Cervical cancer screening: which techniques should be used and why?

LncRNA Opa interacting protein 5-antisense RNA 1 (OIP5-AS1) promotes the migration, invasion and epithelial-mesenchymal transition (EMT) through targeting miR-147a/insulin-like growth factor 1 receptor (IGF1R) pathway in cervical cancer tissues and cell model

BACKGROUND

Two factors involved in regulation, long noncoding RNA Opa interacting protein 5-antisense RNA 1 (lncRNA OIP5-AS1) and microRNA-147a, were found in cervical cancer. Therefore, the investigation of the specific regulation of miR-147a by OIP5-AS1 was performed in cervical cancer.

METHOD

The cervical cancer tissues were collected from patients with cervical cancer (n = 50). The expression of OIP5-AS1, miR-147a, proteins in epithelial-mesenchymal transition (EMT) process and insulin-like growth factor 1 receptor (IGF1R) were measured by quantitative real-time polymerase chain reaction (qRT-PCT) or western blotting. Cell motility and the relationship between OIP5-AS1 and miR-147a were detected or analyzed by wound healing test, Transwell assay, dual-luciferase reporter assay, RNA binding protein immunoprecipitation assay or Pearson correlation in OIP5-AS1, or miR-147a over-expressed and/or suppressed cervical cancer cells.

RESULTS

OIP5-AS1 showed the high-expression and miR-147a showed the low-expression in tumor tissues collected from patients with cervical cancer and cell lines Hela, CaSki, Siha, and ME-180. The low-expression of OIP5-AS1 suppressed the motility of Caski cells, as well as up-regulated the level of E-cadherin, which a key protein in EMT. There were targeting sites between miR-147a and OIP5-AS1. OIP5-AS1 induced the down-regulation of miR-147a, so miR-147a was inversely correlated with OIP5-AS1. The down-regulation of miR-147a increased IGF1R and E-cadherin, and these increases were alleviated by OIP5-AS1 knockdown.

CONCLUSION

LncRNA OIP5-AS1 promotes the migration, invasion and EMT of cervical cancer cells via targeting miR-147a/IGF1R pathway.

A lectin-based diagnostic system using circulating antibodies to detect cervical intraepithelial neoplasia and cervical cancer

In the present study, we developed serological strategies using immunoglobulin fractions obtained by protein A chromatography to screen for cervical cancer and cervical intraepithelial neoplasia I (CIN I). The reactivities of the immunoglobulins purified from sera of women with normal cytology, CIN I and cervical cancer were compared in enzyme-linked immunosorbent assays (ELISA) and enzyme-linked lectin assays (ELLAs). To capture the immunoglobulins, ELISAs and ELLAs were performed in protein A immobilized microplates. The reactivity of immunoglobulin in ELISA was in the increasing order normal cytology, CIN I and cervical cancer, while that in ELLAs for detecting fucosylation was in the decreasing order normal cytology, CIN I and cervical cancer. It was confirmed that women with CIN I were distinguishable from women with normal cytology or women with cervical cancer in the ELISA or the ELLA for detecting fucosylation with considerable sensitivity and specificity. Women with cervical cancer were also distinguishable from women with normal cytology with high sensitivity (ELISA: 97%, ELLA: 87%) and specificity (ELISA: 69%, ELLA: 72%). Moreover, the logistic regression model of the ELISA and the ELLA discriminated cervical cancer from normal cytology with 93% sensitivity and 93% specificity. These results indicate that the ELISAs and the ELLAs have great potential as strategies for primary screening of cervical cancer and CIN. It is expected that the ELISA and the ELLA can provide new insights to understand systemic changes of serum immunoglobulins during cervical cancer progression.

Assessment of the Validity and Reproducibility of the Pap Smear in Mexico: Necessity of a Paradigm Shift

BACKGROUND AND AIMS

An assessment was performed of the quality of Pap readings in 19 cytology laboratories (CLs) in Mexico from the Cervical Cancer Screening Program.

METHODS

Nine CLs were affiliated with the Health Ministry (SSA), and ten were affiliated with the Mexican Social Security Institute (IMSS). Two sets of 200 cervical cytology specimens were prepared, one set for each institution. Fourteen percent of the specimens were positive and six were inappropriate for diagnosis (3%). All cervical cytology specimens were processed in the cytopathology laboratory at the General Hospital of Mexico, and histopathology was available for each positive case.

RESULTS

Thirty percent of the SSA reading centers had a sensitivity of at least 80%; however, not one of the ten IMSS laboratories evaluated reached this figure. Some reading centers had a sensitivity <65%, meaning that nearly half of the specimens with a cytology consistent with cervical neoplasm were not identified.

DISCUSSION

Given these results, it is a priority to effect a paradigm shift combining various screening tests to improve adherence to standards and enhanced cost-effectiveness of the early detection of cervicouterine cancer (CC) in Mexico.

Human papillomavirus genotype distributions: implications for vaccination and cancer screening in the United States

BACKGROUND

Limited data are available describing human papillomavirus (HPV) genotype distributions in cervical cancer in the United States. Such studies are needed to predict how HPV vaccination and HPV-based screening will influence cervical cancer prevention.

METHODS

We used the New Mexico Surveillance, Epidemiology, and End Results Registry to ascertain cases of in situ (n = 1213) and invasive (n = 808) cervical cancer diagnosed during 1985-1999 and 1980-1999, respectively, in the state of New Mexico. HPV genotyping was performed using two polymerase chain reaction-based methods on paraffin-embedded tissues from in situ and invasive cancers and on cervical Papanicolaou test specimen from control subjects (ie, women aged 18-40 years attending clinics for routine cervical screening [n = 4007]). Relative risks for cervical cancer were estimated, and factors associated with age at cancer diagnosis and the prevalence of HPV genotypes in cancers were examined.

RESULTS

The most common HPV genotypes detected in invasive cancers were HPV type 16 (HPV16, 53.2%), HPV18 (13.1%), and HPV45 (6.1%) and those in in situ cancers were HPV16 (56.3%), HPV31 (12.6%), and HPV33 (8.0%). Invasive cancer case subjects who were positive for HPV16 or 18 were diagnosed at younger ages than those who were positive for other carcinogenic HPV genotypes (mean age at diagnosis: 48.1 [95% confidence interval {CI} = 46.6 to 49.6 years], 45.9 [95% CI = 42.9 to 49.0 years], and 52.3 years [95% CI = 50.0 to 54.6 years], respectively). The proportion of HPV16-positive in situ and invasive cancers, but not of HPV18-positive cancers, declined with more recent calendar year of diagnosis, whereas the proportion positive for carcinogenic HPV genotypes other than HPV18 increased.

CONCLUSIONS

HPV16 and 18 caused the majority of invasive cervical cancer in this population sample of US women, but the proportion attributable to HPV16 declined over the last 20 years. The age at diagnosis of HPV16- and HPV18-related cancers was 5 years earlier than that of cancers caused by carcinogenic HPV genotypes other than HPV16 and 18, suggesting that the age at initiation of cervical screening could be delayed in HPV-vaccinated populations.

Human papillomavirus vaccine and cervical cancer prevention

Cervical cancer is one of the most common types of cancer in women worldwide, with the highest rates observed in underdeveloped countries. In the last decades, its incidence has decreased after the implementation of screening programs, mainly in developed countries. Infection with high-risk oncogenic HPV is associated with precancerous lesions and cervical cancer. Advances in the understanding of the role of HPV in the etiology of high-grade cervical lesions (CIN 2/3) and cervical cancer have led to the development, evaluation and recommendation of two prophylactic HPV vaccines. This review article provides a summary of the studies related with their development and efficacy.

Advances in primary and secondary interventions for cervical cancer: human papillomavirus prophylactic vaccines and testing

Cytologic screening has greatly reduced the incidence of invasive cervical cancer in many industrialized nations. State-of-the-art cervical cancer prevention is costly, however, and includes cytologic screening at repeat intervals, confirmation of abnormalities by colposcopic biopsy, and treatment of precancerous lesions. In resource-limited settings, accessibility to prevention programs for cervical cancer is often poor, or such programs are simply unavailable or inadequately supported. This disease, therefore, remains a leading form of cancer among women living in low-resource regions, and over 250,000 women worldwide die from cervical cancer each year. Persistent cervical infection with one of approximately 15 carcinogenic human papillomavirus (HPV) types causes virtually all invasive cervical cancer and its precursor abnormalities, which can be detected by cytologic screening. Genital HPV infections are primarily transmitted via sexual intercourse. One promising prophylactic HPV vaccine is available and others continue in development as primary cervical cancer prevention strategies in younger women. As secondary interventions, HPV tests are simultaneously evolving for use in cervical cancer screening programs, including routine screening of older women. HPV testing is more sensitive and reproducible than cytology with colposcopy for the detection of cervical precancer and cancer. This article presents current advances and perspectives on HPV vaccines and HPV testing.

Evolution of the evidence-based Papanicolaou smear

Cervical cancer rates have decreased over the past century, but rates have remained relatively constant during the last decade. Evidence-based management of the abnormal Papanicolaou (Pap) smear and the use of additional testing at the time of the Pap smear are discussed in light of the current evidence. Also explored in-depth is the evidence base for Papanicolaou smear collection and retrieval methods, especially as it relates to their influence on the validity of the smear results. In addition, issues that need to be considered by the clinician, including the use of colposcopy, especially in light of health service implications such as the need for adequately trained personnel, increased clinical visit time, and increased cost are presented.

New technologies in cervical cancer precursor detection

The current literature reflects three routes toward improving cervical cancer screening. The first is to improve the test qualities of cytology-based screening. The use of liquid-based cytology and computerized analysis of Papanicolaou tests are examples of attempts at this approach. Secondly, through various combinations of parallel or sequential tests, either the sensitivity or the specificity of a given test could be improved depending on the tests chosen and the order in which they were performed (eg, Papanicolaou test followed by human papillomavirus [HPV] or vice versa). Several excellent studies have been published this year on the use of HPV DNA testing as a primary screening modality and as an adjunct to the triage of mildly abnormal cytologic findings. The recent literature also reflects increasing interest in visual inspection of the cervix and self-collected samples for HPV testing as an equally effective and viable alternative to cytology in low-resource settings. A third possibility is to make use of advances in digital and spectroscopic techniques. In these cost-conscious times, a significant number of articles address the cost-effectiveness of these technologies and the real value of cervical cancer screening. This article reviews the current literature concerning both the advent of new cervical cancer screening technologies and the rediscovery of old ones.