This review examines the association between the apolipoprotein (apo) var epsilon gene polymorphism (or its protein product (apo E)), metabolic regulation of cholesterol, and cardiovascular disease. The apo var epsilon gene is located at chromosome 19q13.2. Among the variants of this gene, alleles (*) epsilon2, (*) epsilon3, and (*) epsilon4 constitute the common polymorphism found in most populations. Of these variants, apo (*) epsilon3 is the most frequent (>60%) in all populations studied. The polymorphism has functional effects on lipoprotein metabolism mediated through the hepatic binding, uptake, and catabolism of chylomicrons, chylomicron remnants, very low density lipoprotein (VLDL), and high density lipoprotein subspecies. Apo E is the primary ligand for two receptors, the low density lipoprotein (LDL) receptor (also known as the B/E receptor) found on the liver and other tissues and an apo E-specific receptor found on the liver. The coordinate interaction of these lipoprotein complexes with their receptors forms the basis for the metabolic regulation of cholesterol. Allelic variation in apo var epsilon is consistently associated with plasma concentrations of total cholesterol, LDL cholesterol, and apo B (the major protein of LDL, VLDL, and chylomicrons). Apo var epsilon has been studied in disorders associated with elevated cholesterol levels or lipid derangements (i.e., hyperlipoproteinemia type III, coronary heart disease, strokes, peripheral artery disease, and diabetes mellitus). The apo var epsilon genotype yields poor predictive values when screening for clinically defined atherosclerosis despite positive, but modest associations with plaque and coronary heart disease outcomes. In addition to genotype-phenotype associations with vascular disease, the alleles and isoforms of apo var epsilon have been related to dementias, most commonly Alzheimer's disease.
Purpose Cytology-based screening has limited sensitivity to detect prevalent cervical precancers. HPV DNA testing is highly sensitive and provides a high, long-term reassurance of low risk of cervical cancer. However, the specificity of HPV DNA testing is limited, requiring additional, more disease-specific markers for efficient screening approaches. Experimental Design Liquid based cytology samples were collected from 625 women referred to colposcopy. A slide was stained using the CINtec plus cytology assay. Pap cytology and HPV genotyping were performed from the same vial. Clinical performance characteristics were calculated for all women, stratified by age, and for women referred with an LSIL Pap. Results p16/Ki-67-positivity increased with histological severity, from 26.8% in normal histology, 46.5% in CIN1, 82.8% in CIN2, to 92.8% in CIN3. Among women with CIN3, p16/Ki-67-positivity increased from 77.8% for women <30 years without HPV16 to 100% for women 30 years and older with HPV16. The sensitivity and specificity to detect CIN3+ were 93.2% and 46.1%, respectively, and increased to 97.2% and 60.0% among women 30 years and older. In women with HR-HPV-positive ASC-US and LSIL, sensitivity and specificity for detection of CIN3 were 90.6% and 48.6%, respectively. Conclusions p16/Ki-67 testing could reduce referral to colposcopy by almost half while detecting the most severe cases of CIN3. The high sensitivity of p16/Ki-67 with significantly improved specificity compared to HPV testing makes p16/Ki-67 a viable option for LSIL triage. Further studies are required to evaluate p16/Ki-67 as triage marker in HPV-based screening strategies.
Human papillomaviruses (HPVs) are described as ''types'' based on their genome sequences and identified by a number. For example, HPV-6 is associated with genital warts, and HPV-16 with anogenital cancers. The genomes of many HPV types have been reisolated, sequenced and compared to reference ''prototypes'' countless times by laboratories throughout the world. It was found that each HPV type occurs in the form of ''variants'', identified by about 2% nucleotide differences in most genes and 5% in less conserved regions. Less than 100 variants of any HPV type have been detected, a scenario that is very different from the quasi-species formed by many RNA viruses. The variants of each HPV type form phylogenetic trees, and variants from specific branches are often unique to specific ethnic groups. Immigrant populations contain, depending on their respective ethnic origins, mixtures of variants. The absence of HPV genomes intermediate to specific types show that all HPV types existed already when humans became a species. Consequently, humans had always suffered from lesions like anogenital cancer, genital warts and common warts. A growing number of epidemiological, etiological and molecular data suggest that variants of the same HPV type are biologically distinct and may confer differential pathogenic risks. Since the distribution of some variants of HPV-16 and 18 correlates with the distribution of human populations that have an increased risk to develop anogenital cancer, the study of HPV type variation may point to one of the reasons for the higher incidence rates of these lesions in specific cohorts. ' 2005 Wiley-Liss, Inc.Key words: papillomavirus; evolution; epidemiology; etiology Papillomavirus (PV) genomes comprise 8 kb of doublestranded, circular DNA with 8 protein-coding genes (L1 and L2 that encode capsid proteins and E1, E2, E4, E5, E6 and E7 that encode proteins involved in replication, transcription and transformation) and a noncoding, regulatory long control region (LCR). The genomes of PVs change by point mutations, deletions and insertions just like those of their hosts. Mutations occur fortuitously but can become established in a population if there is some mechanism that positively selects for the mutant, or, if they are functionally neutral, by selective expansion of the host population infected with the mutant (genetic drift). DNA genomes change much slower than RNA genomes, because of the proofreading abilities of DNA polymerases. As an example, the most remotely related PV genomes have a nucleotide diversity of about 50%, established during coevolution with their mammalian hosts over millions of years. By contrast, the RNA-based HIV-1 genomes within a single AIDS patient can diverge to a similar extent during a 10-year-infection. PV genomes are further stabilized by the apparent absence of inter-and intra-type recombination. Diversification of PV genomes is also limited by the slow replication of the virus in synchrony with division of the host epithelial cells. Since the replication rate of ep...
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