparison controls. Controls were cancer types that had no known relationship to exposures of interest (infection or alcohol or smoking or contraceptive use). The majority of the 1275 KS cases were HIV positive (97%), vs. 15.7% in 10,309 controls. The risk of KS among those with HIV was high in males (OR_adj=116.70;95%CI=71.35-190.88) and females (OR_adj=93.91;95%CI=54.22-162.40). Among controls, the prevalence of smoking and alcohol consumption was five and three times higher in males vs. females. We found a positive association between KS and heavy vs. non-drinking (OR_adj=1.31;95%CI=1.03-1.67), and in current heavy vs. never smokers (OR_adj=1.82;95%CI=1.07-3.10). These associations remained positive for alcohol consumption (but with wider CIs) after stratification by sex, and restriction to HIV positive participants. We found no evidence of interactions of smoking and alcohol by sex. Smoking and alcohol consumption may provide a possible explanation for the KS sex differences, given both exposures are more common in men, but confounding and bias cannot be fully ruled out. The role smoking and alcohol play in relation to viral loads of HIV/KSHV, differences in immunological responses or other genetic differences between males and females warrant further studies.

Mapping evidence on the risk factors associated with pediatric cancers in sub-Saharan Africa: a scoping review

BACKGROUND

The rarity and heterogeneity of pediatric cancers make it difficult to assess risk factors associated with the development of cancer in this group. This also determines the quantity and quality of evidence for etiological factors linked to pediatric cancers. Evidence on the risk factors associated with pediatric cancers is scarce; however, it has been accumulating slowly over the years. As the disease burden shifts from communicable to non-communicable diseases, most of these low- to middle-income countries (LMICs) find themselves overburdened with changing health care priorities and needs. In sub-Saharan Africa, it is of major importance to pay particular attention to risk factors associated with pediatric cancer.

OBJECTIVE

To map evidence on risk factors associated with pediatric cancers in sub-Saharan Africa (SSA).

METHODS

This review was guided by Arksey and O'Malley's framework for conducting scoping reviews. Four electronic databases were searched in December 2018, and another manual search was conducted in February 2022 to include newly published eligible articles. The databases searched included PubMed and Health Source: Nursing/Academic Edition. We also searched articles from an academic search engine, Google scholar. This review included articles reporting the relevant outcomes of this study and articles reporting cancers in children in the 0-15 years age range. This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews (PRISMA-ScR): checklist and explanation.

RESULTS

We retrieved 7391 articles from the initial database. The final number of studies that were included for data extraction was 15. Evidence from the retrieved studies suggests that most childhood cancers in the SSA region are infection-induced. The type of cancer mostly reported is Burkitt Lymphoma and is diagnosed mostly in the tropical region of SSA. The type of risk factors was divided into three types: infection-induced, genetic, and demographic risk factors. Overall, based on the articles retrieved, there was limited evidence on the risk factors associated with pediatric cancers in SSA.

CONCLUSION

The limited evidence on the risk factors coupled with the lack of evidence on the true burden of these malignancies in the SSA hampers efforts to set priorities for childhood cancer control. Formulation of effective preventative (where possible) measures and treatment regimens will need proper assessment of risk factors.

Prevalence of Kaposi's sarcoma-associated herpesvirus and transfusion-transmissible infections in Tanzanian blood donors

OBJECTIVE

Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent for Kaposi's sarcoma (KS), one of the most common cancers in Tanzania. We have investigated KSHV prevalence and factors associated with KSHV infection in Tanzania.

METHODS

This is a cross-sectional study of voluntary blood-donors from Dar es Salaam, Tanzania. Plasma was screened for KSHV, HIV-1, HBV, HCV and Treponema pallidum (syphilis). Associations between KSHV sero-status and risk factors were analyzed. Odds ratios (OR) and 95% confidence intervals (CI) are reported to evaluate risk factors of KSHV infection. All tests were 2-tailed, and P-values <0.05 were considered statistically significant.

RESULTS

The overall KSHV seroprevalence was 56.9%. Significantly increased risk of KSHV infection was detected in persons from the Lake and Central Zones (OR=6.4, 95% CI=1.6-25.3, P=0.008 and OR=5.7, 95% CI=1.0-32.5, P=0.048 respectively). A trend toward increased risk of KSHV infection with HIV-1 co-infection was not significant (OR=2.8, 95% CI=1.0-8.0, P=0.06). Seroreactivity to T. pallidum was surprisingly high (14.9%).

CONCLUSION

The prevalence of KSHV infection and syphilis was high among Tanzanian blood-donors. The most common transfusion-transmissible infections did not associate with KSHV infection. Regions of focal KSHV infection need further investigation for underappreciated risk factors.

Selected genes of Human herpesvirus-8 associated Kaposi's sarcoma among patients with Human Immunodeficiency Virus-1 and Acquired Immunodeficiency Disease Syndrome

INTRODUCTION

Kaposi's sarcoma (KS) is a kind of cancer that causes flat or raised lesions containing Human herpes virus 8 (HHV8). The KS lesions are common among immunosuppressed HIV patients. Highly Active Antiretroviral (HHART) treats and prevents the development of KS. The objective of this study was to determine the presence of K1 and K15 (predominant alleles) genes in Kaposi's sarcoma-associated herpes virus (KSHV) among immunosuppressed patients due to HIV-1.

METHODS

This was a cross-sectional descriptive study where consecutive sampling technique was adopted to pick archived tissue blocks from the Thematic Unit of Anatomic Pathology, Department of Human Pathology, College of Health Sciences, University of Nairobi and Department of Laboratory Medicine, Histology Section, Kenyatta National Hospital.

RESULTS

Upon staining 81 tissue blocks with H & E, 84% (68/81) were diagnosed as KS and 16% (13/81) as KS-like. The K1 and K15 (P) genes were both detected at 88.9% (72/81) in the tissue blocks, with 95.8% (69/72) detection from KS and 4.2% (3/72) from the KS-like.

CONCLUSION

The K1 and K15 (P) genes of KSHV were present among the immunosuppressed patients with Human Immunodeficiency Virus (HIV)-1. It is important to carry out K1 and K15 (P) genes detection on tissues that are diagnosed as KS or KS-like by histology technique.

Kaposi's sarcoma in persons living with HIV/AIDS: a case series in a tertiary referral hospital

BACKGROUND

Kaposi's sarcoma (KS) is a rare neoplasm with indolent progression. Since 1981, the Kaposi's sarcoma epidemic has increased as co-infection with HIV.

OBJECTIVES

The study aimed to identify the clinical and demographic characteristics and therapeutic approaches in HIV/AIDS patients in a regional referral hospital.

METHODS

We analyzed the medical records of 51 patients with histopathological diagnosis of Kaposi's sarcoma hospitalized at Hospital Universitário João de Barros Barreto (HUJBB) from 2004 to 2015.

RESULTS

The study sample consisted of individuals 15 to 44 years of age (80.4%), male (80.4%), single (86.3%), and residing in Greater Metropolitan Belém, Pará State, Brazil. The primary skin lesions identified at diagnosis were violaceous macules (45%) and violaceous papules (25%). Visceral involvement was seen in 62.7%, mainly affecting the stomach (75%). The most frequent treatment regimen was 2 NRTI + NNRTI, and 60.8% were referred to chemotherapy.

STUDY LIMITATIONS

We assumed that more patients had been admitted to hospital without histopathological confirmation or with pathology reports from other services, so that the current study probably underestimated the number of KS cases.

CONCLUSION

Although the cutaneous manifestations in most of these patients were non-exuberant skin lesions like macules and papules, many already showed visceral involvement. Meticulous screening of these patients is thus mandatory, even if the skin lesions are subtle and localized.

Beral et al's 1990 paper on Kaposi's sarcoma among persons with AIDS: demonstrating the power of descriptive epidemiology

Here we discuss the impact of Beral et al's 1990 paper "Kaposi's sarcoma among persons with AIDS: a sexually transmitted infection?" Not only did this paper galvanise research into the underlying infectious cause of Kaposi's sarcoma, it also demonstrated the power of observational epidemiology in pointing the way towards major discoveries.

Viral infections associated with oral cancers and diseases in the context of HIV: a workshop report

Human herpesviruses (HHVs) and human papillomavirus (HPV) are common in the general population and, in immunocompetent people, are mostly carried asymptomatically. However, once an individual becomes immunocompromised by age, illness or HIV infection these dormant viruses can manifest and produce disease. In HIV-positive patients, there is an increased risk of disease caused by HHVs and HPV infections and cancers caused by the oncoviruses Epstein-Barr Virus, HHV-8 and HPV. This workshop examined four questions regarding the viruses associated with oral cancers and disease in the HIV-positive and -negative populations, the immune response, and biomarkers useful for accurate diagnostics of these infections and their sequalae. Each presenter identified a number of key areas where further research is required.

Human herpesvirus 8 seroconversion in a population-based cohort of men in Tobago

Human herpesvirus 8 (HHV-8) is the causal agent of Kaposi's sarcoma (KS). In Tobago, KS is not common; however, HHV-8 seropositivity has been reported to be 39.9% in men with prostate cancer compared to <22.9% in healthier women and men. To understand HHV-8 transmission, we examined HHV-8 seroconversion and seroreversion, and risk factors for these changes in Tobago men. Serum specimens from a sub-cohort of Tobago Prostate Survey men, aged 40-81 years (n = 381/442), were collected at baseline and a subsequent visit between 3 and 9 years and tested for HHV-8 seropositivity using an immunofluorescence assay for antibodies against HHV-8 lytic antigens. Poisson distribution was used to calculate HHV-8 seroconversion and seroreversion rates and their 95% confidence intervals. Differences in baseline characteristics between HHV-seroconverters versus persistent HHV-8 seronegative men and HHV-8 seroreverters versus HHV-8 seropositive men were examined. HHV-8 seropositivity was 12.3% (N = 381) at baseline, with HHV-8 seropositivity significantly higher in increasing age groups, 40-49 (4.0%) to 70-81 (37.5%) years (P-value trend <0.0001). HHV-8 seroconversion and seroreversion rates were 0.23 per 100 person-years (95% C.I., 0.06-0.58) and 2.42 per 100 person-years (95% C.I., 0.89-5.26), respectively. There were significantly more HHV-8 seroconverters who reported "ever smoked cigarettes of >6 months" at baseline compared to HHV-8 persistent seronegative men (P-value = 0.03). Baseline characteristics of HHV-8 seroreverters did not differ from persistent seropositive men. Low HHV-8 seroconversion and seroreversion rates were found. Data suggest that HHV-8 transmission occurred at earlier ages, <40 years, in Tobago men.

Epidemiology and genetic variability of HHV-8/KSHV in Pygmy and Bantu populations in Cameroon

Background

Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8) is the causal agent of all forms of Kaposi sarcoma. Molecular epidemiology of the variable K1 region identified five major subtypes exhibiting a clear geographical clustering. The present study is designed to gain new insights into the KSHV epidemiology and genetic diversity in Cameroon.

Methodology/Principal Findings

Bantu and Pygmy populations from remote rural villages were studied. Antibodies directed against latent nuclear antigens (LANA) were detected by indirect immunofluorescence using BC3 cells. Peripheral blood cell DNAs were subjected to a nested PCR amplifying a 737 bp K1 gene fragment. Consensus sequences were phylogenetically analyzed. We studied 2,063 persons (967 females, 1,096 males, mean age 39 years), either Bantus (1,276) or Pygmies (787). The Bantu group was older (42 versus 35 years: P<10⁻⁴). KSHV anti-LANA seroprevalence was of 37.2% (768/2063), with a significant increase with age (P<10⁻⁴) but no difference according to sex. Seroprevalence, as well as the anti-LANA antibodies titres, were higher in Bantus (43.2%) than in Pygmies (27.6%) (P<10⁻⁴), independently of age. We generated 29 K1 sequences, comprising 24 Bantus and five Pygmies. These sequences belonged to A5 (24 cases) or B (five cases) subtypes. They exhibited neither geographical nor ethnic aggregation. A5 strains showed a wide genetic diversity while the B strains were more homogenous and belonged to the B1 subgroup.

Conclusion

These data demonstrate high KSHV seroprevalence in the two major populations living in Southern and Eastern Cameroon with presence of mostly genetically diverse A5 but also B K1 subtypes.

Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8) is the causal agent of one of the most frequent skin tumors found endemically or epidemically associated to HIV in Central and Eastern Africa. This highly variable virus tends to cluster geographically according to specific major subtypes. Its prevalence is high in that area and increases with age. Despite its association to all forms of Kaposi sarcoma and high prevalence described in some low income populations in Cameroon, KSHV arouses limited interest, and only few focused previous studies have looked into prevalence and modes of transmission, especially in families. Extended molecular epidemiology is unknown both in healthy individuals and in Kaposi patients, which led to looking for new insights among Bantu and Pygmy populations from rural villages in three regions of Cameroon sharing a quite similar living environment but yet genetically, socially, and culturally different. The present study is designed to describe variations of molecular subtypes in each of these population groups regarding their geography in rural areas of southern, central, and eastern Cameroon.

Risk factors for Kaposi's sarcoma among HIV-positive individuals in a case control study in Cameroon

BACKGROUND

Individuals co-infected with Kaposi's sarcoma herpesvirus (KSHV) and Human Immunodeficiency Virus (HIV) are at greatly increased risk of developing Kaposi's sarcoma (KS). The objective of the current analysis is to identify risk cofactors for KS among HIV-positive individuals.

METHODS

We conducted a case-control study of KS in Cameroon on 161 HIV-positive and 14 HIV-negative cases and 680 HIV-positive and 322 HIV-negative controls. Participants answered a physician-administered questionnaire and provided blood and saliva specimens. Antibodies against KSHV lytic, K8.1, and latent, ORF73, antigens were measured by ELISA to determine KSHV serostatus. Conditional logistic regression was performed to determine multivariate odds ratios (OR) and 95% confidence intervals (CI) for risk factors associated with KS among HIV-positive cases and controls.

RESULTS

Overall, 98% (158) of HIV-positive cases, 100% (14) of HIV-negative cases, 81% (550) of HIV-positive controls, and 80% (257) of HIV-negative controls were KSHV seropositive. Risk factors for KS among HIV-positive individuals included KSHV seropositivity (OR=9.6; 95% CI 2.9, 31.5), non-use of a mosquito bed net (OR 1.9; 95% CI 1.2, 2.9), minority ethnicity (OR=3.1; 95% CI 1.1, 9.3), treatment from a traditional healer (OR=2.3; 95% CI 1.5, 3.7), history of transfusion (OR=2.4; 95% CI 1.5, 3.9), and family history of cancer (OR=1.9; 95% CI 1.1, 3.1).

CONCLUSION

KSHV seroprevalence of ≥80% indicates a high prevalence in the general population in Cameroon. Among HIV-positive individuals, the strong association of KS with non-use of mosquito nets and treatment from traditional healers are compelling findings, consistent with recently reported data from East Africa.

Parasite infection is associated with Kaposi's sarcoma associated herpesvirus (KSHV) in Ugandan women

Background

Immune modulation by parasites may influence susceptibility to bacteria and viruses. We examined the association between current parasite infections, HIV and syphilis (measured in blood or stool samples using standard methods) and antibodies against Kaposi's sarcoma herpesvirus (KSHV), measured by ELISA, in 1915 stored plasma samples from pregnant women in Entebbe, Uganda.

Results

Seroprevalence of KSHV was higher in women with malaria parasitaemia (73% vs 60% p = 0.01), hookworm (67% vs 56% p = 0.001) and Mansonella perstans (69% vs 59% p = 0.05); seroprevalence increased with increasing intensity of hookworm infection (p < 0.001[trend]). No associations were found for HIV, five other parasites or active syphilis. These effects were not explained by socioeconomic status or education.

Conclusions

Specific parasite infections are associated with presence of antibodies against KSHV, perhaps mediated via their effect on immune function.

Presentation and survival of patients with AIDS-related Kaposi's sarcoma in Jos, Nigeria

AIDS-related Kaposi's sarcoma (AIDS-KS) remains a significant cause of morbidity and mortality. We describe the pattern of presentation and survival in Jos, Nigeria. We identified 48 HIV-positive patients with AIDS-KS and matched them for age and sex with an equal number of HIV-positive patients without AIDS-KS. We compared their clinical, immunological, virological characteristics and survival. They were similar in age and body mass index profile but patients with AIDS-KS had more tuberculosis co-infection (P, 0.02), lower median CD4 count (P, 0.003) and higher mortality (P, 0.002). Surprisingly, patients with AIDS-KS had lower levels of median viral load (29,347 copies/mL) compared with controls (80,533 copies/mL). We recommend specific AIDS-KS therapy in addition to highly active antiretroviral therapy in order to improve survival.

Access to and utilisation of health services for the poor in Uganda: a systematic review of available evidence

Inequalities in the burden of disease and access to health care is a prominent concern in Uganda and other sub-Saharan African countries. This is a systematic review of socio-economic differences in morbidity and access to health care in Uganda. It includes published studies from electronic databases and official reports from surveys done by government, bilateral and multilateral agencies and universities. The outcome measures studied were: the distribution of HIV/AIDS; maternal and child morbidity; and access to and utilisation of health services for people belonging to different socio-economic and vulnerability groups. Forty-eight of 678 identified studies met our inclusion criteria. Results indicate that the poor and vulnerable experience a greater burden of disease but have lower access to health services than the less poor. Barriers to access arise from both the service providers and the consumers. Distance to service points, perceived quality of care and availability of drugs are key determinants of utilisation. Other barriers are perceived lack of skilled staff in public facilities, late referrals, health worker attitude, costs of care and lack of knowledge. Longitudinal and controlled studies are needed to see if strategies to improve access to services reach the poor.

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.

HIV-associated Kaposi sarcoma: pathogenic mechanisms

Kaposi sarcoma (KS) is a multicentric angioproliferative disorder characterized by spindle cell proliferation, neo-angiogenesis, inflammation, and edema. Human herpesvirus (HHV)-8, a gamma-herpesvirus, is a critical factor, but is not alone sufficient for the initiation of KS. Other cofactors such as human immunodeficiency virus (HIV), host-derived cytokines, chemokines, and growth factors are required for the development of KS. Whether HIV-associated KS is a reactive hyperplastic inflammatory lesion or a true neoplasm is still controversial. It is likely that HIV-associated KS begins as a reactive disorder that in some cases progresses to a monoclonal, an oligoclonal, and a polyclonal neoplasm.

Diverse genotypes of Kaposi's sarcoma associated herpesvirus (KSHV) identified in infant blood infections in African childhood-KS and HIV/AIDS endemic region

Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8) has been associated with several neoplasias, including childhood endemic Kaposi's sarcoma (KS). It is possible that strain genotypes could contribute to the differences in regional presentation (mainly sub-Saharan Africa), childhood infection, lack of male sex bias, distinct disseminated forms and rapid fatality observed for childhood endemic KS. Early studies, at the advent of the HIV/AIDS epidemic, identified only the K1-A5 genotype in childhood KS biopsies as well as blood of a few HIV positive and negative febrile infants in Zambia, a highly endemic region. This current enlarged study analyses blood infections of 200 hospitalized infants (6-34 months age) with symptoms of fever as well as upper respiratory tract infection, diarrhoea, rash or rhinitis. KSHV and HIV viraemia and were prevalent in this group, 22% and 39%, respectively. Multiple markers at both variable ends of the genome (K1, K12, and K14.1/K15) were examined, showing diverse previously adult-linked genotypes (K1 A2, A5, B, C3, D, with K12 B1 and B2 plus K14.1/K15 P or M) detected in both HIV positive and negative infants, demonstrating little restriction on KSHV genotypes for infant/childhood transmission in a childhood endemic KS endemic region. This supports the interpretation that the acquisition of childhood KSHV infections and subsequent development of KS are due to additional co-factors.

BK virus and cancer in Uganda

As part of an epidemiological study of cancer in Uganda, we investigated the titre of antibodies against BK virus among 821 people with different cancer types and benign tumours. Among study participants, 790 were considered seropositive for anti-BK virus antibodies and all analyses were conducted on transformed data. The mean optical density (a measure of antibody titre) for all patients combined (including the 31 who were considered seronegative) was 1.03 (standard error 0.01), but was 5% higher in women than in men (P=0.05), and 8% higher among HIV seropositive than seronegative people (P=0.002). Otherwise, there were few consistent associations between anti-BK virus antibodies and any social and lifestyle factor investigated. Differences in the mean optical density for each cancer type were estimated using multivariate analysis of variance with adjustment for sex, age group and HIV serostatus, using all other patients as controls. The mean optical density was about 17% lower among those with oral cancer (optical density 0.86, standard error 0.06; P=0.01, based on 30 patients) and about 20% higher among those with prostate cancer (optical density 1.22, standard error 0.09; P=0.01, based on 11 cases) than among all other patients combined. The number of cases of each cancer was too small to exclude the possibility of these findings arising by chance. No other cancer site or type was significantly associated with low, or with high anti-BK virus antibody titres.

HIV-associated Kaposi's sarcoma

Kaposi's sarcoma (KS) is a multifocal vascular tumor that occurs most commonly in patients who have immunosuppression caused by HIV. KS-associated herpes virus (human herpes virus 8, KSHV) has been identified as the causative agent. There are marked geographic differences in the prevalence of both KS and seropositivity to KSHV. The incidence of the tumor has shown a marked decline in first-world countries with the widespread use of effective antiretroviral therapy. The most effective anthracycline is pegylated liposomal doxorubicin; however, few developing countries, where KS prevalence is highest, can afford to use these agents.

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.

Role of environmental factors in the pathogenesis of classic and African-endemic Kaposi sarcoma

Kaposi sarcoma (KS) is a mesenchymal tumour associated with human herpesvirus-8 (HHV-8) infection. However, the incidence of HHV-8 infection is far higher than the prevalence of KS, suggesting that viral infection per se is not sufficient for the development of aggressive phenotype and that one or more additional cofactors are required. The great geographical variation in African-endemic and classic KS incidence points to a role for environmental factors in the etiology of Kaposi sarcoma. However, there are few unequivocably established environmental factors involved in KS pathogenesis. This review focuses on the environmental factors thought to be associated with KS, more particularly iron exposure and facilitation of transmission of HHV-8 infection by contact with blood-sucking arthropods.

Distribution of mosquito species in areas with high and low incidence of classic Kaposi's sarcoma and seroprevalence for HHV-8

The 'promoter-arthropod' hypothesis, which postulates that exposure to the bites of certain species of haematophagous arthropods is an environmental risk cofactor linked to human herpes virus 8 (HHV-8) and Kaposi's sarcoma, was investigated in the Po River valley, northern Italy. The presence and density of adult female mosquitoes (Diptera: Culicidae) was determined by CDC light trap catches in two adjacent districts, at variance with respect to Kaposi's sarcoma incidence and HHV-8 seroprevalence. A total of 3910 specimens belonging to 11 species was collected in 34 rural sites (six municipalities) representative of the two districts. Five of these species are considered to be possible 'promoters' because of the irritation their bites cause humans: Aedes vexans (Meigen) and Ae. caspius (Pallas) (87% of sampled promoters), Culex modestus Ficalbi, Culiseta annulata (Schrank) and Coquillettidia richiardii (Ficalbi). Six are probable 'non-promoters': Cx. pipiens s.l., Cx. martinii Medschid, Anopheles claviger (Meigen), An. maculipennis s.l., An. plumbeus Stephens and Uranotaenia unguiculata Edwards. The density of promoters by site was correlated with the incidence rates of Kaposi's sarcoma at the district level (Pearson's r = 0.33, P = 0.06) and at the municipal level (r = 0.50, P< 0.01). Similar correlations emerged for non-promoters (r = 0.48, P< 0.01 and r = 0.42, P = 0.01, respectively). The density of promoters was higher than that of non-promoters in sites with livestock (odds ratio, OR = 2.8, 95% CI 2.2-3.6) and in municipalities with Kaposi's sarcoma cases (OR = 2.5, 95% CI 1.7-3.5). The study provides additional evidence of the association between the density of some mosquito species and Kaposi's sarcoma.

Classic Kaposi sarcoma. Which KSHV-seropositive individuals are at risk?

BACKGROUND

Classic Kaposi sarcoma (CKS) is a relatively rare vascular disease primarily affecting human immunodeficiency virus (HIV)-uninfected elderly men. The infection with Kaposi sarcoma-associated herpesvirus (KSHV) is necessary for the establishment of Kaposi sarcoma (KS), although it is not sufficient. Thus, only a small fraction of KSHV-infected individuals develops KS. The cofactors that influence risk of KS among HIV-uninfected individuals are yet to be determined. The objective of the current study was to assess potential risk factors for CKS in the KSHV-infected Jewish population in Israel.

METHODS

A case-control study involved 35 CKS cases and 48 matched KSHV-infected controls. Lifestyle and medical history data from case patients and controls were compared by logistic regression analysis.

RESULTS

In a multivariate analysis, the authors identified an age-related small increased risk for CKS in subjects originating from Asia and Africa. The risk for CKS increased, although not significantly statistically, in subjects who reported alcohol consumption, diabetes mellitus, herpes simplex, and asthma. No relation was found with cigarette smoking, family size, number of lifetime sexual partners, or sexually transmitted disease.

CONCLUSIONS

A borderline increase in CKS risk among elderly subjects originating from Africa or Asia was identified. These results need to be further evaluated by larger studies. The authors believe that genetic and immunologic parameters may alter risk for CKS and, therefore, should also be investigated.

Molecular characterization of Kaposi's sarcoma associated herpesvirus (KSHV) from patients with AIDS-associated Kaposi's sarcoma in Sao Paulo, Brazil

BACKGROUND

Kaposi's sarcoma (KS) is caused by Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8), the eighth Herpesvirus found to infect humans. The molecular epidemiology of KSHV is related closely to ethnicity and geographical location of studied populations. There is little epidemiological and molecular information about KSHV strains circulating in Brazil.

OBJECTIVES

To characterize KSHV strains isolated from AIDS patients with Kaposi's sarcoma (AIDS-KS) in Sao Paulo, Brazil, and to examine associations between KSHV subtypes, ethnicity and HIV risk categories.

METHODS

AIDS-KS patients were recruited consecutively at the largest AIDS reference hospital in Sao Paulo. Fragments (420 bp) of the VR1 and VR2 regions of KSHV open reading frame (ORF) K1 were amplified by nested PCR and sequenced directly.

RESULTS

We analysed 37 samples from 33 patients, and found subtypes A-C in 48%, 21% and 30% of patients respectively, including two patients infected with subtype A5, a first report from Brazil. Sexual orientation was associated with subtype: 12/14 (86%) patients with subtype A were male homo/bisexual, compared with 3/8 (38%) among patients infected with subtype C (P = 0.05). A higher proportion of male patients with subtype C were of Caucasian origin (7/8 (87%)), compared with 7/16 (44%) among male patients with subtype A (P = 0.08).

CONCLUSIONS

This first detailed report of KSHV subtypes among AIDS-KS patients in Brazil reports the first isolation of KSHV subtype A5 in this country, and suggests KSHV strain transmission between different ethnic groups, and association of specific strains with sexual orientation.

Cancer survival in Kampala, Uganda

Epidemiological data on the occurrence of cancer in sub-Saharan Africa are sparse, and population-based cancer survival data are even more difficult to obtain due to various logistic difficulties. The population-based Cancer Registry of Kampala, Uganda, has followed up the vital status of all registered cancer patients with one of the 14 most common forms of cancer, who were diagnosed and registered between 1993 and 1997 in the study area. We report 5-year absolute and relative survival estimates of the Ugandan patients and compare them with those of black American patients diagnosed in the same years and included in the SEER Program of the United States. In general, the prognosis of cancer patients in Uganda was very poor. Differences in survival between the two patient populations were particularly dramatic for those cancer types for which early diagnosis and effective treatment is possible. For example, 5-year relative survival was as low as 8.3% for colorectal cancer and 17.7% for cervical cancer in Uganda, compared with 54.2 and 63.9%, respectively, for black American patients. The collection of good-quality follow-up data was possible in the African environment. The very poor prognosis of Ugandan patients is most likely explained by the lack of access to early diagnosis and treatment options in the country. On the policy level, the results underscore the importance of the consistent application of the national cancer control programme guidelines as outlined by the World Health Organization.

Water, socioeconomic factors, and human herpesvirus 8 infection in Ugandan children and their mothers

BACKGROUND

Human herpesvirus 8 (HHV-8) infection is common in sub-Saharan Africa, but its distribution is uneven. Transmission occurs during childhood within families by unclear routes.

METHODS

We evaluated 600 Ugandan children with sickle cell disease and their mothers for factors associated with HHV-8 seropositivity in a cross-sectional study. HHV-8 serostatus was determined using an HHV-8 K8.1 glycoprotein enzyme immunoassay. Odds ratios for seropositivity were estimated using logistic regression, and factor analysis was used to identify clustering among socioeconomic variables.

RESULTS

One hundred seventeen (21%) of 561 children and 166 (34%) of 485 mothers with definite HHV-8 serostatus were seropositive. For children, seropositivity was associated with age, mother's HHV-8 serostatus (especially for children aged 6 years or younger), lower maternal education level, mother's income, and low-status father's occupation (P < 0.05 for all). Using communal standpipe or using surface water sources were both associated with seropositivity (OR 2.70, 95% CI 0.80-9.06 and 4.02, 95% CI 1.18-13.7, respectively) as compared to using private tap water. These associations remained, albeit attenuated, after adjusting for maternal education and child's age (P = 0.08). In factor analysis, low scores on environmental and family factors, which captured household and parental characteristics, respectively, were positively associated with seropositivity (P(trend) < 0.05 for both). For mothers, HHV-8 seropositivity was significantly associated with water source and maternal income.

CONCLUSIONS

HHV-8 infection in Ugandan children was associated with lower socioeconomic status and using surface water. Households with limited access to water may have less hygienic practices that increase risk for HHV-8 infection.

Role of infectious diseases in human carcinogenesis

The burden of human infectious diseases remains a public health problem worldwide. At least 2 billion people are affected by viral infections, and a similar number by bacteria or helminths. The long-term effects of these maladies have raised particular concern since some infectious agents have been associated with chronic human diseases, especially cancer. It is estimated that 13-20% of the world cancer cases are associated with some virus, bacteria, or helminth, e.g., human papillomavirus, Helicobacter pylori, and Schistosoma haematobium that cause cervical, stomach, and urinary bladder cancer, respectively. Certain associations between infection and malignancy are strong and irrefutable; others are still speculative. This article reviews the infectious agents that have been associated with cancer and current knowledge about the mechanisms underlying these associations.

Human herpesvirus type 8 infection in an area of Northern Italy with high incidence of classical Kaposi's sarcoma

Previous studies have reported a large variation in the incidence of classical Kaposi's sarcoma across different Districts of the province of Mantua (Northern Italy). To assess whether such differences might be explained by different anti-HHV8 antibody prevalence, a serological study was conducted in 343 healthy elderly individuals resident in two adjacent Districts, at the highest and the lowest classical Kaposi's sarcoma incidence rate, respectively. Qualitative and quantitative determinations of IgG antibodies against both latent and lytic HHV-8 antigens were performed by indirect immunofluorescence assay. The assay's sensitivity was studied in 26 patients with classical Kaposi's sarcoma. Overall, anti-HHV8 antibodies were detected in 25 out of 26 patients (96%), confirming the high sensitivity of this assay. The prevalence of anti-HHV-8 antibodies was higher among individuals living in the District had a high incidence of classical Kaposi's sarcoma compared to those living in the District with low incidence (19.4% vs 9.8%, and 15.9% vs 8%; P<0.05, for latent and lytic antibodies, respectively). Anti-lytic antibody GMT was higher in people living in the District at high incidence rate compared to those of the other area (328.9 vs. 180.4; P<0.01). A higher prevalence of HHV-8 infection was found among persons living in municipalities surrounded by watercourses (OR 2.2, 95% CI: 1.10-4.32). In conclusion, variation in HHV-8 prevalence appears to explain differences in the incidence rates of classical Kaposi's sarcoma observed in different areas of the province.

Classic Kaposi's sarcoma in southern Sardinia, Italy

The first examination of classical Kaposi's sarcoma incidence in southern Sardinia (Italy) in 1998–2002 found the highest rate recorded in the island of 2.49 per 100 000 per year (standardised).

Viruses, chemicals and co-carcinogenesis

The etiology of cancers appears to be complex and multifactorial. Peyton Rous and others demonstrated the process of co-carcinogenesis by exposing rabbits to a virus and tars. Epidemiologists have proposed virus-chemical interactions to cause several cancers. For example, one might propose that the etiology of cervical cancer results from a complex interplay between oncogenic viruses and cervical tar exposures through tar-based vaginal douching, cigarette smoking, and/or long-term cooking over wood-burning stoves in poorly ventilated kitchens. Hepatocellular carcinoma may result from the joint effects of viruses and hepatotoxic chemical carcinogens. Kaposi's sarcoma might happen following reciprocal actions of human herpes virus-8 infection, immunosuppression, and chemical exposures, such as nitrite radicals and alumino-silicates. Use of Koch's postulates will not help one prove or disprove a multifactorial causation of disease; new criteria are needed. Delineating the web of causation may lead to additional strategies for prevention and treatment of several cancers.

Human papillomaviruses and cancer in Uganda

In a case-control study in Uganda, we examined associations between different cancer sites or types in relation to antibodies against human papillomaviruses (HPV)-16, -18 and -45. For each cancer site or type, the control group comprised all other cancers excluding those known, or thought to be associated with HPV infection (cancers of the uterine cervix, penis and eye). Among controls the seroprevalence of antibodies was 11% (68/616) against HPV-16, 5% (29/605) against HPV-18 and 6% (35/605) against HPV-45. Antibodies against HPV-16 were significantly associated with only two cancers: uterine cervix [prevalence of antibodies 27% (51/191); odds ratio (OR) 2.0, 95% confidence interval (CI) 1.2-3.1, P=0.01] and penis [prevalence of antibodies 27% (4/15); OR 6.4, 95% CI 1.7-24.3, P=0.01]. For both cancers, the risk increased with increasing anti-HPV-16 antibody titre (Ptrend=0.01 for each). No cancer site or type was significantly associated with antibodies against HPV-18 and -45.

Iron: a target for the management of Kaposi's sarcoma?

BACKGROUND

Kaposi's sarcoma (KS) is a mesenchymal tumour associated with human herpesvirus-8 infection. However, the incidence of human herpesvirus-8 infection is far higher than the prevalence of KS, suggesting that viral infection per se is not sufficient for the development of malignancy and that one or more additional cofactors are required.

DISCUSSION

Epidemiological data suggest that iron may be one of the cofactors involved in the pathogenesis of KS. Iron is a well-known carcinogen and may favour KS growth through several pathways. Based on the apoptotic and antiproliferative effect of iron chelation on KS cells, it is suggested that iron withdrawal strategies could be developed for the management of KS. Studies using potent iron chelators in suitable KS animal models are critical to evaluate whether iron deprivation may be a useful anti-KS strategy.

SUMMARY

It is suggested that iron may be one of non-viral co-factors involved of KS pathogenesis and that iron withdrawal strategies might interfere with tumour growth in patients with KS.

Risk factors for high anti-HHV-8 antibody titers (> or =1:51,200) in black, HIV-1 negative South African cancer patients: a case control study

BACKGROUND

Infection with human herpesvirus 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV), is the necessary causal agent in the development of Kaposi's sarcoma (KS). Infection with HIV-1, male gender and older age all increase risk for KS. However, the geographic distribution of HHV-8 and KS both prior to the HIV/AIDS epidemic and with HIV/AIDS suggest the presence of an additional co-factor in the development of KS.

METHODS

Between January 1994 and October 1997, we interviewed 2576 black in-patients with cancer in Johannesburg and Soweto, South Africa. Blood was tested for antibodies against HIV-1 and HHV-8 and the study was restricted to 2191 HIV-1 negative patients. Antibodies against the latent nuclear antigen of HHV-8 encoded by orf73 were detected with an indirect immunofluorescence assay. We examined the relationship between high anti-HHV-8 antibody titers (> or =1:51,200) and sociodemographic and behavioral factors using unconditional logistic regression models. Variables that were significant at p = 0.10 were included in multivariate analysis.

RESULTS

Of the 2191 HIV-1 negative patients who did not have Kaposi's sarcoma, 854 (39.0%) were positive for antibodies against HHV-8 according to the immunofluorescent assay. Among those seropositive for HHV-8, 530 (62.1%) had low titers (1:200), 227 (26.6%) had medium titers (1:51,200) and 97 (11.4%) had highest titers (1:204,800). Among the 2191 HIV-1 negative patients, the prevalence of high anti-HHV-8 antibody titers (> or =1:51,200) was independently associated with increasing age (p-trend = 0.04), having a marital status of separated or divorced (p = 0.003), using wood, coal or charcoal as fuel for cooking 20 years ago instead of electricity (p = 0.02) and consuming traditional maize beer more than one time a week (p = 0.02; p-trend for increasing consumption = 0.05) although this may be due to chance given the large number of predictors considered in this analysis.

CONCLUSIONS

Among HIV-negative subjects, patients with high anti-HHV-8 antibody titers are characterized by older age. Other associations that may be factors in the development of high anti-HHV-8 titers include exposure to poverty or a low socioeconomic status environment and consumption of traditional maize beer. The relationship between these variables and high anti-HHV-8 titers requires further, prospective study.

Infection with Kaposi's sarcoma-associated herpesvirus (KSHV) and human immunodeficiency virus (HIV) in relation to the risk and clinical presentation of Kaposi's sarcoma in Uganda

A case-control study from Uganda found that the risk of Kaposi's sarcoma increased with increasing titre of antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV) latent nuclear antigens, independently of HIV infection. Clinically, widespread Kaposi's sarcoma was more frequent among patients with HIV infection than in those without, but was not related to anti-KSHV antibody titres.

Kaposi's sarcoma in South Africa

Kaposi's sarcoma was endemic in South Africa even before the advent of the human immunodeficiency virus (HIV). Between 1988 and 1996, the incidence of Kaposi's sarcoma in South Africa has risen at least threefold and continues to increase as the HIV epidemic grows. Research from South Africa has shown that infection with human herpesvirus 8 (HHV8) is associated with Kaposi's sarcoma but not with any other major cancer site or type. In addition, the risk of Kaposi's sarcoma increases with increasing antibody titer to HHV8, but, for a given titer, the risk is greater in HIV-seropositive compared with HIV-seronegative individuals. The age- and sex-standardized seroprevalence of HHV8 in black South African hospital patients was found to be slightly more than 30%; the seroprevalence of HHV8 increased with age and was similar in men and in women. The modes of transmission of HHV8 are yet to be fully elucidated. Limited evidence exists for sexual transmission in black South African adults, but mother-to-child and person-to-person transmission in childhood is also likely. Furthermore, the seroprevalence of HHV8 decreases with increasing levels of education and is lower in whites than in blacks, suggesting that factors associated with poverty may be important determinants of transmission. Future research should focus on risk factors for Kaposi's sarcoma in HHV8-infected individuals, on determinants and mode of transmission of HHV8, and on the elucidation of the effect of primary HHV8 infection in adults and in children.

Epidemiology of AIDS-related malignancies an international perspective

Patients with HIV infection are at increased risk for developing Kaposi's sarcoma, non-Hodgkin's lymphoma, and several other cancers. The relative risks for the most common epithelial cancers in the general population--lung, breast, colon/rectum, stomach, liver, and prostate--are not increased substantially in people with AIDS, however. Accumulating data suggest that HIV-infected patients also are at increased risk for developing Hodgkin's lymphoma, cervical carcinoma in situ (CIS), other anogenital neoplasms (invasive cancer and CIS), leiomyosarcoma, and conjunctival squamous cell carcinoma. There is inconclusive evidence, however, with regard to HIV infection being associated with invasive cervical cancer, testicular seminoma, or hepatocellular carcinoma. Notably, other viral infections have been implicated in the etiology of many of these conditions. The introduction of highly active antiretroviral therapy (HAART) has decreased the incidence of AIDS-associated cancers in Western countries, but less than 1% of AIDS patients are receiving HAART in the HIV epicenter of sub-Saharan Africa. Further therapeutic advances that extend survival with HIV infection with varying reconstitution of immune competence may lead to additional alterations in cancer risk.

Causality or coincidence: may the slow disappearance of helminths be responsible for the imbalances in immune control mechanisms?

Intestinal infection continues to be a problem worldwide and helminths, which currently infect billions of individuals, are primary culprits. The major burden of disease falls on the populations of developing countries, given that over the last four to five decades helminth infections are disappearing in industrialized societies. In developing countries, a major source of immunomodulatory signals in post-natal life are parasites, particularly helminths, which, unlike most bacteria and viruses, selectively stimulate Th2 function. Helminths and their eggs are probably the most potent stimulators of mucosal Th2 responses. Responses elicited by worms can modulate immune reactions to other parasites, bacterial, viral infections and several unrelated diseases. Bacterial and protozoal infections may also protect against atopy and asthma, through the induction of the Th1 regulatory responses. Today, people in developed countries often live in ultra-hygienic environments, avoiding exposure to viruses, bacteria, ectoparasites and endoparasites, particularly helminths. Perhaps failure to acquire worms and experience mucosal Th2 conditioning predisposes to unrelated diseases. In contrast to this hypothesis it has also been suggested that Th2 responses can make the host more susceptible to other important diseases and to contribute to the spread of them.

Risk factors for Kaposi's sarcoma: a case-control study of HIV-seronegative people in Uganda

As part of a larger investigation of cancer in Uganda, we conducted a case-control study of Kaposi's sarcoma in human immunodeficiency virus-1 (HIV)-seronegative adults presenting at hospitals in Kampala. Cases comprised 117 HIV-seronegative patients with Kaposi's sarcoma and controls comprised 1,282 HIV-seronegative patients with a provisional diagnosis of cancer other than Kaposi's sarcoma. Study participants were interviewed about social and lifestyle factors, tested for HIV and, if there was sufficient sera, for antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV or human herpesvirus 8 [HHV8]), using an immunofluorescent assay. Independent effects of these factors were identified using unconditional logistic regression, after adjusting for age group (<30, 30-44, 45+) and sex. Antibody status for KSHV was available for 68% (80) of cases and for 45% (607) of controls. Among cases, 78% (91) were male and 57% (66) were over the age of 35. Cases were more likely than controls to be from tribal groups other than the Baganda (p = 0.05), to have higher household incomes (p = 0.003), to have left their home region at younger ages (p < 0.001), to own goats or pigs (p = 0.02) and to rarely or never use shoes (p < 0.001). Similar results were obtained when analyses were restricted to cases and controls with anti-KSHV antibodies. The seroprevalence of KSHV was 79% (63/80) in those with Kaposi's sarcoma as compared to 50% (302/607) in those without (chi(2) heterogeneity (1 df) = 21.0; p < 0.001) and the risk of the tumour increased with increasing anti-KSHV antibody titres (chi(2) trend (1 df) = 29.7; p < 0.001). The risk of Kaposi's sarcoma is clearly linked to antibody status for KSHV, but it would seem that in Uganda other factors are also important in the development of the tumour.

Absence of Kaposi sarcoma among Ethiopian immigrants to Israel despite high seroprevalence of human herpesvirus 8

OBJECTIVE

To determine the prevalence of Kaposi sarcoma (KS) and human herpesvirus 8 (HHV-8) seropositivity in Ethiopian Jewish immigrants to Israel.

METHODS

A Western blot assay was used to determine the seroprevalence of HHV-8 in serum samples from 202 randomly selected human immunodeficiency virus (HIV)-negative and 47 HIV-positive Ethiopian immigrants; samples were obtained on arrival of the immigrants in Israel. The Israel Cancer Registry provided comprehensive data on the occurrence of KS among Ethiopian immigrants and in the non-Ethiopian population of Israel.

RESULTS

A total of 39.1% and 57% of the HIV-negative and HIV-positive Ethiopians, respectively, were infected with HHV-8 (P<.03). However, none of the Ethiopians examined and none of the other HIV-negative Ethiopians among about 45,000 immigrants had KS. Moreover, only 1 (0.85%) of 118 Ethiopian patients with acquired immunodeficiency syndrome (AIDS) developed KS compared with 49 (12.5%) of 391 non-Ethiopian AIDS patients (P<.001).

CONCLUSION

Although HHV-8 infection is common in Ethiopian Jewish immigrants to Israel, these patients almost never develop KS, in marked contrast to the strong association usually observed. The mechanism behind this population's unique protection requires further study.

The epidemiology of conjunctival squamous cell carcinoma in Uganda

As part of a larger investigation of cancer in Uganda, we conducted a case-control study of conjunctival squamous cell carcinoma in adults presenting at hospitals in Kampala. Participants were interviewed about social and lifestyle factors and had blood tested for antibodies to HIV, KSHV and HPV-16, -18 and -45. The odds of each factor among 60 people with conjunctival cancer was compared to that among 1214 controls with other cancer sites or types, using odds ratios, estimated with unconditional logistic regression. Conjunctival cancer was associated with HIV infection (OR 10.1, 95% confidence intervals [CI] 5.2-19.4; P<0.001), and was less common in those with a higher personal income (OR=0.4, 95% CI 0.3-0.7; P<0.001)[corrected]. The risk of conjunctival cancer increased with increasing time spent in cultivation and therefore in direct sunlight (chi2 trend=3.9, P=0.05), but decreased with decreasing age at leaving home (chi2 trend=3.9, P=0.05), perhaps reflecting less exposure to sunlight consequent to working in towns, although both results were of borderline statistical significance. To reduce confounding, sexual and reproductive variables were examined among HIV seropositive individuals only. Cases were more likely than controls to report that they had given or received gifts for sex (OR 3.5, 95% CI 1.2-10.4; P=0.03), but this may have been a chance finding as no other sexual or reproductive variable was associated with conjunctival cancer, including the number of self-reported lifetime sexual partners (P=0.4). The seroprevalence of antibodies against HPV-18 and -45 was too low to make reliable conclusions. The presence of anti-HPV-16 antibodies was not significantly associated with squamous cell carcinoma of the conjunctiva (OR 1.5, 95% CI 0.5-4.3; P=0.5) and nor were anti-KSHV antibodies (OR 0.9, 95% CI 0.4-2.1; P=0.8). The 10-fold increased risk of conjunctival cancer in HIV infected individuals is similar to results from other studies. The role of other oncogenic viral infections is unclear.

AIDS-related malignancies

Cancer remains a significant burden for human immunodeficiency virus (HIV)-infected individuals. Most cancers that are associated with HIV infection are driven by oncogenic viruses, such as Epstein-Barr virus, Kaposi's sarcoma-associated herpesvirus and human papillomavirus. Gaining insight into the epidemiology and mechanisms that underlie AIDS-related cancers has provided us with a better understanding of cancer immunity and viral oncogenesis.

Anti-HIV agent MAP30 modulates the expression profile of viral and cellular genes for proliferation and apoptosis in AIDS-related lymphoma cells infected with Kaposi's sarcoma-associated virus

The anti-HIV agent MAP30 (Momordica anti-HIV protein, 30 kDa) inhibits the proliferation of BC-2, an AIDS-related primary effusion lymphoma (PEL) cell line derived from an AIDS patient. BC-2 cells are latently infected with Kaposi's sarcoma-associated herpes virus (KSHV), also known as human herpes virus 8 (HHV8). We examined the effect of MAP30 on the expression of viral and cellular genes in BC-2 during latent and lytic states of the viral life cycle. By Northern analysis and RT-PCR, we found that MAP30 downregulates the expression of viral cyclin D (vCD), viral interleukin-6 (vIL-6), and viral FLIP (vFLIP), genes involved in cell cycle regulation, viral pathogenesis, and apoptosis. By pathway-specific cDNA microarray analysis, we found that BC-2 cells express high levels of egr-1, ATF-2, hsp27, hsp90, IkappaB, mdm2, skp1, and IL-2, cellular genes involved in mitogenesis, tumorigenesis, and inhibition of apoptosis in NFkappaB and p53 signaling pathways. These results define for the first time the specific cellular pathways involved in AIDS-related tumorigenesis and suggest specific novel targets for the treatment. Furthermore, we found that MAP30 downregulates the expression of egr-1, ATF-2, hsp27, hsp90, IkappaB, mdm2, and Skp1, while it upregulates the pro-apoptotic-related genes Bax, CRADD, and caspase-3. Thus, MAP30 modulates the expression of both viral and cellular genes involved in KS pathogenesis. These results provide valuable insight into the molecular mechanisms of MAP30 anti-KS action and suggest its utility as a therapeutic agent against AIDS-related tumors.

A case-control study of human immunodeficiency virus infection and cancer in adults and children residing in Kampala, Uganda

Uganda offers a unique setting in which to study the effect of human immunodeficiency virus-1 (HIV-1) on cancer. HIV-1 is prevalent there, and cancers which are known to be HIV-associated, such as Kaposi's sarcoma and Burkitt's lymphoma, are endemic. Adults residing in Kampala, Uganda, presenting with cancer in city hospitals were interviewed and had an HIV test. Of the 302 adults recruited, 190 had cancers with a potentially infectious aetiology (cases). The remaining 112 adults with tumours not known to have an infectious aetiology formed the control group. In addition, 318 children who were also Kampala residents were recruited and tested for HIV: 128 with cancer (cases) and 190 with non-malignant conditions (controls). HIV seroprevalence was 24% in adult controls and 6% in childhood controls. The odds of HIV seropositivity among cases with specific cancers (other than Kaposi's sarcoma in adults) were compared with that among controls, using odds ratios (ORs), estimated with unconditional logistic regression. All ORs were adjusted for age (<5, 5-14, 15-19, 30-44, 45+) and sex and, in adults, also for the number of lifetime sexual partners (1 or 2, 3-9, 10+). In adults, HIV infection was associated with a significantly (p < 0.05) increased risk of non-Hodgkin's lymphoma [OR = 6.2, 95% confidence interval (CI) 1.9-19.9, based on 21 cases] and conjunctival squamous-cell carcinoma (OR = 10.9, 95% CI 3.1-37.7, based on 22 cases) but not with cancer at other common sites, including liver and uterine cervix. In children, HIV infection was associated with a significantly increased risk of Kaposi's sarcoma (OR = 94.9, 95% CI 28.5-315.3, based on 36 cases) and Burkitt's lymphoma (OR = 7.5, 95% CI 2.8-20.1, based on 33 cases) but not with other cancers. The pattern of HIV-associated cancers in Uganda is broadly similar to that described elsewhere, but the relative frequency of specific cancers, such as conjunctival carcinoma, in HIV-infected people differs.

Kaposi's sarcoma before and during a human immunodeficiency virus epidemic in Tanzanian children

BACKGROUND

With the onset of AIDS increased frequency of Kaposi's sarcoma (KS) has been reported. However, there is no case-based comparison of childhood (<14 years) KS before and during the HIV pandemic in sub-Saharan Africa. Here we report on the Tanzanian cancer registry data of pediatric KS in Tanzania and implications with regard to pathogenic factors.

METHODS

One hundred fifty histologically confirmed pediatric KS (PKS) cases registered during 1968 through 1995 (28 years) were analyzed with regard to demographic and clinical characteristics before and during the AIDS epidemic. Statistical analysis was done with the Epi-Info program and chi square test.

RESULTS

Of children with PKS 126 (84%) were male and 24 (16%) were female. The gender ratio was 5.1:1 and 5.4:1 during the endemic and epidemic periods, respectively. The highest occurrence of PKS was observed in the 0- to 5-years age group. Overall 73 (4.9/year) of these cases were registered during the pre and 77 (5.9/year) during the AIDS period. Over time a significant increase in anatomically disseminated KS cases was evident during the AIDS epidemic (P = 0.003).

CONCLUSIONS

These observations indicate that children younger than 5 years are at high risk for developing KS, possibly reflecting low resistance to human herpesvirus (HHV) 8 infection. It is also likely that an increased susceptibility to HHV8 infection and morbidity is related to progressive immunodeficiency. The increase in AIDS PKS incidence appears to reflect a direct or indirect promoting effect of HIV on the development of KS lesions. Recognition of the high KS risk in small children warrants considerations of possible prevention measures including HIV/HHV8 vaccination and therapeutic options.