Screening for precancerous anal lesions linked to human papillomaviruses: French recommendations for clinical practice

In France, about 2000 new cases of anal cancer are diagnosed annually. Squamous cell carcinoma is the most common histological type, mostly occurring secondary to persistent HPV16 infection. Invasive cancer is preceded by precancerous lesions. In addition to patients with a personal history of precancerous lesions and anal cancer, three groups are at very high risk of anal cancer: (i) men who have sex with men and are living with HIV, (ii) women with a history of high-grade squamous intraepithelial lesions (HSILs) or vulvar HPV cancer, and (iii) women who received a solid organ transplant more than 10 years ago. The purpose of screening is to detect HSILs so that they can be treated, thereby reducing the risk of progression to cancer. All patients with symptoms should undergo a proctological examination including standard anoscopy. For asymptomatic patients at risk, an initial HPV16 test makes it possible to target patients at risk of HSILs likely to progress to cancer. Anal cytology is a sensitive test for HSIL detection. Its sensitivity is greater than 80% and exceeds that of proctological examination with standard anoscopy. It is indicated in the event of a positive HPV16 test. In the presence of cytological abnormalities and/or lesions and a suspicion of dysplasia on clinical examination, high-resolution anoscopy is indicated. Performance is superior to that of proctological examination with standard anoscopy. However, this technique is not widely available, which limits its use. If high-resolution anoscopy is not possible, screening by a standard proctological examination is an alternative. There is a need to develop high-resolution anoscopy and triage tests and to evaluate screening strategies.

BRCA1-BARD1 combines multiple chromatin recognition modules to bridge nascent nucleosomes

Chromatin association of the BRCA1-BARD1 heterodimer is critical to promote homologous recombination repair of DNA double-strand breaks (DSBs) in S/G2. How the BRCA1-BARD1 complex interacts with chromatin that contains both damage induced histone H2A ubiquitin and inhibitory H4K20 methylation is not fully understood. We characterised BRCA1-BARD1 binding and enzymatic activity to an array of mono- and di-nucleosome substrates using biochemical, structural and single molecule imaging approaches. We found that the BRCA1-BARD1 complex preferentially interacts and modifies di-nucleosomes over mono-nucleosomes, allowing integration of H2A Lys-15 ubiquitylation signals with other chromatin modifications and features. Using high speed- atomic force microscopy (HS-AFM) to monitor how the BRCA1-BARD1 complex recognises chromatin in real time, we saw a highly dynamic complex that bridges two nucleosomes and associates with the DNA linker region. Bridging is aided by multivalent cross-nucleosome interactions that enhance BRCA1-BARD1 E3 ubiquitin ligase catalytic activity. Multivalent interactions across nucleosomes explain how BRCA1-BARD1 can recognise chromatin that retains partial di-methylation at H4 Lys-20 (H4K20me2), a parental histone mark that blocks BRCA1-BARD1 interaction with nucleosomes, to promote its enzymatic and DNA repair activities.

BARD1 reads H2A lysine 15 ubiquitination to direct homologous recombination

Protein ubiquitination at sites of DNA double-strand breaks (DSBs) by RNF168 recruits BRCA1 and 53BP11,2, which are mediators of the homologous recombination and non-homologous end joining DSB repair pathways, respectively3. Non-homologous end joining relies on 53BP1 binding directly to ubiquitinated lysine 15 on H2A-type histones (H2AK15ub)4,5 (which is an RNF168-dependent modification6), but how RNF168 promotes BRCA1 recruitment and function remains unclear. Here we identify a tandem BRCT-domain-associated ubiquitin-dependent recruitment motif (BUDR) in BRCA1-associated RING domain protein 1 (BARD1) (the obligate partner protein of BRCA1) that, by engaging H2AK15ub, recruits BRCA1 to DSBs. Disruption of the BUDR of BARD1 compromises homologous recombination and renders cells hypersensitive to PARP inhibition and cisplatin. We further show that BARD1 binds nucleosomes through multivalent interactions: coordinated binding of H2AK15ub and unmethylated H4 lysine 20 by its adjacent BUDR and ankyrin repeat domains, respectively, provides high-affinity recognition of DNA lesions in replicated chromatin and promotes the homologous recombination activities of the BRCA1-BARD1 complex. Finally, our genetic epistasis experiments confirm that the need for BARD1 chromatin-binding activities can be entirely relieved upon deletion of RNF168 or 53BP1. Thus, our results demonstrate that by sensing DNA-damage-dependent and post-replication histone post-translation modification states, BRCA1-BARD1 complexes coordinate the antagonization of the 53BP1 pathway with promotion of homologous recombination, establishing a simple paradigm for the governance of the choice of DSB repair pathway.

Deep neural network trained on surface ECG improves diagnostic accuracy of prior myocardial infarction over Q wave analysis

Background

Detection of prior myocardial infarction (MI) may inform arrhythmia treatment and prognosis, yet cardiac imaging is resource intensive. ECG Q-wave analysis is quick and inexpensive but has poor accuracy for assessing prior MI.

Purpose

To evaluate the ability of a deep neural network (DNN) trained on the surface ECG to identify patients with prior MI.

Methods

We assessed 608 well-characterized patients (61.4±14.5 years, 31.2% female) at 2 academic centers. From one 12-lead ECG, median beats were calculated in 3 orthogonal planes (X, Y, Z; Fig. 1A) and used to train a DNN to identify a history of prior MI. Accuracy was compared to manual assessment of pathologic Q waves, defined as a deflection >25% of the subsequent R wave, >40ms in width, and >0.2mV amplitude in 1 of 3 ECG planes.

Results

Of 608 patients, 175 had history of MI (28.7%). The DNN outperformed the accuracy of pathologic Q waves. In training, DNN converged to >98% accuracy and in testing, its accuracy was 71±5% (Fig. 1B) (k=5-fold cross validation). This outperformed the 62% accuracy of pathologic Q waves in this study (red dotted line, Fig. 1B). In the validation cohort, DNN provided an area under the receiver operating characteristics curve of 0.730 (Fig. 1C).

Conclusion

Deep learning of a 12-lead ECG can identify features of prior myocardial injury more accurately than Q-wave analysis. In attempting to improve these results further, studies should explain what inputs weighted DNN decisions, and identify those that reflect abnormalities detectable clinically or on imaging.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): NIH NRSA F32

Comparing machine learning approaches to identify myocardial scar from the ECG

Background

Detection of myocardial infarction (MI) traditionally requires ECG Q waves, which have poor sensitivity, or imaging, which is time consuming. We hypothesized that machine learning (ML) of the ECG could identify prior MI, but its accuracy may depend highly upon the architecture and parameters chosen.

Purpose

To compare ML architectures that predict prior MI from the ECG.

Methods

We curated ECGs in 608 patients seen in cardiology clinics at 2 centers. We transformed 12-lead ECGs to median beats in Frank (X, Y, Z) planes (fig. A). We tested 3 architectures: a 1D deep neural network (DNN), a 3D neural network, and a support vector machine (SVM). The 1D DNN used only temporal convolutions (fig B) while the 3D DNN uses a spatial convolution (fig C) prior to the fully-connected layer (fig. C). Predictive accuracy for history of MI was compared for all architectures (fig. D).

Results

Patients (61.4±14.5 years, 31.2% female) had a 28.7% (175/608) prevalence of prior MI. Optimized SVM of 6 features provided accuracy of 66.1% for identifying prior MI, similar to ECG Q wave analysis. 1D DDN had accuracy of 63.6% with an area under curve (AUC) of 0.625. 3D DNN outperformed 1D DNN and SVM, providing an accuracy of 71±5% (using k=5-fold cross validation), with an AUC of 0.730.

Conclusion

ECG machine learning can identify prior MI better than Q wave analysis, but is sensitive to technical parameters and specific computational architecture. It is important to develop a framework to enable robust comparisons of different ML studies and future refinements.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health - United States

PALB2 chromatin recruitment restores homologous recombination in BRCA1-deficient cells depleted of 53BP1

Loss of functional BRCA1 protein leads to defects in DNA double-strand break (DSB) repair by homologous recombination (HR) and renders cells hypersensitive to poly (ADP-ribose) polymerase (PARP) inhibitors used to treat BRCA1/2-deficient cancers. However, upon chronic treatment of BRCA1-mutant cells with PARP inhibitors, resistant clones can arise via several mechanisms, including loss of 53BP1 or its downstream co-factors. Defects in the 53BP1 axis partially restore the ability of a BRCA1-deficient cell to form RAD51 filaments at resected DSBs in a PALB2- and BRCA2-dependent manner, and thereby repair DSBs by HR. Here we show that depleting 53BP1 in BRCA1-null cells restores PALB2 accrual at resected DSBs. Moreover, we demonstrate that PALB2 DSB recruitment in BRCA1/53BP1-deficient cells is mediated by an interaction between PALB2's chromatin associated motif (ChAM) and the nucleosome acidic patch region, which in 53BP1-expressing cells is bound by 53BP1's ubiquitin-directed recruitment (UDR) domain.

Knowledge, Attitudes and Practices of Non-Consultant Hospital Doctors In The Immediate Post-Fall Period

Aim The aim of this study is to determine the knowledge, attitudes and practices of Non-Consultant Hospital Doctors (NCHDs) in the immediate post-fall period. Methods A survey study design was employed using an online questionnaire of all NCHDs in SVUH comprising 15 questions that blend dichotomous, multiple choice, scaled and open-ended questions to determine knowledge, attitudes and practices of NCHDs across three constructs; injury management, falls prevention and fracture prevention. Descriptive statistics was used to analyse data. Results There was a 40% response rate (n=105). The respondents reported dissatisfaction with their standard of falls assessment training (mean 4/10). Between 60-70% of NCHDs do not routinely determine hip trauma, joint tenderness, syncope, use of anti-coagulants, visual symptoms, amnesia or vomiting. Half of respondents (n=57) rarely or never rationalised medications. The main reasons for this are lack of knowledge of alternatives (63%), time constraints (65%), benefits outweighing the risks (80%) and reluctance to interfere with care of another medical team (86%). Only 9% always consider a bone health review. Discussion A targeted education programme in the areas of hip assessment, neurological assessment, syncope management, medication rationalisation and bone protection is warranted.

Lower gastrointestinal symptoms are prevalent among individuals colonoscoped within the Bowel Cancer Screening Programme

AIM

The National Health Service Bowel Cancer Screening Programme (BCSP) aims to detect earlier stage cancer in asymptomatic individuals. Early experience suggested that many participants had lower gastrointestinal symptoms before screening. The study evaluated the prevalence of lower gastrointestinal symptoms and consultation behaviour among individuals undergoing colonoscopy at the South of Tyne BCSP Centre.

METHOD

Data were collected on all undergoing clinic assessment and colonoscopy. Symptoms were categorized as altered bowel habit (ABH), rectal bleeding (RB), abdominal pain (AP) and unexplained weight loss (UWL).

RESULTS

Symptoms were present in 65.1% (492/756) of subjects, 64.4% (431/669) of those with a non-cancer diagnosis and 70.1% (61/87) of those with cancer. Among those with a non-cancer diagnosis, symptoms were ABH in 52% (224/431), RB in 81.4% (351/431), AP in 15.3% (66/431) and UWL in 3.0% (13/431). In those with cancer symptoms they were ABH in 33.3% (29/87), RB in 55.2% (48/87) and AP in 11.5% (10/87). There was no significant difference in the prevalence of symptoms in those with a cancer or non-cancer diagnosis. A total of 34.2% (157/459) of individuals with symptoms had consulted their general practitioner, 28.1% (16/57) of those with cancer and 35.1% (141/402) without.

CONCLUSION

A large proportion of individuals colonoscoped in the BCSP reported symptoms predating screening. Their prevalence did not differ significantly between cancer and non-cancer diagnoses. The majority had not consulted their general practitioner. Health promotion regarding the importance of lower gastrointestinal symptoms and a risk assessment tool to help select those needing urgent specialist assessment are required.

Differences in the risk of cervical cancer and human papillomavirus infection by education level

BACKGROUND

Cervical cancer risk is associated with low education even in an unscreened population, but it is not clear whether human papillomavirus (HPV) infection follows the same pattern.

METHODS

Two large multicentric studies (case-control studies of cervical cancer and HPV prevalence survey) including nearly 20 000 women. GP5+/GP6+ PCR was used to detect HPV.

RESULTS

Education level was consistently associated with cervical cancer risk (odds ratio (OR) for 0 and >5 years vs 1-5 years=1.50, 95% confidence interval (CI): 1.25-1.80 and 0.69, 95% CI: 0.57-0.82, respectively, P for trend <0.0001). In contrast, no association emerged between education level and HPV infection in either of the two IARC studies. A majority of the women studied had never had a Pap smear. The association between low education level and cervical cancer was most strongly attenuated by adjustment for age at first sexual intercourse and first pregnancy. Parity and screening history (but not lifetime number of sexual partners, husband's extramarital sexual relationships, and smoking) also seemed to be important confounding factors.

CONCLUSION

The excess of cervical cancer found in women with a low socio-economic status seems, therefore, not to be explained by a concomitant excess of HPV prevalence, but rather by early events in a woman's sexually active life that may modify the cancer-causing potential of HPV infection.

Different cervical cancer screening approaches in a Chinese multicentre study

To evaluate alternative cervical cancer screening methods, digital colposcopy and collection of cervical exfoliated cells for liquid-based cytology (LBC) and hybrid capture 2 (HC2) testing were performed among 2562 women aged 15–59 years in three study sites in the People's Republic of China (rural Shanxi province, Shenyang city in Liaoning province and Shenzhen city in Guangdong province). Visual inspection with acetic acid (VIA) was also evaluated independently from colposcopy. A total of 74 cases of histologically confirmed cervical intraepithelial neoplasia grade 2 or worse (CIN2+) were identified, and 16 CIN2+ cases were imputed among unbiopsied women to correct for verification bias. Corrected sensitivity for CIN2+ was 37% for VIA, 54% for colposcopy, 87% for LBC with a threshold of atypical cells of undetermined significance (LBC⩾ASCUS), 90% for HC2, 84% for LBC using HC2 to triage ASCUS and 96% for positivity to LBC⩾ASCUS or HC2. For VIA, sensitivity was much lower among women ⩾40 years (12%) than those aged ⩽39 years (50%). Specificity varied from 77% for positivity to LBC⩾ASCUS or HC2, up to 94% for LBC using HC2 to triage ASCUS. In conclusion, LBC, HC2 and their combinations performed well, whereas VIA missed a majority of CIN2+, particularly in older women. Digital colposcopy performed better than VIA, but still missed nearly half of CIN2+ in this study.

Health and economic impact of HPV 16 and 18 vaccination and cervical cancer screening in India

Cervical cancer is a leading cause of cancer death among women in low-income countries, with approximately 25% of cases worldwide occurring in India. We estimated the potential health and economic impact of different cervical cancer prevention strategies. After empirically calibrating a cervical cancer model to country-specific epidemiologic data, we projected cancer incidence, life expectancy, and lifetime costs (I$2005), and calculated incremental cost-effectiveness ratios (I$/YLS) for the following strategies: pre-adolescent vaccination of girls before age 12, screening of women over age 30, and combined vaccination and screening. Screening differed by test (cytology, visual inspection, HPV DNA testing), number of clinical visits (1, 2 or 3), frequency (1 x , 2 x , 3 x per lifetime), and age range (35-45). Vaccine efficacy, coverage, and costs were varied in sensitivity analyses. Assuming 70% coverage, mean reduction in lifetime cancer risk was 44% (range, 28-57%) with HPV 16,18 vaccination alone, and 21-33% with screening three times per lifetime. Combining vaccination and screening three times per lifetime provided a mean reduction of 56% (vaccination plus 3-visit conventional cytology) to 63% (vaccination plus 2-visit HPV DNA testing). At a cost per vaccinated girl of I$10 (per dose cost of $2), pre-adolescent vaccination followed by screening three times per lifetime using either VIA or HPV DNA testing, would be considered cost-effective using the country's per capita gross domestic product (I$3452) as a threshold. In India, if high coverage of pre-adolescent girls with a low-cost HPV vaccine that provides long-term protection is achievable, vaccination followed by screening three times per lifetime is expected to reduce cancer deaths by half, and be cost-effective.

Cervical cancer screening programmes and policies in 18 European countries

A questionnaire survey was conducted by the Epidemiology Working Group of the European Cervical Cancer Screening Network, and the International Agency for Research on Cancer, IARC, between August and December 2003 in 35 centres in 20 European countries with reliable cervical cancer incidence and/or mortality data in databanks held at IARC and WHO. The questionnaire was completed by 28 centres from 20 countries. The final tables included information on 25 centres from 18 countries. Six countries had started screening in the 1960s, whereas 10 countries or regions had started at least a pilot programme by 2003. There were six invitational and nine partially invitational programmes, the rest employing opportunistic screening only. Recommended lifetime number of smears varied from seven to more than 50. Coverage of smear test within the recommended screening interval (usually 3 or 5 years) was above 80% in three countries. Screening registration took place in 13 programmes. Eight programmes reported the rates of screen-detected cervical cancers and precursor lesions. There was wide variation in the CIN3 detection rates. International guidelines and quality assurance protocols are useful for monitoring and evaluating screening programmes systematically. Our survey indicated that the recommendations as currently given are met in only few European countries. Health authorities need to consider stronger measures and incentives than those laid out in the current set of recommendations.