Targeting DNA Damage Response and Replication Stress in Pancreatic Cancer.

BACKGROUND & AIMS: Continuing recalcitrance to therapy cements pancreatic cancer (PC) as the most lethal malignancy, which is set to become the second leading cause of cancer death in our society. The study aim was to investigate the association between DNA damage response (DDR), replication stress, and novel therapeutic response in PC to develop a biomarker-driven therapeutic strategy targeting DDR and replication stress in PC. METHODS: We interrogated the transcriptome, genome, proteome, and functional characteristics of 61 novel PC patient-derived cell lines to define novel therapeutic strategies targeting DDR and replication stress. Validation was done in patient-derived xenografts and human PC organoids. RESULTS: Patient-derived cell lines faithfully recapitulate the epithelial component of pancreatic tumors, including previously described molecular subtypes. Biomarkers of DDR deficiency, including a novel signature of homologous recombination deficiency, cosegregates with response to platinum (P < .001) and PARP inhibitor therapy (P < .001) in vitro and in vivo. We generated a novel signature of replication stress that predicts response to ATR (P < .018) and WEE1 inhibitor (P < .029) treatment in both cell lines and human PC organoids. Replication stress was enriched in the squamous subtype of PC (P < .001) but was not associated with DDR deficiency. CONCLUSIONS: Replication stress and DDR deficiency are independent of each other, creating opportunities for therapy in DDR-proficient PC and after platinum therapy.

Mental health of children with vision impairment at 11 years of age.

AIM: The purpose of the study was to compare the risk of psychiatric disturbance among sighted and vision-impaired children aged 11 years. METHOD: Scores from the parent and teacher versions of the Strengths and Difficulties Questionnaire (SDQ) were used to compare sighted children with: vision-impaired children; vision-impaired children with no other reported disabilities or special educational needs; and children with vision impairment and additional disabilities or special educational needs. Logistic regression was used to measure the associations between the independent variables and SDQ scores, and to test for significance of the observed differences. RESULTS: Both parents and teachers scored vision-impaired children significantly higher on the SDQ compared with sighted children (p≤0.000) and a significantly higher proportion of the vision-impaired children had SDQ scores in the abnormal range (p≤0.000). Children with vision impairment and other disabilities or special educational needs were rated as being at greatest risk of psychiatric disorder by both parents (30%) and teachers (22%). INTERPRETATION: Vision impairment among children as young as 11 years of age is associated with an increased risk of psychiatric disorder.

Elucidating Prostate Cancer Behaviour During Treatment via Low-pass Whole-genome Sequencing of Circulating Tumour DNA.

BACKGROUND: Better blood tests to elucidate the behaviour of metastatic castration-resistant prostate cancer (mCRPC) are urgently needed to drive therapeutic decisions. Plasma cell-free DNA (cfDNA) comprises normal and circulating tumour DNA (ctDNA). Low-pass whole-genome sequencing (lpWGS) of ctDNA can provide information on mCRPC behaviour. OBJECTIVE: To validate and clinically qualify plasma lpWGS for mCRPC. DESIGN, SETTING, AND PARTICIPANTS: Plasma lpWGS data were obtained for mCRPC patients consenting to optional substudies of two prospective phase 3 trials (FIRSTANA and PROSELICA). In FIRSTANA, chemotherapy-naïve patients were randomised to treatment with docetaxel (75 mg/m2) or cabazitaxel (20 or 25 mg/m2). In PROSELICA, patients previously treated with docetaxel were randomised to 20 or 25 mg/m2 cabazitaxel. lpWGS data were generated from 540 samples from 188 mCRPC patients acquired at four different time points (screening, cycle 1, cycle 4, and end of study). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: lpWGS data for ctDNA were evaluated for prognostic, response, and tumour genomic measures. Associations with response and survival data were determined for tumour fraction. Genomic biomarkers including large-scale transition (LST) scores were explored in the context of prior treatments. RESULTS AND LIMITATIONS: Plasma tumour fraction was prognostic for overall survival in univariable and stratified multivariable analyses (hazard ratio 1.75, 95% confidence interval 1.08-2.85; p = 0.024) and offered added value compared to existing biomarkers (C index 0.722 vs 0.709; p = 0.021). Longitudinal changes were associated with drug response. PROSELICA samples were enriched for LSTs (p = 0.029) indicating genomic instability, and this enrichment was associated with prior abiraterone and enzalutamide treatment but not taxane or radiation therapy. Higher LSTs were correlated with losses of RB1/RNASEH2B, independent of BRCA2 loss. CONCLUSIONS: Plasma lpWGS of ctDNA describes CRPC behaviour, providing prognostic and response data of clinical relevance. The added prognostic value of the ctDNA fraction over established biomarkers should be studied further. PATIENT SUMMARY: We studied tumour DNA in blood samples from patients with prostate cancer. We found that levels of tumour DNA in blood were indicative of disease prognosis, and that changes after treatment could be detected. We also observed a "genetic scar" in the results that was associated with certain previous treatments. This test allows an assessment of tumour activity that can complement existing tests, offer insights into drug response, and detect clinically relevant genetic changes.

Hypertension treatment and control rates: chart review in an academic family medicine clinic.

OBJECTIVE: To characterize hypertension management in an academic family medicine clinic. DESIGN: Cross-sectional chart review. SETTING: Academic family medicine clinic in Edmonton, Alta. PARTICIPANTS: A total of 210 patients with 1 or more visits for hypertension during the previous 3 years. MAIN OUTCOME MEASURES: Patient characteristics, current antihypertensive therapies, most recent blood pressure measurements, and compelling indications according to the 2006 Canadian Hypertension Education Program recommendations. RESULTS: A total of 185 subjects (88%) were prescribed antihypertensive medications, and 89 (42%) had controlled hypertension. Younger subjects, people with diabetes, and people not receiving antihypertensive medication therapy appeared less likely to have controlled hypertension. There were 76 subjects (36%) prescribed 1 antihypertensive medication, 65 subjects (31%) prescribed 2 antihypertensive medications, and 44 (21%) prescribed 3 or more antihypertensive medications. Angiotensin-converting enzyme inhibitors were prescribed for 51% of the subjects, diuretics for 47%, beta-blockers for 27%, calcium channel blockers for 23%, angiotensin receptor blockers for 20%, and alpha-blockers for 1%. CONCLUSION: Hypertension treatment and control rates in this academic family medicine clinic appear to be better than those in the general population. Following the principles of a continuous quality improvement process, this information will serve as an important foundation for identifying areas to improve hypertension management in the clinic.

Post-operative arterio-venous fistula blood flow influences primary and secondary patency following access surgery.

PURPOSE: Primary arteriovenous fistula arterio venous fistula (AVF) formation has proven to be the best and optimal vascular access for the majority of haemodialysis patients. At present there are limited data to suggest which haemodynamic parameters most correlate with the likelihood of early failure. The aim of this study is to identify the haemodynamic predictors of early failure, hence identify which fistulae may benefit from timely pre-emptive intervention. MATERIAL AND METHODS: Retrospective analysis of data was performed of 201 patients undergoing native AVF creation over a one year period. Demographic details, co-morbidity, preoperative vessel calibre were collected. Flow was measured by duplex ultrasound post operatively. RESULTS: Preoperative vein calibre (p = 0.01) and fistula flow (p < 0.001) positively affected primary patency. Age, gender, ethnicity, type of fistula, hypertension and preoperative arterial calibre did not influence outcome. Regression analysis showed that the strength of correlation between early postoperative fistula flow and patency decreased progressively with time. Six week flow predicts early, but not late, failure. ROC analysis identified 300 ml/min flow as the best predictor of patency. Fistulae with flow above 300 ml/min were more likely to remain patent over the next 12 months (p < 0.001, HR = 7.4). CONCLUSION: Postoperative fistula flow of less than 300 ml/min identifies AVFs at high risk of early failure. These may be candidates for early intervention with balloon assisted maturation. The findings of this retrospective cohort study strongly support the need for a more robust prospectively designed trial identifying haemodynamic factors that can predict mid and long-term AVF patency.

Identification of gene fusion transcripts by transcriptome sequencing in BRCA1-mutated breast cancers and cell lines.

BACKGROUND: Gene fusions arising from chromosomal translocations have been implicated in cancer. However, the role of gene fusions in BRCA1-related breast cancers is not well understood. Mutations in BRCA1 are associated with an increased risk for breast cancer (up to 80% lifetime risk) and ovarian cancer (up to 50%). We sought to identify putative gene fusions in the transcriptomes of these cancers using high-throughput RNA sequencing (RNA-Seq). METHODS: We used Illumina sequencing technology to sequence the transcriptomes of five BRCA1-mutated breast cancer cell lines, three BRCA1-mutated primary tumors, two secretory breast cancer primary tumors and one non-tumorigenic breast epithelial cell line. Using a bioinformatics approach, our initial attempt at discovering putative gene fusions relied on analyzing single-end reads and identifying reads that aligned across exons of two different genes. Subsequently, latter samples were sequenced with paired-end reads and at longer cycles (producing longer reads). We then refined our approach by identifying misaligned paired reads, which may flank a putative gene fusion junction. RESULTS: As a proof of concept, we were able to identify two previously characterized gene fusions in our samples using both single-end and paired-end approaches. In addition, we identified three novel in-frame fusions, but none were recurrent. Two of the candidates, WWC1-ADRBK2 in HCC3153 cell line and ADNP-C20orf132 in a primary tumor, were confirmed by Sanger sequencing and RT-PCR. RNA-Seq expression profiling of these two fusions showed a distinct overexpression of the 3' partner genes, suggesting that its expression may be under the control of the 5' partner gene's regulatory elements. CONCLUSIONS: In this study, we used both single-end and paired-end sequencing strategies to discover gene fusions in breast cancer transcriptomes with BRCA1 mutations. We found that the use of paired-end reads is an effective tool for transcriptome profiling of gene fusions. Our findings suggest that while gene fusions are present in some BRCA1-mutated breast cancers, they are infrequent and not recurrent. However, private fusions may still be valuable as potential patient-specific biomarkers for diagnosis and treatment.

Rethinking ovarian cancer: recommendations for improving outcomes.

There have been major advances in our understanding of the cellular and molecular biology of the human malignancies that are collectively referred to as ovarian cancer. At a recent Helene Harris Memorial Trust meeting, an international group of researchers considered actions that should be taken to improve the outcome for women with ovarian cancer. Nine major recommendations are outlined in this Opinion article.