High frequency of human papillomavirus 6/11, 16, and 18 infections in precancerous lesions and squamous cell carcinoma of the conjunctiva in subtropical Tanzania

Dysplastic lesions and epithelial neoplasms of the conjunctiva account for approximately 2% of all malignant tumors in subtropical Tanzania. We examined the pathophysiologic role of human papillomavirus (HPV) in the development of conjunctival carcinoma in subtropical Tanzania, which has a high HPV prevalence. Tissue samples from 14 patients were obtained from the cancer registry archives at the medical center of the university in Dar es Salaam, Tanzania. A highly sensitive nonradioactive in situ hybridization technique (ImmunoMax) was applied to paraffin-embedded tissue samples to identify HPV DNA in conjunctival epithelial dysplasia and epithelial neoplasms. In each case, conventional morphologic evaluation revealed a transitional lesion extending from koilocytic dysplasia to severe dysplasia or invasive squamous cell carcinoma. Highly specific, morphologically easily distinguishable labeling of HPV-6/11, HPV-16, and HPV-18 was found in most cases. Coinfections were observed frequently. The signals showed varying intensities and different patterns of distribution. In general, higher signal intensity was found in dysplasia grades 1 and 2 and in well-differentiated areas of the invasive component of conjunctival carcinoma compared with less differentiated areas. This observation underlines the central role of HPV-16 and HPV-18 in the oncogenesis of conjunctival cancers in subtropical Tanzania.

Risk factors for cervical squamous intraepithelial lesions among HIV-1 seropositive women in Dar es Salaam, Tanzania

OBJECTIVES

To determine the prevalence and risk factors for cervical squamous intraepithelial lesions (SIL) among HIV-infected women in Dar es Salaam, Tanzania.

METHODS

Between July 1996 and December 1997 we interviewed 691 HIV-infected women to obtain information about risk factors for SIL. Cervical smears and samples for lymphocyte subsets and sexually transmitted diseases (STD) diagnosis were collected.

RESULTS

The prevalence of SIL was 2.9% (20/686) (95% CI = 1.7-4.2%). Eleven women had low-grade SIL while nine women had high-grade SIL. The number of lifetime sexual partners and live births was associated with a marginally non-significant increased risk of SIL. The risk of SIL was significantly increased among women with CD4+ cell count < 200/mm3 (multivariate odds ratio (OR) = 6.15, 95% CI = 1.19-41.37) and decreased by 68% for each 5-cm increase in mid-upper arm circumference (multivariate OR = 0.32, 95% CI = 0.10-0.93).

CONCLUSIONS

HIV-related immunosuppression and wasting and long-term sexual behavior were the major determinants of SIL in this population. Federation of Gynecology and Obstetrics.

Carcinoma of the uterine cervix associated with schistosomiasis and induced by human papillomaviruses

OBJECTIVES

To determine the presence of human papillomaviruses (HPVs) in cervical cancer among patients in Tanzania and to ascertain their prevalence in cases associated with schistosomiasis.

METHODS

In situ hybridization was applied to 31 carcinomas of the uterine cervix including 10 in which schistosomiasis co-occurred. Twenty-six cases in this series also exhibited koilocytic dysplasia.

RESULTS

Twenty-six out of 31 cases revealed a specific hybridization for HPVs with varying density and distribution. A slightly higher labeling of HPV-16 than -18 was demonstrated. All schistosomiasis-associated cancers encoded the papillomaviruses. The 31 patients were predominantly young adults, a fact that reflects sexual activity at a very young age in the ethnic communities of Africa.

CONCLUSION

These findings shed new light on the presumed etiologic implication of schistosomiasis in the genesis of cervical cancer. In the absence of HPV, schistosomiasis is not the oncogenic causative agent for carcinoma of the uterine cervix.

Carcinoma of the uterine cervix and schistosomiasis

OBJECTIVES

To determine the incidence of carcinoma of the uterine cervix and its relationship to schistosomiasis infection.

METHODS

A retrospective analysis of a 10-year period (1980-1990) at the department of histopathology (cancer registry) of the University of Dar es Salaam using statistical evaluation of the proportional rate of histomorphological diagnosis, clinical symptoms and epidemiological aspects.

RESULTS

There were 4520 cases classified as cervical carcinoma. Unexpectedly, only 76 of these (1.7%) revealed an association with schistosomiasis. Precancerous lesions of the squamous epithelium of the uterine cervix were a relatively common feature in carcinoma of both groups. Furthermore, epidemiological analysis indicates that the occurrence of cancer and schistosomiasis infection of the cervix is not strictly confined to the population of rural regions, known as endemic areas, with low hygienic and socioeconomic standards. This fact is most probably due to the rural people moving into urban areas, hoping to improve their quality of life.

CONCLUSIONS

Our data do not support the assumption of an etiologic role of schistosomiasis in the oncogenesis of cervical carcinoma.