Human papillomavirus profile of women in Belize City, Belize: correlation with cervical cytopathologic findings.

Cervical carcinoma is the most common cancer among Belizean women; however, data regarding the frequency of human papillomavirus (HPV) genotypes and their association with cervical cancer are nonexistent. We therefore included HPV genotyping as part of a week-long cervical cancer screening campaign conducted in Belize City in 2007. Conventional Papanicolaou smears with Hybrid Capture (HC) 2 HPV testing were performed on 463 women. All HC2-positive samples were genotyped using a developmental GP5+/GP6+ polymerase chain reaction-coupled Luminex assay for 2 low-risk and 18 high-risk HPV types. The prevalence of high-risk HPV was 15.6% in the total population, 10.1% in those with normal cytologic findings, and 93.3% in women with a high-grade squamous intraepithelial lesion. Of patients with HPV infections, 35% had multiple types (5.4% of the total group). Of all women and of women with normal cytologic findings, 5.2% and 2.8%, respectively, had HPV16 or 18. For all women, HPV16, 18, 56, and 52 were present in decreasing order of frequency. HPV11 was present in only one patient, and none had HPV6. HPV16 was found in 47% of high-grade squamous epithelial lesions; however, no case of HSIL had HPV18 or 45. HPV35 and HPV58 were the next most common types in high-grade squamous intraepithelial lesion, each occurring in 20% of cases of high-grade squamous intraepithelial lesion, followed by HPV31 in 13.3%. Although women younger than 25 years old were underrepresented, these data suggest that the HPV profile of this cohort of Belizean women differs somewhat from that in the region. In addition, these data are of importance with regard to the development of HPV vaccines that will be used in less developed countries, where care should be taken not to implement vaccination at the cost of basic screening and diagnostic services.

Critical role of oxidative stress in estrogen-induced carcinogenesis.

Mechanisms of estrogen-induced tumorigenesis in the target organ are not well understood. It has been suggested that oxidative stress resulting from metabolic activation of carcinogenic estrogens plays a critical role in estrogen-induced carcinogenesis. We tested this hypothesis by using an estrogen-induced hamster renal tumor model, a well established animal model of hormonal carcinogenesis. Hamsters were implanted with 17beta-estradiol (betaE2), 17alpha-estradiol (alphaE2), 17alpha-ethinylestradiol (alphaEE), menadione, a combination of alphaE2 and alphaEE, or a combination of alphaEE and menadione for 7 months. The group treated with betaE2 developed target organ specific kidney tumors. The kidneys of hamsters treated with alphaE2, alphaEE, or menadione alone did not show any gross evidence of tumor. Kidneys of hamsters treated with a combination of alphaE2 and alphaEE showed early signs of proliferation in the interstitial cells. Kidneys of hamsters treated with a combination of menadione and alphaEE showed foci of tumor with congested tubules and atrophic glomeruli. betaE2-treated tumor-bearing kidneys showed >2-fold increase in 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) levels compared with untreated controls. Kidneys of hamsters treated with a combination of menadione and alphaEE showed increased 8-iso-PGF(2alpha) levels compared with untreated controls, whereas no increase in 8-iso-PGF(2alpha) was detected in kidneys of alphaEE-treated group. A chemical known to produce oxidative stress or a potent estrogen with poor ability to produce oxidative stress, were nontumorigenic in hamsters, when given as single agents, but induced renal tumors, when given together. Thus, these data provide evidence that oxidant stress plays a crucial role in estrogen-induced carcinogenesis.

Skin tumors in aging Long Evans rats.

We report 25 cases of skin neoplasm observed among 30 Long Evans rats serving as controls in a psychosocial behavioral study conducted in the Vivarium at Charles R. Drew University, Los Angeles, CA. The animals were 10 weeks old at the beginning of the study. All the skin tumors developed at 18 to 26 months of age and slowly enlarged over a period of 9 months. Multiple nodules occurred in 8 males and 6 females. None of the tumors regressed. The tumors were located around the hind leg and dorso-medial area and measured 1 to 2 cm. Physical examination revealed firm well demarcated dermal masses. Most of the tumor nodules were intradermal, and some had a central ulcerated or keratin-filled core. Microscopic examination performed on some of the tumors showed findings of classic Keratoacanthoma, whereas others showed histologic features suggestive of squamous cell carcinoma. These findings indicate a high rate (83%) of spontaneous skin neoplasms among aging Long Evans rats. To our knowledge, such a high rate of skin neoplasms in aged rodents has not been described in the literature. Furthermore, further studies should be undertaken to confirm these findings and to assess whether these rodents might serve as a model for studying the alterations in the immune system with aging.