Multiple HPV Infections and Viral Load Association in Persistent Cervical Lesions in Mexican Women.

Persistent high-risk human papillomavirus (HR-HPV) infections play a major role in the development of invasive cervical cancer (CC), and screening for such infections is in many countries the primary method of detecting and preventing CC. HPV typing can be used for triage and risk stratification of women with atypical squamous cells of undetermined significance (ASC-US)/low-grade cervical lesions (LSIL), though the current clinical practice in Mexico is to diagnose CC or its preceding conditions mainly via histology and HR-HPV detection. Additional information regarding these HPV infections, such as viral load and co-infecting agents, might also be useful for diagnosing, predicting, and evaluating the possible consequences of the infection and of its prevention by vaccination. The goal of this follow-up hospital case study was to determine if HPV types, multiple HPV infections, and viral loads were associated with infection persistence and the cervical lesion grade. A total of 294 cervical cytology samples drawn from patients with gynecological alterations were used in this study. HPV types were identified by real-time PCR DNA analysis. A subset of HPV-positive patients was reevaluated to identify persistent infections. We identified HPV types 16, 18, and 39 as the most prevalent. One hundred five of the patients (59%) were infected with more than one type of HPV. The types of HPV associated with multiple HPV infections were 16, 18, and 39. In the follow-up samples, 38% of patients had not cleared the initially detected HPV infection, and these were considered persistent. We found here an association between multiple HPV infections and high viral loads with and infection persistence. Our findings suggest there are benefits in ascertaining viral load and multiple HPV infections status of HR-HPV infections for predicting the risk of persistence, a requirement for developing CC. These findings contribute to our understanding of HPV epidemiology and may allow screening programs to better assess the cancer-developing risks associated with individual HR-HPV infections.

Comparison of Automated and Manual DNA Isolation Methods of Liquid-Based Cytology Samples.

Liquid-based cytology (LBC) has been used as a diagnostic tool for cervical cancer for years and is now being adopted for other gynecological cancers. LBC represents an important challenge to ensure that the process yields representative biospecimens for quality control (QC) of diagnostic procedures. In this study, we compare QC parameters (integrity, yield and purity, and polymerase chain reaction [PCR] amplification) of DNA isolated from LBC (N = 296) using two different nucleic acid isolation methods, manual (n = 233) or automated (n = 63). We also evaluated two different types of cytological brushes for sampling from the cervix. Our results suggest that manual isolation (yield 22.81 ± 1.92 µg) resulted in increased DNA recovery when compared with automated isolation (yield 9.96 ± 1.11 µg) from LBC samples, with a p-value of <0.0003. We estimated that 98% (53/54) of the samples preserved the integrity of DNA and were suitable for standard molecular biology analyses. The ß-globin gene was amplified in 100% (296/296) of the DNA samples by endpoint PCR. We found no significant difference between the performance of the cytological brushes (p value of <0.6711) in a general overview. However, when looking at the results from using each brush individually, the manual isolation method was statistically superior to the automated method. Our work illustrates the impact of good QC of preanalytic conditions, which will be important for the application of LBC for developing early detection methods for gynecological cancers.

The chimpanzee GH locus: composition, organization, and evolution.

In most mammals the growth hormone (GH) locus comprises a single gene expressed primarily in the anterior pituitary gland. However, in higher primates multiple duplications of the GH gene gave rise to a complex locus containing several genes. In man this locus comprises five genes, including GH-N (expressed in pituitary) and four genes expressed in the placenta, but in other species the number and organization of these genes vary. The situation in chimpanzee has been unclear, with suggestions of up to seven GH-like genes. We have re-examined the GH locus in chimpanzee and have deduced the complete sequence. The locus includes five genes apparently organized in a fashion similar to that in human, with two of these genes encoding GH-like proteins, and three encoding chorionic somatomammotropins/placental lactogens (CSHs/PLs). There are notable differences between the human and chimpanzee loci with regard to the expressed proteins, gene regulation, and gene conversion events. In particular, one human gene (hCSH-L) has changed substantially since the chimpanzee/human split, potentially becoming a pseudogene, while the corresponding chimpanzee gene (CSH-A1) has been conserved, giving a product almost identical to the adjacent CSH-A2. Chimpanzee appears to produce two CSHs, with potentially differing biological properties, whereas human produces a single CSH. The pattern of gene conversion in human has been quite different from that in chimpanzee. The region around the GH-N gene in chimpanzee is remarkably polymorphic, unlike the corresponding region in human. The results shed new light on the complex evolution of the GH locus in higher primates.