No abstract

APOBEC enzymes are responsible for a mutation signature (TCW>T/G) implicated in a wide variety of tumors. We explore the APOBEC mutational signature in bladder cancer and the relationship with specific mutations, molecular subtype, gene expression, and survival using sequencing data from The Cancer Genome Atlas (n = 395), Beijing Genomics Institute (n = 99), and Cancer Cell Line Encyclopedia. Tumors were split into “APOBEC-high” and “APOBEC-low” based on APOBEC enrichment. Patients with APOBEC-high tumors have better overall survival compared to those with APOBEC-low tumors (38.2 vs. 18.5 months, p = 0.005). APOBEC-high tumors are more likely to have mutations in DNA damage response genes (TP53, ATR, BRCA2) and chromatin regulatory genes (ARID1A, MLL, MLL3), while APOBEC-low tumors are more likely to have mutations in FGFR3 and KRAS. APOBEC3A and APOBEC3B expression correlates with mutation burden, regardless of bladder tumor molecular subtype. APOBEC mutagenesis is associated with increased expression of immune signatures, including interferon signaling, and expression of APOBEC3B is increased after stimulation of APOBEC-high bladder cancer cell lines with IFNγ. In summary, APOBEC-high tumors are more likely to have mutations in DNA damage response and chromatin regulatory genes, potentially providing more substrate for APOBEC enzymes, leading to a hypermutational phenotype and the subsequent enhanced immune response.

The N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) mouse model is an attractive model system of muscle-invasive bladder cancer (MIBC) as it recapitulates the histology of human tumors in a background with intact immune system. However, it was unknown whether this carcinogen-induced model also mimicked human MIBC at the molecular and mutational level. In our study, we analyzed gene expression and mutational landscape of the BBN model by next-generation sequencing followed by a bioinformatic comparison to human MIBC using data from The Cancer Genome Atlas and other repositories. BBN tumors showed overexpression of markers of basal cancer subtype, and had a high mutation burden with frequent Trp53 (80%), Kmt2d (70%), and Kmt2c (90%) mutations by exome sequencing, similar to human MIBC. Many variants corresponded to human cancer hotspot mutations, supporting their role as driver mutations. We extracted two novel mutational signatures from the BBN mouse genomes. The integrated analysis of mutation frequencies and signatures highlighted the contribution of aberrations to chromatin regulators and genetic instability in the BBN tumors. Together, our study revealed several similarities between human MIBC and the BBN mouse model, providing a strong rationale for its use in molecular and drug discovery studies.

Survival of patients with urothelial carcinoma (including bladder cancer and upper tract urothelial carcinoma) is limited by our current approaches to staging, surgery, and chemotherapy. Large-scale, next-generation sequencing collaborations, such as The Cancer Genome Atlas, have already identified drivers and vulnerabilities of urothelial carcinoma. This disease has a high degree of mutational heterogeneity and a high frequency of somatic mutations compared with other solid tumours, potentially resulting in an increased neoantigen burden. Mutational heterogeneity is mediated by multiple factors including the apolipoprotein B mRNA editing enzyme catalytic polypeptide family of enzymes, smoking exposure, viral integrations, and intragene and intergene fusion proteins. The mutational landscape of urothelial carcinoma, including specific mutations in pathways and driver genes, such as FGFR3, ERBB2, PIK3CA, TP53, and STAG2, affects tumour aggressiveness and response to therapy. The next generation of therapies for urothelial carcinoma will be based on patient-specific targetable mutations found in individual tumours. This personalized-medicine approach to urothelial carcinoma has already resulted in unique clinical trial design and has the potential to improve patient outcomes and survival.

Transrectal ultrasound-guided prostate needle biopsy (PB) is considered the gold standard for the diagnosis of prostate cancer. Recently, lower urinary tract symptoms and erectile dysfunction have been reported following PB. We reviewed the literature on PB and these symptoms and summarized known findings between these conditions and other variables, such as periprostatic nerve block, saturation biopsy, serial biopsies, and psychological factors associated with PB and cancer. A PubMed search was performed using keywords "prostate biopsy," "complications," "erectile dysfunction," "lower urinary tract symptoms," "anxiety," and "quality of life." Eleven key papers are discussed and personal experience is drawn upon. Based upon available evidence, PB appears to be associated with short-term exacerbation of urinary symptoms in some men, as well as associated with anxiety and temporary erectile dysfunction, without a distinct relationship to periprostatic nerve block or the number of cores biopsied. Additional studies are warranted to determine the definitive etiology of these symptoms and to determine if interventions could reduce patient morbidity. In the interim, patients should be educated and counseled about these risks before undergoing PB.

1 Prostaglandins play a major role in maintaining ductal patency in utero. Ductal tone is regulated by both locally released and circulating vasodilatory prostaglandins. In infants with ductus arteriosus-dependent congenital heart disease, ductal patency is maintained by intravenous administration of prostaglandin (PG) E 1 . Little information is available regarding the expression of prostaglandin receptors in man.2 By means of RT ± PCR and immunohistochemistry we studied the expression of the PGI 2 receptor (IP), the four di erent PGE 2 receptors (EP1, EP2, EP3 and EP4), and the receptors for thromboxane (Tx) A 2 (TP), PGD 2 (DP) and PGF 2a (FP) in the ductus arteriosus of three newborn infants with ductus arteriosus-dependent congenital heart disease and intravenous infusion of PGE 1 and of one 8 month old child with a patent ductus arteriosus. 3 The EP3, EP4, FP, IP and TP receptor were markedly expressed at the mRNA and protein level, whereas the EP2 receptor was weakly expressed and the EP1 receptor was detected in two out of four tissue specimens only. The DP receptor was not detected in any of the samples. The most pronounced expression, which was located in the media of the ductus arteriosus, was observed for the EP4 and TP receptors followed by IP and FP receptor protein.4 These data indicate that ductal patency during the infusion of PGE 1 in infants with ductus arteriosus-dependent congenital heart disease might be mediated by the EP4 and IP receptor. The data further suggest that a heterogeneous population of prostanoid receptors may contribute to the regulation of ductus arteriosus tone in humans.

The verification of nuclear warheads for arms control involves a paradox: international inspectors will have to gain high confidence in the authenticity of submitted items while learning nothing about them. Proposed inspection systems featuring 'information barriers', designed to hide measurements stored in electronic systems, are at risk of tampering and snooping. Here we show the viability of a fundamentally new approach to nuclear warhead verification that incorporates a zero-knowledge protocol, which is designed in such a way that sensitive information is never measured and so does not need to be hidden. We interrogate submitted items with energetic neutrons, making, in effect, differential measurements of both neutron transmission and emission. Calculations for scenarios in which material is diverted from a test object show that a high degree of discrimination can be achieved while revealing zero information. Our ideas for a physical zero-knowledge system could have applications beyond the context of nuclear disarmament. The proposed technique suggests a way to perform comparisons or computations on personal or confidential data without measuring the data in the first place.

What's known on the subject? and What does the study add? There have been several studies that have suggested there may be a relationship between prostate biopsy and erectile function and LUTS. Previous studies have suggested a specific association between the type of local anaesthesia administered and/or the number of biopsies performed. Other studies have suggested an exacerbation of LUTS after prostate biopsy. The present study identifies a positive cancer diagnosis as a novel characteristic that may explain a relationship between biopsy and worsening erectile function. Objective To evaluate prospectively the characteristics, erectile function and lower urinary tract symptoms (LUTS) of men undergoing prostate needle biopsy (PNBx). Patients and Methods From 2008 to 2011, 134 men were prospectively administered the International Index of Erectile Function (IIEF), American Urological Association Symptom Index (AUA‐SI), and quality‐of‐life (QoL) questionnaires before and after undergoing a single 12‐core PNBx. Comparisons of IIEF and AUA‐SI scores before and after PNBx, based upon baseline characteristics and prostate cancer (PCa) diagnosis, were performed. Univariable and multivariable logistic regression models were used to characterize predictors of change in IIEF scores. Results In the 85 men who fulfilled the inclusion criteria, there were no significant differences between the mean (sd) total pre‐biopsy and the mean (sd) post‐biopsy IIEF scores: 57.8 (12.9) vs 54.3 (17.2). Subgroup analysis showed that men who had biopsy‐proven PCa had significantly greater changes in their post‐biopsy IIEF scores compared with men without (−10.1 vs. 1.0; P < 0.001). After specific analyses of the IIEF domains in these groups we found significant decreases in every domain, including erectile function (P = 0.01). On multivariate analyses, only PCa diagnosis was associated with a significant change in IIEF (odds ratio 7.2; P = 0.003). There were no differences in AUA‐SI or QoL scores in the overall population or in subgroups. Conclusions Cancer diagnosis appears to have an adverse effect on the erectile function of men undergoing PNBx but no effect on LUTS. This study highlights a potential negative psychological confounder that may influence erectile function before the treatment of PCa. Additional prospective trials evaluating these relationships are warranted.