Biomedical subjects

Emmanuel Masongsong

Publications and source records attributed to Emmanuel Masongsong.

4 recordsLinked to original sources

PubMed2006

Human papillomavirus: the burden of infection.

Vaccines for preventing human papillomavirus (HPV) infection are far along in clinical development and testing, and hold great promise for reducing HPV infections and HPV-associated disease. HPV is the most common sexually transmitted infection in the United States, affecting an estimated 75% of the U.S. population. HPV infection is highly prevalent in sexually active adolescents and young adults. Sexual activity is the most important risk factor for infection, with 64% to 82% of sexually active adolescent girls testing positive for HPV. Clinical manifestations of HPV infection include genital warts, cervical intraepithelial neoplasia (CIN), and invasive cervical cancer, all of which cause significant morbidity and, in the case of cervical cancer, mortality. The majority of HPV-associated disease is caused by 4 HPV types: HPV 6 and 11 are responsible for low-grade genital lesions and more than 90% of genital warts, and HPV 16 and 18 both account for approximately 70% of all high-grade CIN or dysplasia and invasive cervical cancer. Although current screening methods have proven effective in reducing cervical cancer incidence and associated mortality, more than 10,000 women are diagnosed annually and 4000 U.S. women die from the disease each year.

Condylomata Acuminata↗

PubMed2006

Smokers at higher risk for undetected antibody for oncogenic human papillomavirus type 16 infection.

OBJECTIVE: To determine the association between tobacco smoking and serologic evidence of human papillomavirus type 16 (HPV16)-specific antibodies among HPV16 DNA-positive women. DESIGN, SETTING, AND PARTICIPANTS: Baseline health history, physical examination, and laboratory data for 205 HPV16 DNA-positive women with no prior cytologic evidence of squamous intraepithelial lesions who were enrolled subsequently in a randomized clinical trial. MAIN OUTCOME MEASURE: HPV16-L1 antibody (anti-HPV16 antibody) detected from serum using RIA or ELISA. RESULTS: Eighty-seven percent (179 of 205) of women tested positive for HPV16 DNA using cervicovaginal swabs or lavage specimens, and 26 women showed similar results using swab specimens of external genitalia alone. HPV16-infected women who reported increasingly greater levels of daily cigarette smoking were less likely to test positive for anti-HPV16 antibodies than nonsmoking women (P = 0.02). Smokers were twice as likely as nonsmokers to test negative for anti-HPV16 antibodies, even after controlling for the effects of other covariates in the analyses (adjusted odds ratio, 0.5; 95% confidence limits, 0.2-0.9). Although Papanicolaou test findings and smoking characteristics were poorly correlated (r(2) = 0.01), women who showed atypical cells of unknown significance or squamous intraepithelial lesion were twice as likely to test anti-HPV16 antibody positive as women who showed normal Papanicolaou tests (adjusted odds ratio, 2.0; 95% confidence limits, 1.1-3.7). CONCLUSION: These data suggest that smoking may influence the long-term risk for cancer by perturbing early immune responses to the virus and may increase the likelihood of persistent infection. Patient education messages should alert women to this additional risk of smoking. A clinical trial of smoking cessation should be explored as a therapeutic intervention for primary HPV16 infection.

Adolescent↗

PubMed2005

Methylation of human papillomavirus genomes in cells of anal epithelia of HIV-infected men.

Intra-anal malignancies disproportionately affect individuals who engage in anal intercourse because of infection with human papillomaviruses (HPVs), with an increased risk attributed to infection with HIV because of a declining immunity against HPVs. Long-term persistence of HPVs suggests yet other mechanisms that determine the clinical outcome, however. Because methylation of HPV DNA represses oncogene expression in cervical samples, we investigated whether this mechanism also occurs in HIV-positive men and studied the methylation of CpG dinucleotides overlapping with the HPV-16 enhancer and promoter in 16 anal samples. Similar to cervical infections, the average methylation frequency was 12.3%, with heterogeneities between clones from different and the same samples. In low-grade anal intraepithelial neoplasia (AIN), methylation was high in CpGs overlapping the viral enhancer but rare in promoter positions, whereas methylation was high in promoter regions in high-grade AIN, especially in samples with a high load of viral genomes. The viral replication origin was never methylated. We also detected de novo methylation at methylated (me) CpA, meCpT, and meCpC dinucleotides. Our study expands the observation and mapping of HPV DNA methylation to anal infections and the HIV-positive patient population. As observed at the cervix, DNA methylation may force HPVs into latency with functional replication but repressed transcription. Escape from this repression is a prerequisite for neoplastic progression; however, methylation resumes because of chromosomal integration of HPV genomes but spares some HPV genomes in each cell that maintain the transformed phenotype. DNA methylation, taken together with virus load, may be useful to diagnose the emergence of a population of tumor cells.

Anal Canal↗

PubMed2004

Cervical cancer screening.

Although primary prevention of human papillomavirus (HPV) infections that are causally associated with invasive cervical cancer may be within our grasp, it is unlikely that these approaches will replace existing cervical cancer screening strategies for many years. Experts agree and data support periodic cytology screening for young-adult women using one of several technologies. Recent analyses of cost-effectiveness suggest that the addition of molecular HPV DNA testing for women aged over 30 years may allow the screening interval to be lengthened to 3 years for most women. Women at high risk for HPV infection and its associated cellular atypias warrant closer monitoring and follow-up. These patients would include organ transplant recipients, women exposed to diethylstilbestrol (DES), and HIV-infected women.

Adult↗