Greta Dreyer

Bio: Greta Dreyer is an academic researcher from University of Pretoria. The author has contributed to research in topics: Cervical cancer & Population. The author has an hindex of 14, co-authored 59 publications receiving 691 citations.

Human papillomavirus prevalence and type distribution in invasive cervical cancer in sub-Saharan Africa.

Abstract: In sub-Saharan Africa, invasive cervical cancer (ICC) incidence and mortality are among the highest in the world This cross-sectional epidemiological study assessed human papillomavirus (HPV) prevalence and type distribution in women with ICC in Ghana, Nigeria, and South Africa Cervical biopsy specimens were obtained from women aged ≥ 21 years with lesions clinically suggestive of ICC Histopathological diagnosis of ICC was determined by light microscopy examination of hematoxylin and eosin stained sections of paraffin-embedded cervical specimens; samples with a confirmed histopathological diagnosis underwent HPV DNA testing by polymerase chain reaction HPV-positive specimens were typed by reverse hybridization line probe assay Between October 2007 and March 2010, cervical specimens from 659 women were collected (167 in Ghana, 192 in Nigeria and 300 in South Africa); 570 cases were histologically confirmed as ICC The tumor type was identified in 551/570 women with ICC; squamous cell carcinoma was observed in 476/570 (835%) cases The HPV-positivity rate in ICC cases was 904% (515/570) In ICC cases with single HPV infection (447/515 [868%]), the most commonly detected HPV types were HPV16 (512%), HPV18 (172%), HPV35 (87%), HPV45 (74%), HPV33 (40%) and HPV52 (22%) The prevalence of single and multiple HPV infections seemed higher among HIV-positive women and HPV type distribution appeared to differ according to tumor type and HIV status In conclusion, HPV16, 18, 45 and 35 were the most common HPV types in sub-Saharan African women with ICC and HPV infections were more common in HIV-positive women

BRCA1 mutations in South African breast and/or ovarian cancer families: Evidence of a novel founder mutation in Afrikaner families

Abstract: Germ-line mutations within BRCA1 are responsible for different proportions of inherited susceptibility to breast/ovarian cancer, and the spectrum of mutations within this gene is often unique to certain populations. At this time, there have been no reports regarding the role of BRCA1 in South African breast and/or ovarian cancer families. We therefore screened 90 South African breast/ovarian cancer families for BRCA1 mutations by means of PCR-based mutation detection assays. Eighteen families (20%) were identified with BRCA1 disease-causing mutations. Four Ashkenazi Jewish families were identified with the 185delAG mutation, whereas 2 Afrikaner and 1 Ashkenazi Jewish family were found to harbor the 5382insC mutation. Five of the families (5.56%), all of whom are Afrikaners, were found to carry the novel E881X mutation. Genotype analyses show that these patients share a common ancestor. Genealogic studies have identified 3 possible founding couples for this mutation, all of whom arrived in the Cape from France in the late 1600s. Of the remaining mutations detected, 3 have not been reported previously and include the S451X, 1493delC (detected twice) and 4957insC mutations. © 2004 Wiley-Liss, Inc.

Age-specific prevalence of cervical human papillomavirus infection and cytological abnormalities in women in Gauteng Province, South Africa

Abstract: Background. Women accessing the public health system in Gauteng province, South Africa are largely unscreened for cervical cancer andhave a high background prevalence of human immunodeficiency virus (HIV) infection.Objectives. This cross-sectional study describes the age-specific prevalence of human papillomavirus (HPV) infection and cytologicalabnormalities among this urban and peri-urban population.Method. Over the period March 2009 - September 2011, 1 524 women attending public sector primary healthcare clinics were invited toparticipate in a cervical cancer screening study. All participants were screened with conventional cytology and HPV testing undertaken using the HPV linear array genotyping kit (Roche Molecular Systems).Results. Of 1 472 women with valid cytology results, abnormalities were detected in 17.3% (n=255), of which 9.1% (n=134) were high-gradesquamous intraepithelial lesions, and 0.5% (n=8) suggestive of squamous carcinoma. Of the 1 445 women with complete data, the overall and high-risk HPV DNA prevalences were 74.6% (n=1 078) and 54.3% (n=784), respectively. HPV type 16 and/or 18 were detected in 19.5% (n=282) of women. Age-specific prevalence of HPV showed a plateau-shaped curve.Conclusions. The prevalences of HPV infection and abnormal cytology were much higher than previously reported in general populations in South Africa and elsewhere. Higher age-specific prevalence and similar plateau-like age-specific epidemiological curves have previouslyonly been described in studies among HIV-positive women. These findings have implications for planning and development of cervical screening programmes in developing countries with largely unscreened populations with a high background prevalence of HIV.

Universal Declaration of Human Rights

Abstract: It made it possible to improve people's lives. Now it prevents all forms of discrimination in the world. It helps to improve our world.

Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis

Abstract: BACKGROUND Human papillomavirus (HPV) vaccination programmes were first implemented in several countries worldwide in 2007. We did a systematic review and meta-analysis to assess the population-level consequences and herd effects after female HPV vaccination programmes, to verify whether or not the high efficacy reported in randomised controlled clinical trials are materialising in real-world situations. METHODS We searched the Medline and Embase databases (between Jan 1, 2007 and Feb 28, 2014) and conference abstracts for time-trend studies that analysed changes, between the pre-vaccination and post-vaccination periods, in the incidence or prevalence of at least one HPV-related endpoint: HPV infection, anogenital warts, and high-grade cervical lesions. We used random-effects models to derive pooled relative risk (RR) estimates. We stratified all analyses by age and sex. We did subgroup analyses by comparing studies according to vaccine type, vaccination coverage, and years since implementation of the vaccination programme. We assessed heterogeneity across studies using I(2) and χ(2) statistics and we did trends analysis to examine the dose-response association between HPV vaccination coverage and each study effect measure. FINDINGS We identified 20 eligible studies, which were all undertaken in nine high-income countries and represent more than 140 million person-years of follow-up. In countries with female vaccination coverage of at least 50%, HPV type 16 and 18 infections decreased significantly between the pre-vaccination and post-vaccination periods by 68% (RR 0·32, 95% CI 0·19-0·52) and anogenital warts decreased significantly by 61% (0·39, 0·22-0·71) in girls 13-19 years of age. Significant reductions were also recorded in HPV types 31, 33, and 45 in this age group of girls (RR 0·72, 95% CI 0·54-0·96), which suggests cross-protection. Additionally, significant reductions in anogenital warts were also reported in boys younger than 20 years of age (0·66 [95% CI 0·47-0·91]) and in women 20-39 years of age (0·68 [95% CI 0·51-0·89]), which suggests herd effects. In countries with female vaccination coverage lower than 50%, significant reductions in HPV types 16 and 18 infection (RR 0·50, 95% CI 0·34-0·74]) and in anogenital warts (0·86 [95% CI 0·79-0·94]) occurred in girls younger than 20 years of age, with no indication of cross-protection or herd effects. INTERPRETATION Our results are promising for the long-term population-level effects of HPV vaccination programmes. However, continued monitoring is essential to identify any signals of potential waning efficacy or type-replacement. FUNDING The Canadian Institutes of Health Research.