Germline mutations in the BRCA1 or BRCA2 (BRCA) genes predispose to hereditary breast and ovarian cancer and, mostly in the case of BRCA2, are also prevalent in cases of pancreatic and prostate ...malignancies. Tumours from these patients tend to lose both copies of the wild-type BRCA gene, which makes them exquisitely sensitive to platinum drugs and poly(ADP-ribose) polymerase inhibitors (PARPi), treatments of choice in these disease settings. Reversion secondary mutations with the capacity of restoring BRCA protein expression have been documented in the literature as bona fide mechanisms of resistance to these treatments.
We analysed published sequencing data of BRCA genes (from tumour or circulating tumour DNA) in 327 patients with tumours harbouring mutations in BRCA1 or BRCA2 (234 patients with ovarian cancer, 27 with breast cancer, 13 with pancreatic cancer, 11 with prostate cancer and 42 with a cancer of unknown origin) that progressed on platinum or PARPi treatment.
We describe 269 cases of reversion mutations in 86 patients in this cohort (26.0%). Detailed analyses of the reversion events highlight that most amino acid sequences encoded by exon 11 in BRCA1 and BRCA2 are dispensable to generate resistance to platinum or PARPi, whereas other regions are more refractory to sizeable amino acid losses. They also underline the key role of mutagenic end-joining DNA repair pathways in generating reversions, especially in those affecting BRCA2, as indicated by the significant accumulation of DNA sequence microhomologies surrounding deletions leading to reversion events.
Our analyses suggest that pharmacological inhibition of DNA end-joining repair pathways could improve durability of drug treatments by preventing the acquisition of reversion mutations in BRCA genes. They also highlight potential new therapeutic opportunities when reversions result in expression of hypomorphic versions of BRCA proteins, especially with agents targeting the response to DNA replication stress.
•Comprehensive analysis of reversion mutations in BRCA genes identified in clinical cases of resistance to platinum or PARPi.•Revertant proteins are devoid of parts of the original sequence, identifying key protein functions involved in resistance.•Hypomorph revertant BRCA proteins suggest potential new therapeutic opportunities to overcome resistance.•Prevalence of mutational end-joining DNA repair mechanisms leading to reversions, especially in those affecting BRCA2.•Pharmacological inhibition of mutational end-joining DNA repair could improve durability of drug treatments.
Modulating the DNA damage response and repair (DDR) pathways is a promising strategy for boosting cancer immunotherapy. Ceralasertib (AZD6738) is an oral inhibitor of the serine/threonine protein ...kinase ataxia telangiectasia and Rad3-related protein, which is crucial for DDR.
This phase II trial evaluated ceralasertib plus durvalumab for the treatment of patients with metastatic melanoma who had failed anti-programmed cell death protein 1 therapy.
Among the 30 patients, we observed an overall response rate of 31.0% and a disease control rate of 63.3%. Responses were evident across patients with acral, mucosal, and cutaneous melanoma. The median duration of response was 8.8 months (range, 3.8-11.7 months). The median progression-free survival was 7.1 months (95% confidence interval, 3.6-10.6 months), and the median overall survival was 14.2 months (95% confidence interval, 9.3-19.1 months). Common adverse events were largely hematologic and manageable with dose interruptions and reductions. Exploratory biomarker analysis suggested that tumors with an immune-enriched microenvironment or alterations in the DDR pathway were more likely to respond to the study treatment.
We conclude that ceralasertib in combination with durvalumab has promising antitumor activity among patients with metastatic melanoma who have failed anti-programmed cell death protein 1 therapy, and constitute a population with unmet needs.
•Combination of ceralasertib and durvalumab had a tolerable safety profile in patients with metastatic melanoma.•Combination treatment resulted in median progression-free survival of 7.1 months and median overall survival of 14.2 months.•Our data suggest that this combination could be used to salvage patients with immunotherapy-resistant melanoma.•Ceralasertib plus durvalumab is worthy of further investigation for melanoma after failure of frontline immunotherapy.
Maintenance of the highly plastic intestinal epithelium relies upon stem cells localized to intestinal crypts. Recent evidence suggests muscarinic acetylcholine signaling impacts epithelial barrier ...function, proliferation, and apoptosis. We hypothesized that the intestinal crypt base would express specific muscarinic acetylcholine receptors that drive proliferation in this critical region. Intestinal segments spanning the small bowel were procured from wild-type C57Bl/6 mice to determine muscarinic acetylcholine receptor mRNA expression and create sections on laser capture microdissection slides for analysis of crypt base cells. RT-PCR was performed using primers targeting the five muscarinic acetylcholine receptor subtypes (M1–M5), LGR5, BIII-tubulin, and GAPDH. To determine the effects of muscarinic agonism in vivo, osmotic pumps delivering the M1 muscarinic acetylcholine receptor agonist McN-A-343 were implanted into wild type mice for one week. Segments were harvested, histologic sections created, and morphometric and proliferative parameters measured. In full-thickness intestinal samples, muscarinic acetylcholine receptor subtypes M1–M4 were found in all regions, while M5 was localized to the proximal jejunum. In crypt-base cells, the M1 muscarinic acetylcholine receptor subtype was the only subtype found and was present in all regions. LGR5 was present in all laser capture microdissection samples, indicating the capture of intestinal stem cells. In vivo experiments conducted with McN-A-343 revealed significantly increased villus height, crypt depth, and crypt-cell proliferation. The presence of M1 muscarinic acetylcholine receptor mRNA within the stem cell niche in the intestinal crypt base coupled with increased mucosal growth with M1 receptor stimulation in vivo suggests that the cholinergic system, via the M1 muscarinic acetylcholine receptor, is a critical mediator of intestinal mucosal homeostasis.
Impact statement
Localization of a specific subtype of the muscarinic acetylcholine receptor in the crypt stem cell compartment suggests a critical role in intestinal mucosal homeostasis. Here we demonstrate the localization of the M1 muscarinic acetylcholine receptor to the stem cell compartment and demonstrate increase morphometric and proliferative parameters when this is stimulated in vivo. These data provide novel information about this complex signaling microenvironment and offer potential future therapeutic targets for future study.
In breast cancer (BC) patients, local recurrences often arise in proximity of the surgical scar, suggesting that response to surgery may have a causative role. Radiotherapy (RT) after lumpectomy ...significantly reduces the risk of recurrence. We investigated the direct effects of surgery and of RT delivered intraoperatively (IORT), by collecting irradiated and non-irradiated breast tissues from BC patients, after tumor removal. These breast tissue specimens have been profiled for their microRNA (miR) expression, in search of differentially expressed miR among patients treated or not with IORT. Our results demonstrate that IORT elicits effects that go beyond the direct killing of residual tumor cells. IORT altered the wound response, inducing the expression of miR-223 in the peri-tumoral breast tissue. miR-223 downregulated the local expression of epidermal growth factor (EGF), leading to decreased activation of EGF receptor (EGFR) on target cells and, eventually, dampening a positive EGF-EGFR autocrine/paracrine stimulation loop induced by the post-surgical wound-healing response. Accordingly, both RT-induced miR-223 and peri-operative inhibition of EGFR efficiently prevented BC cell growth and reduced recurrence formation in mouse models of BC. Our study uncovers unknown effects of RT delivered on a wounded tissue and prompts to the use of anti-EGFR treatments, in a peri-operative treatment schedule, aimed to timely treat BC patients and restrain recurrence formation.
Abstract
Background
The burden of frail patients undergoing emergency general surgery (EGS) is increasing rapidly and this population is particularly susceptible to postoperative cardiopulmonary ...complications and mortality. We aimed to determine the association between frailty, as defined by the previously described modified frailty index (mFI), and postoperative respiratory complications (unplanned reintubation, pneumonia, and prolonged ventilation), cardiac complications (myocardial infarction and cardiac arrest), and mortality. We also sought to identify the most significant determinants of frailty in the highest risk patients based on the specific variables comprising the mFI.
Methods
We performed a retrospective observational analysis of the prospectively collected American College of Surgeons National Surgical Quality Improvement Program database. Files from 2005 to 2015 identified 132,765 inpatients who underwent EGS. mFI scores were calculated for each patient. The effect of increasing frailty on unplanned reintubation, pneumonia, prolonged ventilation, myocardial infarction, cardiac arrest, and mortality was evaluated using bivariate analysis. Multivariable logistic regression was used to compare mFI with additional predictor variables including race, gender, physical status as defined by the American Society of Anesthesiologists, disseminated cancer, renal failure, smoking status, sepsis, wound presence/classification, dyspnea, and previous ventilator dependence.
Results
Unplanned reintubation, pneumonia, prolonged ventilation, myocardial infarction, cardiac arrest, and mortality were significantly associated with frailty, and the odds of each postoperative complication increased with increasing mFI score. Of the frailest patients (mFI ≥3) that experienced cardiopulmonary complications or mortality, the variables of the mFI that contributed most to frailty were hypertension requiring medication and functional status before surgery.
Conclusions
A higher mFI score is associated with increased odds of postoperative cardiopulmonary complications and mortality in the EGS population. Specific variables of the mFI can also provide valuable information for assessing odds in the frailest patients undergoing EGS.
Socioeconomic factors such as race, insurance, and income quartiles have been identified as independent risk factors in emergency general surgery (EGS), but this impact has not been studied over ...time. We sought to identify trends in disparities in EGS-related operative mortality over a 20-y period.
The National Inpatient Sample was used to identify patient encounters coded for EGS in 1993, 2003, and 2013. Logistic regression models were used to examine the adjusted relationship between race, primary payer status, and median income quartiles and in-hospital mortality after adjusting for patients' age, gender, Elixhauser comorbidity score, and hospital region, size, and location-cum-teaching status.
We identified 391,040 patient encounters. In 1993, Black race was associated with higher odds of in-hospital mortality (odds ratio 95% confidence interval: 1.35 1.20-1.53) than White race, although this difference dissipated in subsequent years. Medicare, Medicaid, and underinsured patients had a higher odds of mortality than those with private insurance for the entire 20-y period; only the disparity in the underinsured decreased over time (1993, 1.63 1.35-1.98; 2013, 1.41 1.20-1.67). In 2003 (1.23 1.10-1.38) and 2013 (1.23 1.11-1.37), patients from the lowest income quartile were more likely to die after EGS than patients from the highest income quartile.
Socioeconomic disparities in EGS-related operative morality followed inconsistent trends. Over time, while gaps in in-hospital mortality among Blacks and Whites have narrowed, disparities among patients belonging to lowest income quartile have worsened. Medicare and Medicaid beneficiaries continued to experience higher odds of in-hospital mortality relative to those with private insurance.
Background
Enteric serotonin may function as a mucosal growth factor. Previous work demonstrated increased crypt cell proliferation and intestinal mucosal surface area with potentiation of serotonin. ...While an indirect mechanism was postulated to explain these effects, the presence of 5-HT4 receptors on enterocytes raises the possibility of a direct action of serotonin. We hypothesized that a 5-HT4 specific agonist, prucalopride, would stimulate intestinal mucosal growth and enhance absorptive function in the murine small intestine.
Methods
Adult wild-type mice were treated parenterally with prucalopride for 14 days via surgically implanted osmotic pumps. In vivo
d
-xylose absorption was assessed by oral gavage and serum
d
-xylose measurements. On day 14, glucose absorption was assessed by instilling a glucose solution into isolated segments of small intestine. The bowel was harvested and examined for morphologic parameters and crypt cell proliferation.
Results
Villus height, crypt depth, and crypt proliferation were significantly increased in the distal small bowel of prucalopride-treated mice compared with control animals. Crypt depth was also increased in the proximal and middle small intestine in treated mice. There was no difference in
d
-xylose absorption throughout the study period; however, glucose absorption was significantly increased in the distal small intestine of prucalopride-treated mice.
Conclusion
Parenteral administration of the 5-HT4 receptor specific agonist, prucalopride, results in morphologic and functional changes in the murine small intestine that are most prominent in the distal small bowel. While further studies are necessary to delineate the mechanism, it is plausible that the effects are mediated by 5-HT4 receptors on enterocytes.
The Ladd procedure is the treatment of choice for patients with intestinal malrotation; however, the long-term outcomes of the laparoscopic Ladd procedure are not well documented. This study aimed to ...review the presentation, management, and outcomes of adult patients who underwent a laparoscopic Ladd procedure.
A retrospective review was conducted to identify adult patients with malrotation who underwent a laparoscopic Ladd procedure between January 1995 and June 2022 at the Mayo Clinic in Rochester, Minnesota. Patient details and follow-up data were obtained from the electronic medical records. Patients were invited to participate in a structured phone interview to assess symptoms and quality of life (QoL).
A total of 44 patients underwent the laparoscopic Ladd procedure. Of the 44 patients, 42 (95.5 %) were symptomatic, with 7 (16.7 %) presenting with acute symptoms. Moreover, 8 laparoscopic procedures (13.6 %) required conversion to an open procedure. The median estimated blood loss was 20 mL (IQR, 10–50), operative time was 2.3 h (IQR, 1.8–2.8), and hospital length of stay was 2 days (IQR, 2–3). Postoperative ileus was the most common complication (18.0 %). The median follow-up was 8.00 years (IQR, 2.25–13.00), with more than 90.0 % of patients having partial or complete symptom resolution. Of note, 28 patients (63.6 %) completed phone interviews. Moreover, 1 patient (2.0 %) reported a postoperative volvulus. When asked to compare their current symptoms with those preoperatively, 78.6 % of patients noted that they were significantly better. Furthermore, 85.7 % of patients reported that their QoL was significantly better after surgery. Finally, 96.4 % of patients would recommend the procedure to a friend or family member with the same condition.
The laparoscopic Ladd procedure is a safe and effective surgical procedure for adult patients with intestinal malrotation.
Biliary atresia (BA) causes progressive fibrosis and obliteration of the biliary tree, resulting in bile stasis and eventual liver dysfunction. It affects 1 in 10,000–18,000 infants, and if left ...untreated, universally leads to liver failure. The Kasai hepatoportoenterostomy (KPE) was developed as an effective surgical therapy for BA and can restore bile drainage into the intestine. Traditionally, the KPE procedure extra-corporealizes the liver to expose the portal plate. Here, we describe modifications to the procedure via a smaller incision in which the liver remains within the abdominal cavity and we compare the outcomes of this technique to previous institutional outcomes and to contemporary international series.
We identified all patients who underwent KPE for BA at a single institution between 1994 and 2012. Patient outcomes after the modified KPE performed from 2004 to 2012 were compared to data from infants who underwent the traditional KPE from 1994 to 2003.
Ninety-nine patients were identified. Fifty-two were in the traditional KPE group and 47 in the modified KPE group. There was no difference in mean age at surgery. Median follow-up was 64 months (traditional KPE) and 46 months (modified KPE). The rate of native liver survival (39.1% vs 48.5%), overall survival (89.2% vs 97.8%), liver transplant occurring under one year of age (36.5% vs 40.4%) and median time to liver transplant (188 vs 172 days) were not statistically different between groups (p > 0.05 for all comparisons). The results of the modified KPE compared favorably to published outcomes.
The described modifications to the KPE appear to yield equivalent outcomes when compared to the traditional KPE procedure and compare well with published outcomes in the literature. It is possible that the procedure described here results in less scarring and technically easier liver transplant procedures.
Level III.
Previous studies reveal a correlation between surgical volume and outcomes; thus, a similar relationship likely exists between trainee operative volume and technical competence. While routine ...hepatobiliary surgery is commonplace, trainee exposure to the more advanced procedures may be lacking. We hypothesize that experience in complex hepatobiliary procedures may be deficient both during general surgery residency and pediatric surgery fellowship training.
Case log data from the ACGME were queried for general surgery residents (2000-2017) and pediatric surgery fellows (2004-2017). Laparoscopic cholecystectomy was considered a routine hepatobiliary procedure for both specialties. For general surgery, hepatic lobectomy/segmentectomy and choledochoenteric anastomosis were considered complex and for pediatric surgery, hepatic lobectomy, biliary atresia and choledochal cyst procedures were considered complex.
Publicly available case log data from the ACGME.
General surgery residents and pediatric surgery fellows at ACGME-accredited training programs.
The number of trainees increased over the study period for both groups. Mean case volumes for laparoscopic cholecystectomy increased by 36% in surgery graduates and by 114% in pediatric surgery graduates. In surgery, the mean volumes for choledochoenteric anastomosis procedures decreased by 53% from 3.0 to 1.4 procedures/year with increasing variability in trainee experience. Volumes for hepatic lobectomy/segmentectomy increased by 68% from 3.4 to 5.7 procedures/year with decreasing variability. In pediatric surgery, case volumes for complex procedures were low (mean <4/year), highly variable among trainees, and appear unchanged between 2004 and 2017. In every year analyzed, at least 1 pediatric surgery trainee reported doing 0 cases in one of these complex categories.
Case logs suggest that the volume of complex hepatobiliary surgery remains low and highly variable in both disciplines with some trainees obtaining minimal or no exposure to certain cases. The relationship between these trends and the development of competency is worthy of further study.
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