Cervical Cancer: Screening and Prevention of Invasive Disease

Protection against heterologous human papillomavirus challenge by a synthetic lipopeptide vaccine containing a broadly cross-neutralizing epitope of L2

Persistent infection with the high-risk subset of genitotropic human papillomavirus (HPV) genotypes is a necessary cause of cervical cancer. Given the global burden of cervical cancer, a low-cost, broadly protective vaccine is needed. RG-1 is a cross-neutralizing and protective monoclonal antibody that recognizes residues 17-36 of HPV16 minor capsid protein L2. Because this epitope is highly conserved in divergent HPV types, we determined whether vaccination with HPV16 L2 17-36 peptide is broadly protective. The peptide was administered to BALB/c mice three times at monthly intervals, either alone or in the context of a synthetic lipopeptide vaccine candidate (P25-P2C-HPV) produced by linkage of the HPV peptide with a broadly recognized T helper epitope (P25) and the Toll-like receptor-2 (TLR2) ligand dipalmitoyl-S-glyceryl cysteine (P2C). In contrast to vaccination with the L2 17-36 peptide or P25-P2C alone, a potent L2-specific antibody response was generated to the P25-P2C-HPV lipopeptide when delivered either s.c. or intranasally. Sera from mice vaccinated with the P25-P2C-HPV lipopeptide neutralized not only HPV16 pseudovirions but also other evolutionarily divergent oncogenic genital (HPV18, HPV45) and cutaneous (HPV5, BPV1) types. The L2-specific antibody response depended on MHC class II, CD40, and MyD88 signaling. Additionally, vaccination with the P25-P2C-HPV lipopeptide protected mice from homologous challenge with HPV16 pseudovirions at cutaneous and genital sites and heterologous challenge with HPV45 pseudovirions. If provided in the appropriate context, therefore, HPV16 L2 17-36 might be used in a totally synthetic cross-protective HPV vaccine.

Prevalence and correlates of cervical cancer screening among injection drug users

OBJECTIVE

Access to cervical cancer screening may be lower among lower income and socially disadvantaged populations. However, few studies have specifically examined factors associated with cervical cancer screening among socially marginalized populations, especially in settings with free health care systems.

METHODS

The present study was conducted to examine the prevalence and correlates of cervical cancer screening among injection drug users. We examined rates of Papanicolaou (Pap) smear testing among female participants in the Vancouver Injection Drug Users Study (VIDUS). Univariate and logistic regression analyses were used to evaluate factors associated with cervical cancer screening.

RESULTS

During the period from December 2004 to May 2005, 297 female injection drug users were seen. In logistic regression analyses, age (adjusted odds ratio [AOR]=0.70; 95% confidence intervals [CI] 0.53, 0.92, P=0.010), HIV infection (AOR=2.46; 95% CI 1.41,4.26, P=0.001), hepatitis C infection (AOR=0.25; 95% CI 0.09,0.71, P=0.010), and having visited a family physician in the prior six months (OR=3.10; 95% CI 1.58, 6.07, P=0.001) were independently associated with recent cervical cancer screening.

CONCLUSIONS

After adjustment for regular physician visits, HIV infection was associated with elevated rates of cervical screening. This is reassuring, given the elevated risk of cervical cancer among this population. Interventions may be required to improve uptake of screening among older injection drug users and drug users infected with hepatitis C.

Cervical cancer screening program of Paraná: Cytohistological correlation results after five years

Since its inception in November 1997, the Cervical Cancer Screening Program of Paraná (CCSPP), Brazil, has resulted in the cytological screening of 2,244,158 women, the coverage of the female population increasing from 43% to 86%. One thousand six hundred one cases screened by cytology, submitted to colposcopy, and subjected to treatment were selected. Cytopathological results were compared with those obtained on the basis of histological analyses of the loop electrical excision procedure specimens, and were subjected to statistical analyses. The data obtained were then compared with cytohistological correlation results from the first year of the program. Considering the exact correlation between cytological and histological diagnoses, the correlation index increased from 53.34% in the first year to 67.3% at the end of 5 yr of the program. Variations that occurred in each diagnostic category are discussed. This study demonstrates a significant improvement in the concordance between cytological and histological results for the 5-yr period compared with the first year of the CCSPP.

Predictors of regular Pap smears among Korean-American women

BACKGROUND

Many Korean-American women (KAW) are unaware of the importance of regular cancer screening. This research estimates rates and examines predictors of regular cervical cancer screening among KAW.

METHODS

Face-to-face surveys were conducted with 459 KAW residing in Maryland. Study participants were recruited through Korean churches and senior housing.

RESULTS

Thirty-nine percent of women had regular Pap smears. Regular Pap smear rates varied with age, with women 65 years and older least likely to have regular Pap smears. In multiple logistic regression, the strongest correlate of regular Pap smear was knowledge of guidelines. Physician recommendation, having health insurance, and having friends or family members receiving Pap smears were also important facilitators. Spoken English proficiency interacted with education for an outcome; women with a low level of education and low English proficiency had lower rates of Pap smears than those who had a high level of education and high proficiency. The most frequently given reason for lack of a regular Pap smear was a belief that screening was unnecessary if a woman had no symptoms of cervical cancer.

CONCLUSIONS

Strategies for education on screening guidelines, along with physician referrals, should be implemented. Culturally appropriate educational programs about cervical cancer screening should be developed for less educated and less acculturated immigrant women.

Common cancers--genetics, origin, prevention, screening: Parts I and II

Carcinogenesis is a stepwise process that occurs through mutations of cancer-related genes. Five or more genes must be mutated before malignant transformation occurs in most adult cancers; in some childhood cancers as few as two mutated genes may be sufficient. A rare inherited mutation of a critical gene may predestine cancer to occur in one or more sites. This germline mutation is present in virtually every cell in the body, except half of the germ cells, which do not contain the mutated gene in their haploid chromosome set. These and other genes have been used to piece together a puzzle of regulatory systems that govern cell division and proliferation, as well as apoptosis or programmed cell death. Mutations of these genes result not only in increased cell proliferation but also in diminished cell death. Most genetic changes that occur during carcinogenesis are not inherited or germline. They are acquired after birth and are called somatic mutations. A somatic mutation affects only the mutated cell and its progeny. Each time a cell divides, there is a chance of somatic mutation, and therefore there always is a low, background risk for cancer and other malignant lesions. A far more prevalent cause of cancer-related death in the United States is environmental exposure. Such exposure causes somatic mutations of cancer-related genes through direct damage to DNA or through alteration of proliferation or cell death, which enhances the baseline risk for mutation. As carcinogenesis becomes understood, interventions may be designed that selectively interfere in important steps. Screening for cancer is based on the premise that one can treat a patient for a cancer that has not spread from its primary site. Nevertheless, cancer screening is controversial and often confusing. Issues of costs, risks versus benefits, physical time and effort, and patient compliance all affect the clinician's view of screening, often to the extent that the true value of this approach to cancer control is underappreciated and underutilized. A clinician should consider the following questions when assessing the priority, scope, and intensity of cancer screening. Is the cancer an important public health problem? Can preclinical stages be detected and cured? Are effective screening tests available? Are the tests feasible and acceptable? Have screening programs reduced cancer-specific mortality? Is the screening program cost effective? Is screening generally recommended? There is clear-cut evidence of benefit from screening for cancer of the cervix, breast, colon and rectum, and skin and some specific genetic syndromes. Evidence of survival benefit from screening for prostate cancer is lacking, although prostate specific antigen screening is widely used. Screening for lung and ovarian cancer is ineffective.