Biomedical subjects

Heather Cubie

Publications and source records attributed to Heather Cubie.

3 recordsLinked to original sources

PubMed2005

High prevalence of high-risk oncogenic human papillomaviruses harboring atypical distribution in women of childbearing age living in Libreville, Gabon.

The extent of human papillomavirus (HPV) genital shedding and type-specific diversity were evaluated in 354 consecutive women of childbearing age living in Libreville, Gabon. Detection of HPV DNA was performed by PCR using the MY09/MY11 primer set on DNA extracted from endocervical swabs. All PCR positive specimens were subjected to direct sequencing and HPV genotypes were identified on the basis of >95% sequence homology in the L1 region. Reverse line blot hybridization assay was used when a genotype could not be resolved by sequencing alone. HPV DNA was detected in 163 (46%) women, all clinically asymptomatic for HPV-related lesions. The highest prevalence of genital HPV detection (45%) was in the age group from 22 to 29 years. A total of 90 women (55%) harbored high-risk (HR) genotypes, with the most common being HPV-53 (19; 12%), HPV-58 (17; 11%), and HPV-16 (16; 10%). Low-risk genotypes were found in 36 (22%) women with HPV-54 and HPV-70 being the most frequently detected (17; 11% and 10; 6%, respectively). Finally 37 women (23%) tested positive for genotypes of unknown oncogenic risk, the most common in this category being HPV-83 (20; 12%). Multiple infections were detected in 35 (21%) women. By multivariate analysis, HPV genital shedding was significantly associated with young age (OR: 0.34; P < 0.007). The multivalent vaccine currently available against cervical carcinomas, is only active against HPV-16 and HPV-18, and will thus have a low impact in this setting.

Adolescent↗

PubMed2005

Molecular basis for advances in cervical screening.

Human papillomaviruses (HPVs) cause cervical lesions, which can, in some instances, progress to high-grade neoplasia and cancer. Around half a million cases of cervical cancer occur each year, with most occurring in developing countries where cervical cancer is a major cause of cancer-related death. The reduction in cervical cancer incidence in developed countries is largely attributed to the introduction of cervical screening. Cervical screening currently depends on the identification by cytology of abnormalities in cells taken from the surface of the cervix. The standard Pap test was developed >50 years ago, and despite modifications, still forms the basis of the test currently in use in most routine screening laboratories. Advances in our understanding of the molecular mechanisms that lead to the development of cervical cancer have been slow to impact on screening, despite the relatively high false-negative rates that can be associated with the conventional Pap smear. Improvements in screening strategies fall into a number of categories. Methods that improve cell presentation and attempt to eliminate artefacts/obscuring debris can be combined with image analysis systems in order to enhance diagnostic accuracy. Such approaches still rely on cytological evaluation and do not incorporate advances in our knowledge of how HPV causes cancer. By contrast, markers of virus infection or cell cycle entry, particularly those that offer some degree of prognostic significance, may be able to highlight abnormal cells more reliably than cytology, and could be combined with cytology to improve the detection rate. Our understanding of the molecular biology of HPV infection and the organization of the HPV life-cycle during cancer progression provides a rational basis for marker selection. The general assumption that persistent active infection by high-risk HPV types is the true precursor of cervical cancer provides the rationale for HPV DNA testing in conjunction with enhanced cytology, while the development of RNA-based approaches should allow active infections to be distinguished from those that are latent. The detection in superficial cells of marker combinations at the level of RNA or protein has the potential to predict disease status more precisely than the detection of markers in isolation. There is also a need for better prognostic markers if the predictive value of screening is to be improved. The potential to control infection by vaccination should reduce the incidence of HPV-associated neoplasia in the population, and this may cause a change in the way that screening is carried out. Nevertheless, the lack of a therapeutic vaccine, and the difficulties associated with eliminating infection by multiple high-risk HPV types, means that some form of screening will still be required as a preventive measure for the control of cervical cancer for the foreseeable future.

Alphapapillomavirus↗

PubMed2004

Assessment of human papillomavirus mRNA detection over time in cervical specimens collected in liquid based cytology medium.

Little is known about the stability of human papillomavirus (HPV) RNA within cervical samples collected in liquid based cytology (LBC) preservation media. We addressed this by analysing patient LBC specimens for the presence of HPV RNA over a prospective time course. LBC samples in PreservCyt were obtained from seven women referred to colposcopy due to a cytological diagnosis of moderate or severe dyskaryosis. Aliquots were removed and subject to RNA extraction at, 6h (base-line), 4, 7 and 14 days, post-collection. HPV mRNA was detected using the PreTect HPV Proofer, which detects HPV 16, 18, 31, 33 and 45 E6/E7 transcripts and human small ribonucleoprotein U1A mRNA as a sample control. HPV DNA genotyping was also performed at base-line to assess the range of types in our group. In addition to assessment of viral RNA, overall integrity of the cellular RNA extract was analysed by the RNA 6000 pico assay. Control human RNA was amplified successfully in all seven samples at each time point. Five of the seven women were HPV positive for E6/E7 viral transcripts at base-line and positivity was maintained in all five up to 14 days. Although the pattern of cellular RNA profiles generated from the samples was variable, results indicated that this extract could be amenable to gene expression profiling and that degradation did not increase as a result of storage time. It is concluded that HPV RNA in routinely collected LBC specimens in PreservCyt can be detected for at least 14 days from sample collection.

Cervix Uteri↗