Electrochemical DNA biosensor for the multianalyte detection of HPV-16 and HPV-18 in oral and cervical lesions

Infection with high-risk human papillomavirus (HPV) is a major risk factor for oral and cervical cancers. In this study, we developed an electrochemical DNA biosensor for detection of HPV-16 and HPV-18, which are the 2 most prevalent genotypes for development of oral and cervical cancers. The assay involves the sandwich hybridization of the HPV target to silica-redox dye reporter probe and capture probe, followed by electrochemical detection. The sensor was found to be highly specific and sensitive, with detection limit of 22 fM for HPV-16 and 20 fM for HPV-18, between the range of 1 fM to 1 µM. Evaluation with oral and cervical samples showed that the biosensor result was consistent with the nested PCR /gel electrophoresis detection. The biosensor assay could be completed within 90 minutes. Due to its simplicity, rapidity and high sensitivity, this biosensor could be used as an alternative method for HPV detection in clinical laboratories. [151 words]

Understanding HPV and cervical screening

Cervical cancer is preventable and curable. Sarah Butler and Yvonne Wilkinson explain how the cervical screening programme has changed from a cytology based test to HPV primary screening Screening for human papillomavirus is now the primary test for cervical screening in England, Wales and Scotland. Cervical screening for those individuals with a cervix routinely occurs every 3 years for those aged 25–49 (24½ in England) and every 5 years for those aged 50–64. Over 99.7% of cervical cancers are caused by human papillomavirus. Cervical cancer is preventable and curable; primary HPV screening can detect early changes in cervical cells allowing for effective monitoring and treatment.

Biochemistry, Not Oncogenes, may Demystify and Defeat Cancer

The presence of mutated genes strongly correlates with the incidence of cancer. Decades of research, however, has not yielded any specific causative gene or set of genes for the vast majority of cancers. The Cancer Genome Atlas program was supposed to provide clarity but it only gave much more data without any accompanying insight into how the disease begins and progresses. It may be time to notice that epidemiological studies consistently show that the environment, not genes, has the principal role in causing cancer. Since carcinogenic chemicals in our food, drink, air and water are the primary culprits, we need to look at the biochemistry of cancer, with a focus on enzymes which invariably facilitate transformations in a cell. In particular, attention should be paid to the rate-limiting enzyme in DNA synthesis, ribonucleotide reductase (RnR) whose activity is tightly linked to tumor growth. Besides circumstantial evidence that cancer is induced at this enzyme’s vulnerable free-radical-containing active-site by various carcinogens, its role in initiating retinoblastoma and HPV-related cervical cancers is well documented. Blocking the activity of malignant RnR is a certain way to arrest cancer.

Mutation Analysis of Radioresistant Early-Stage Cervical Cancer

Radiotherapy is a definitive treatment for early-stage cervical cancer; however, a subset of this disease recurs locally, necessitating establishment of predictive biomarkers and treatment strategies. To address this issue, we performed gene panel-based sequencing of 18 stage IB cervical cancers treated with definitive radiotherapy, including two cases of local recurrence, followed by in vitro and in silico analyses. Simultaneous mutations in KRAS and SMAD4 (KRASmt/SMAD4mt) were detected only in a local recurrence case, indicating potential association of this mutation signature with radioresistance. In isogenic cell-based experiments, a combination of activating KRAS mutation and SMAD4 deficiency led to X-ray resistance, whereas either of these factors alone did not. Analysis of genomic data from 55,308 cancers showed a significant trend toward co-occurrence of mutations in KRAS and SMAD4. Gene Set Enrichment Analysis of the Cancer Cell Line Encyclopedia dataset suggested upregulation of the pathways involved in epithelial mesenchymal transition and inflammatory responses in KRASmt/SMAD4mt cancer cells. Notably, irradiation with therapeutic carbon ions led to robust killing of X-ray-resistant KRASmt/SMAD4mt cancer cells. These data indicate that the KRASmt/SMAD4mt signature is a potential predictor of radioresistance, and that carbon ion radiotherapy is a potential option to treat early-stage cervical cancers with the KRASmt/SMAD4mt signature.

Molecular Pathology of Human Papilloma Virus-Negative Cervical Cancers

Cervical cancer is the fourth most common cancer in women worldwide and is predominantly caused by infection with human papillomavirus (HPV). However, a small subset of cervical cancers tests negative for HPV, including true HPV-independent cancers and false-negative cases. True HPV-negative cancers appear to be more prevalent in certain pathological adenocarcinoma subtypes, such as gastric- and clear-cell-type adenocarcinomas. Moreover, HPV-negative cervical cancers have proven to be a biologically distinct tumor subset that follows a different pathogenetic pathway to HPV-associated cervical cancers. HPV-negative cervical cancers are often diagnosed at an advanced stage with a poor prognosis and are expected to persist in the post-HPV vaccination era; therefore, it is important to understand HPV-negative cancers. In this review, we provide a concise overview of the molecular pathology of HPV-negative cervical cancers, with a focus on their definitions, the potential causes of false-negative HPV tests, and the histology, genetic profiles, and pathogenesis of HPV-negative cancers.

Interval cancer audit and disclosure in cervical screening programmes: An international survey

Background Legal cases involving the National Cervical Screening Programme in Ireland following non-disclosure of an interval cervical cancer audit prompted this first international comparative survey of interval cervical cancer audit. Methods A survey of 22 international population-based cervical screening programmes was conducted, to determine if they undertook audit of invasive cervical cancers. Those countries/regions that perform reviews were asked (i) how the audit was undertaken, including how the reviews were performed and how they controlled for retrospective bias, (ii) how women are informed of the audit process and how their consent is obtained, and (iii) how audit results were disclosed to patients. Results Seventeen countries/regions invited completed the survey (77%); 65% (11/17) have an audit process for interval cervical cancers. Five perform individual patient reviews; three perform programme-wide review, with calculation of interval cancer detection rates; one routinely performs programme-wide review with calculation of interval cancer detection rates and offers individual reviews, and one routinely performs local hospital-level reviews. In the remaining country/region, hospital laboratories audit cancers, with a national audit process for all cervical cancers. Varying methodologies for retrospective cytology review were employed; four include control samples, with a ratio varying from 1:1 to 1:2. Three conduct a blinded review. Most countries/regions do not discuss interval cancer audit with participants and 3/11 (27.3%) inform women when a cervical cancer audit takes place. Disclosure is limited and variable. Conclusion The responses suggest that there is no consistent approach to audit of interval cervical cancers or to disclosure of audit results.

CircCASC15-miR-100-mTOR may Influence the Cervical Cancer Radioresistance

Background Cervical cancer has ranked the top one in gynecological malignancies for incidence. Radioresistance is now becoming a leading reason of recurrence. Methods Our microRNA array data indicated that the miRNA-100 level decreased significantly during radioresistance. In this study, we up-regulated miR-100 in Hela and Siha cells by using miR-100 mimics and observed apoptosis, proliferation, cell cycle and invasion. Results It turned out that with overexpression of miR-100, the cells had more apoptosis and less invasiveness as well as proliferation. It may also influence cell cycle via target gene mTOR, and it deed reduced EMT. To examine the role of miR-100 in radioresistance, there was no significant result showed by BSP.While the circCASC15 has been identified with sponge function according to RNA pull down and ISH. Conclusion The conclusions indicate miR-100 is a tumor suppressor gene and could be a therapeutic target in radio-resistant cervical cancers.

High tumor mutational burden predicts worse prognosis for cervical cancer treated with radiotherapy

Purpose Tumor mutational burden (TMB) is a surrogate biomarker of neo-antigens and high TMB status is associated with favorable response to immune-checkpoint inhibitors (ICIs). This study aimed to elucidate the association between TMB and the outcome of definitive radiotherapy in patients with cervical cancer. Materials and methods TMB and treatment outcome were retrospectively analyzed in patients with newly diagnosed cervical cancer treated with definitive radiotherapy available with somatic mutation data of pre-treatment tumors obtained using a commercially available gene panel. Results The study enrolled 98 patients (median follow-up period, 61 months). The median TMB was 9.5 mutations per megabase (range, 3.0–35.5 mutations per megabase). After dichotomization based on this median value, the 5-year overall survival (OS) for TMB-high patients was significantly worse than that of TMB-low patients (61.1% vs. 82.2%). Multivariate analysis identified high TMB status as a significant prognostic factor for worse OS, along with advanced stage, para-aortic lymph node involvement, and absence of concurrent chemotherapy. Conclusion These data indicate that TMB is a potential prognostic factor for worse survival in patients with cervical cancer treated with definitive radiotherapy, thereby providing a rationale for treatment of TMB-high cervical cancers with a combination of ICIs plus radiotherapy. Secondary abstract This retrospective study of 98 patients demonstrates for the first time that tumor mutational burden (TMB) is an independent prognostic factor for worse overall survival of patients treated with definitive radiotherapy, providing a rationale for treatment of TMB-high cervical cancers with a combination of immune-checkpoint inhibitors plus radiotherapy.