The role of p53 and HPV in cervical cancer

The role of human papillomavirus in squamous carcinoma of the head and neck

Human papillomavirus type-16 infection is associated with a significant portion of squamous carcinoma of the head and neck, particularly for the oropharynx and for those lacking the other risk factors of tobacco and alcohol. The link between human papillomavirus type-16 and carcinoma of the oropharynx is based on the identification of human papillomavirus type-16 in oropharyngeal tumors and the association of human papillomavirus type-16 with the risk of oropharyngeal cancer estimated in case-control epidemiologic studies. This review highlights the molecular mechanism of human papillomavirus carcinogenesis and the association of human papillomavirus type-16 as a risk factor for squamous cell carcinoma of the oropharynx as well as recent research efforts utilizing human papillomavirus as a biomarker of clinical outcomes.

TP73 alterations in cervical carcinoma

Infection with human papillomaviruses (HPV) is essential in the carcinogenesis of the uterine cervix. However, a complex interrelation between viral and cellular genes is necessary for cell-cycle control deregulation and development and progression of cervical cancer induction. The TP73 gene is localized in 1p36.3 band, which is often deleted by loss of heterozygosity (LOH) in human cancers. We analyzed the p73 cytosine thymine polymorphism and LOH in this locus by polymerase chain reaction restriction fragment length polymorphism in 134 DNA samples from biopsies of 67 primary untreated invasive cervix tumors and the corresponding peripheral blood. Genotype frequencies of 56.7% for homozygous genotype GC/GC and 43.3% for heterozygous genotype GC/AT were found. The presence of the GC/AT genotype in tumors was associated with lower age at menarche (P=0.039) and high parity (P=0.015). In 20.0% of DNA tumor samples, the AT allele was lost compared with their DNA normal blood pairs. The AT allele was conserved in women with high parity. This was not the case in the group with low parity, with 33.3% of patients showing loss of the AT allele in tumor DNA (P=0.041). These results suggest that TP73 genetic alterations may contribute to the genesis and/or progression of cervical carcinoma in an HPV-infected transformation zone under prolonged exposure to events related to pregnancy.

The impact of tumour angiogenesis, p53 overexpression and proliferative activity (MIB-1) on survival in squamous cervical carcinoma

Tumour angiogenesis (antifactor VIII-related antigen antibody), p53 overexpression (DO-1) and proliferative activity (MIB-1) were immunohistochemically analysed for the prediction of long-term survival in 113 patients with squamous cervical carcinoma. The median follow-up time was 82 months (range 72-99). In early stages (IB-IIA), neovascularisation was significantly related to tumour size. Significantly more patients in stage IIA had high tumour vascularity compared to stage IB (P < 0.01) but no significant difference was found between early and advanced stages (IIB-IVB) of cervical carcinoma. p53 overexpression was correlated to the stage of disease (P < 0.01). No relationship was found between tumour angiogenesis, p53 overexpression or MIB-1 and pelvic lymph node metastases, histological subtype or differentiation. Tumours with more than 50% p53 overexpression was significantly correlated with survival in the univariate analysis, but no independent predictive value was found. It is concluded that immunohistochemically detectable p53 overexpression as measured by DO-1 and proliferative activity as measured by MIB-1 seems of no clinical value for the prediction of long-term survival in squamous cervical carcinoma. The predictive value of tumour angiogenesis for survival outcome has still to be determined in squamous cervical carcinoma.

Neoplastic transformation of the endocervix associated with downregulation of lactoferrin expression

The incidence of cervical adenocarcinomas in young women over the last two decades has increased. Even with increasing knowledge of the role of human papillomavirus in the etiology of adenocarcinoma of the cervix, there is a paucity of data concerning the genetic and epigenetic factors that contribute to the histologic features and biologic behaviors of these tumors. Lactoferrin is a basic glycoprotein found in human milk, secondary granules of neutrophils, and many body secretions, and it has been associated with carcinogenesis of the endometrium, breast, and lymphoid systems. In this study, we examined the expression of lactoferrin in normal human endocervical epithelium and in cervical adenocarcinomas in relation to proliferative index, steroid receptor status, p53 protein expression, and apoptosis. Immunohistochemical and in situ studies demonstrated that lactoferrin protein and mRNA were strikingly downregulated upon neoplastic transformation of the endocervix as early as in adenocarcinoma in situ when compared with the prominent expression exhibited by the normal cervical epithelium. Furthermore, neoplastic transformation of endocervical epithelial cells was accompanied by a pronounced stimulation of proliferation and a substantial reduction in the expression of the estrogen and progesterone receptors and p53 but little or no change in the number of apoptotic cells. In conclusion, we identified lactoferrin as a novel cancer-specific marker of endocervical adenocarcinomas that may be useful in the early detection of the disease, prediction of prognosis, and the development of new therapeutic modalities.