Cervical cancer ranks as the first most frequent cancer among women in Benin. The major cause of cervical cancer now recognized is persistent infection of Human Papillomavirus (HPV). In Benin there is a lack of screening programs for prevention of cervical cancer and little information exists regarding HPV genotype distribution.

The cancer stem cell hypothesis suggests that mutated melanocyte stem cells are present in skin as precursors of melanoma cells. Nestin and CD133 have been described as markers of melanocytic stem cells. The aim of this study was to establish if melanocytic stem cells could have a prognostic significance in melanoma progression. An immunohistochemical study for nestin and CD133 was performed in 130 primary tumors and 32 nodal metastasis biopsy specimens to evaluate possible differences, and to compare the results with survival data and clinicopathological variables. Nestin was expressed in cytoplasm of non-pigmented tumor cells and in endothelial cells, especially at the invading tumor front. Nestin staining in stage I and II (according to the American Joint Committee on Cancer Staging system) melanoma patients significantly predicted poor survival (log-rank test, P=0.037), with lower survival rates in cases with nestin positivity in both tumoral and endothelial cells. CD133 staining was not associated with survival. There were no significant differences in nestin or CD133 expression between primary tumors and metastases. These results suggest that nestin expression in both tumoral and endothelial cells may be considered an important early prognostic marker in melanoma.

8-hydroxy-2'-deoxyguanosine (8-OHdG) is one of the main mutagenic modifications induced in DNA by oxidative stress. Elevated levels of 8-OHdG have been regarded as an independent prognostic factor in different types of cancer. Various enzymes, such as human 8-oxoguanine DNA-glycosylase 1 (hOGG1) and glucose-6-phosphate dehydrogenase (G6PD), act as protection against oxidative stress. The low activity of such enzymes has been consistently associated with increased risk of progression in several tumor types. The aim of this study was to investigate whether 8-OHdG, hOGG1 and G6PD expression in tumor tissues might be a predictor of survival in melanoma patients. The expression of 8-OHdG, hOGG1 and G6PD was immunohistochemically investigated in primary cutaneous melanoma and the effect on survival was analyzed. Furthermore, the immunostaining for p53 and survivin was evaluated and the relationship among 8-OHdG, hOGG1, G6PD, p53 and survivin expression was analyzed. Kaplan-Meier analysis demonstrated that patients with low expression of nuclear 8-OHdG had significantly longer survival time compared with those with a high expression (P=0.032), whereas cancer-specific survival of patients was not associated with hOGG1 or G6PD expression. These results suggest an involvement of oxidative DNA damage in the process of melanoma pathogenesis and demonstrate that 8-OHdG expression in nuclei of tumor cells could be useful as an early independent prognostic marker in patients with primary cutaneous melanoma.

Pterygium, an ultraviolet radiation (UV)-related disease, is a relatively benign process, but since it displays tumor-like features, it has been proposed to be a neoplastic- like growth disorder. Vitamin D performs a number of functions in addition to calcium homeostasis, as inhibition of cell proliferation, activation of apoptotic pathways, and inhibition of angiogenesis. Since the antitumor actions of vitamin D are mediated primarily through the nuclear vitamin D receptor (VDR), the aim of the present study was to investigate vitamin D status in patients with pterygium and in control subjects, and VDR immunohistochemical expression in samples of pterygium and normal conjunctiva in order to evaluate a possible role of vitamin D pathway in the pathogenesis of the disease. Serum vitamin D concentration was measured among 41 patients with pterygium and 47 volunteers by an automated chemiluminescence immunoassay. Moreover, 23 formalin- fixed and paraffin-embedded pterygium biopsy samples and 24 conjunctiva specimens were treated for the immunohistochemical demonstration of VDR using the streptavidin-biotin alkaline phosphatase method. No differences were observed about vitamin D level between patient with pterygium and control group, but significant differences between VDR immunolocalization in pterygium and normal conjunctiva were observed (P=0.00001). In conjunctiva, the immunoreactivity, localized mainly in cytoplasm of epithelial cells, may probably demonstrate VDR regulation of cell growth, differentiation, and apoptosis, while in pterygium VDR co-localization in the nucleus and cytoplasm of epithelial cells may indicate alternative nuclear pathways by which vitamin D might exert its antiinflammatory and anti-proliferative effects by the regulation of gene expression.

Pterygium is a multifactorial disease in which UV-B is speculated to play a key role by inducing oxidative stress and phototoxic DNA damage. In search for candidate molecules that are useful for justifying the intense epithelial proliferation observed in pterygium, our attention has been focused on Insulin-like Growth Factor 2 (IGF-2), mainly detected in embryonic and fetal somatic tissues, which regulate metabolic and mitogenic functions. The binding between IGF-2 and its receptor Insulin-like Growth Factor 1 Receptor (IGF-1R) activates the PI3K-AKT pathway, which leads to the regulation of cell growth, differentiation, and the expression of specific genes. Since IGF2 is regulated by parental imprinting, in different human tumors, the IGF2 Loss of Imprinting (LOI) results in IGF-2- and IGF2-derived intronic miR-483 overexpression. Based on these activities, the purpose of this study was to investigate the overexpression of IGF-2, IGF-1R, and miR-483. Using an immunohistochemical approach, we demonstrated an intense colocalized epithelial overexpression of IGF-2 and IGF-1R in most pterygium samples (Fisher’s exact test, p = 0.021). RT-qPCR gene expression analysis confirmed IGF2 upregulation and demonstrated miR-483 expression in pterygium compared to normal conjunctiva (253.2-fold and 12.47-fold, respectively). Therefore, IGF-2/IGF-1R co-expression could suggest their interplay through the two different paracrine/autocrine IGF-2 routes for signaling transfer, which would activate the PI3K/AKT signaling pathway. In this scenario, miR-483 gene family transcription might synergically reinforce IGF-2 oncogenic function through its boosting pro-proliferative and antiapoptotic activity.