Browsing by Author "Govan, Vandana"

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    The allelic distribution of -308 Tumor Necrosis Factor-alpha gene polymorphism in South African women with cervical cancer and control women
    (BioMed Central Ltd, 2006) Govan, Vandana; Constant, Debbie; Hoffman, Margaret; Williamson, Anna-Lise
    BACKGROUND:Cervical cancer is due to infection with specific high-risk types of human papillomavirus (HPV). Although the incidence of genital HPV infection in various population groups is high, most of these regress without intervention. Investigating genetic host factors and cellular immune responses, particularly cytokines, could help to understand the association between genital HPV infection and carcinogenesis. The tumor necrosis factor alpha (TNF-alpha) cytokine plays an important role in all stages of cervical cancer and has the ability to induce the regression of human tumors. Therefore the aim of the study was to investigate the allelic distribution of -308 TNF-alpha gene polymorphism in South African women with cervical cancer compared to control women. METHODS: Included in our study were women with histologically proven cancer of the cervix (n = 244) and hospital-based controls (n = 228). All patients and controls were from mixed race and black population groups in South Africa. The detection of a bi-allelic -308 (A/G) polymorphism in the promoter region of TNF-alpha was investigated using the amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) technique. The distributions of the allelic frequencies were stratified in both patients and controls into two South African ethnic population groups. RESULTS: In this study we observed no association between the distribution of -308 TNF-alpha polymorphism and the risk of developing cervical cancer even after combining the data from the two ethnic populations (X2 = 2.26). In addition, using the chi-squared test we found no significant association between the known risk factors for cervical cancer and the allele distribution of -308 TNF-alpha. However, the frequency of the rare high-producing allele -308A of TNF-alpha was significantly lower in the South African population when compared to Caucasians and Chinese population groups. CONCLUSION: We demonstrated no association between -308 TNF-alpha polymorphism and the risk of cervical cancer among two South African ethnic population groups. However, as the distribution of the -308A TNF-alpha was notably different between the control groups of South Africa and other population groups this result suggests that ethnic disparity may influence the levels of TNF-alpha produced.
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    Therapeutic immunisation of rabbits with cottontail rabbit papillomavirus (CRPV) virus-like particles (VLP) induces regression of established papillomas
    (BioMed Central Ltd, 2008) Govan, Vandana; Rybicki, Edward; Williamson, Anna-Lise
    There is overwhelming evidence that persistent infection with high-risk human papillomaviruses (HR-HPV) is the main risk factor for invasive cancer of the cervix. Due to this global public health burden, two prophylactic HPV L1 virus-like particles (VLP) vaccines have been developed. While these vaccines have demonstrated excellent type-specific prevention of infection by the homologous vaccine types (high and low risk HPV types), no data have been reported on the therapeutic effects in people already infected with the low-risk HPV type. In this study we explored whether regression of CRPV-induced papillomas could be achieved following immunisation of out-bred New Zealand White rabbits with CRPV VLPs. Rabbits immunised with CRPV VLPs had papillomas that were significantly smaller compared to the negative control rabbit group (P [less than or equal to] 0.05). This data demonstrates the therapeutic potential of PV VLPs in a well-understood animal model with potential important implications for human therapeutic vaccination for low-risk HPVs.