We evaluated the activity of regorafenib, an oral multikinase inhibitor, in advanced gastric adenocarcinoma.
We conducted an international (Australia and New Zealand, South Korea, and Canada) ...randomized phase II trial in which patients were randomly assigned at a two-to-one ratio and stratified by lines of prior chemotherapy for advanced disease (one v two) and region. Eligible patients received best supportive care plus regorafenib 160 mg or matching placebo orally on days 1 to 21 of each 28-day cycle until disease progression or prohibitive adverse events occurred. The primary end point was progression-free survival (PFS). Final analysis included data to December 31, 2014.
A total of 152 patients were randomly assigned from November 7, 2012, to February 25, 2014, yielding 147 evaluable patients (regorafenib, n = 97; placebo, n = 50). Baseline characteristics were balanced. Median PFS significantly differed between groups (regorafenib, 2.6 months; 95% CI, 1.8 to 3.1 and placebo, 0.9 months; 95% CI, 0.9 to 0.9; hazard ratio HR, 0.40; 95% CI, 0.28 to 0.59; P < .001). The effect was greater in South Korea than in Australia, New Zealand, and Canada combined (HR, 0.12 v 0.61; interaction P < .001) but consistent across age, neutrophil-to-lymphocyte ratio, primary site, lines of chemotherapy, peritoneal metastasis presence, number of metastatic sites, and plasma vascular endothelial growth factor A. A survival trend in favor of regorafenib was seen (median, 5.8 months; 95% CI, 4.4 to 6.8 v 4.5 months; 95% CI, 3.4 to 5.2; HR, 0.74; P = .147). Twenty-nine patients assigned to placebo received open-label regorafenib after disease progression. Regorafenib toxicity was similar to that previously reported.
In this phase II trial, regorafenib was effective in prolonging PFS in refractory advanced gastric adenocarcinoma. Regional differences were found, but regorafenib was effective in both regional groups. A phase III trial is planned.
PurposeThe Upper Gastrointestinal Cancer Registry (UGICR) was developed to monitor and improve the quality of care provided to patients with upper gastrointestinal cancers in Australia.ParticipantsIt ...supports four cancer modules: pancreatic, oesophagogastric, biliary and primary liver cancer. The pancreatic cancer (PC) module was the first module to be implemented, with others being established in a staged approach. Individuals are recruited to the registry if they are aged 18 years or older, have received care for their cancer at a participating public/private hospital or private clinic in Australia and do not opt out of participation.Findings to dateThe UGICR is governed by a multidisciplinary steering committee that provides clinical governance and oversees clinical working parties. The role of the working parties is to develop quality indicators based on best practice for each registry module, develop the minimum datasets and provide guidance in analysing and reporting of results. Data are captured from existing data sources (population-based cancer incidence registries, pathology databases and hospital-coded data) and manually from clinical records. Data collectors directly enter information into a secure web-based Research Electronic Data Capture (REDCap) data collection platform. The PC module began with a pilot phase, and subsequently, we used a formal modified Delphi consensus process to establish a core set of quality indicators for PC. The second module developed was the oesophagogastric cancer (OGC) module. Results of the 1 year pilot phases for PC and OGC modules are included in this cohort profile.Future plansThe UGICR will provide regular reports of risk-adjusted, benchmarked performance on a range of quality indicators that will highlight variations in care and clinical outcomes at a health service level. The registry has also been developed with the view to collect patient-reported outcomes (PROs), which will further add to our understanding of the care of patients with these cancers.
Adenomatous polyposis of the colon is often secondary to an inherited mutation in adenomatous polyposis coli (APC) gene, however, approximately one third of patients have no family history of the ...disease. We studied the phenotype and genotype of adenomatous polyposis in patients without a family history.
A cohort of 57 unrelated adenomatous polyposis patients were evaluated. Seventeen patients with no family history were compared with 40 patients who had a positive family history of the disease. Family history and medical records were collected and analyzed. Germline APC and Mut Y homologue (MYH) testing was undertaken.
Patients without a family history were diagnosed with polyposis at an older age (41 years vs. 32 years) and presenting more frequently with symptoms (76 vs 20, P < 0.05). The number of colonic polyps and frequency of extracolonic manifestation associated with adenomatous polyposis did not differ between the two groups. APC mutations were detected less frequently among patients without a family history of the disease (4 out of 17 vs 25 out of 40, P=0.007), even among those with greater than 100 colorectal adenomas (4 out of 12 versus 21 out of 29, P=0.03). One homozygous MYH mutation carrier (G382D) was detected among the six patients without a family history and without a germline APC mutation who were tested.
Adenomatous polyposis patients without a family history are usually diagnosed with symptoms, and at a later age. Phenotypically, they are similar to those with a family history. However, germline APC mutations are detected far less frequently in patients without a family history. A small percentage of these cases may be secondary to biallelic germline MYH mutations.
Colorectal cancer in the commonest internal malignancy in western society today. At least a third of the incidence is likely to be due entirely or in part to inherited genetic factors. Over the last ...15 years several genes have been described in which germline mutation leading to increased colorectal cancer risk may occur. The commonest are Hereditary Non-Polyposis Colorectal Cancer (HNPCC), which accounts for around 1-4% of colorectal cancer diagnosis without polyposis and is caused by mutations in mismatch repair genes and Familial Adenomatous Polyposis caused by mutations in the AFC gene. In this thesis two related themes are addressed. Firstly I examine clinical, pathologic and molecular genetic information in kindreds recruited from family cancer clinics in order to investigate several relevant clinical problems relating to decisions regarding genetic testing and clustering of non-HNPCC families. Secondly, the group of individuals and families with multiple colorectal polyps without known genetic cause are investigated in several ways. A candidate gene analysis is undertaken looking for germline changes, an analysis of adenomas from such individuals for informative somatic changes is performed and I describe a new inherited syndrome of colorectal cancer and polyposis, MYH associated polyposis as well as the pathway of tumourigenesis in affected individuals.
Activation of the canonical TGF-β signaling pathway provides growth inhibitory signals in the normal intestinal epithelium. Colorectal cancers (CRCs) frequently harbor somatic mutations in the ...pathway members TGFBR2 and SMAD4, but to what extent mutations in SMAD2 or SMAD3 contribute to tumorigenesis is unclear. A cohort of 744 primary CRCs and 36 CRC cell lines were sequenced for SMAD4, SMAD2, and SMAD3 and analyzed for allelic loss by single-nucleotide polymorphism (SNP) microarray analysis. Mutation spectra were compared between the genes, the pathogenicity of mutations was assessed, and relationships with clinicopathologic features were examined. The prevalence of SMAD4, SMAD2, and SMAD3 mutations in sporadic CRCs was 8.6% (64 of 744), 3.4% (25 of 744), and 4.3% (32 of 744), respectively. A significant overrepresentation of two genetic hits was detected for SMAD4 and SMAD3, consistent with these genes acting as tumor suppressors. SMAD4 mutations were associated with mucinous histology. The mutation spectra of SMAD2 and SMAD3 were highly similar to that of SMAD4, both in mutation type and location within the encoded proteins. In silico analyses suggested the majority of the mutations were pathogenic, with most missense changes predicted to reduce protein stability or hinder SMAD complex formation. The latter altered interface residues or disrupted the phosphorylation-regulated Ser-Ser-X-Ser motifs within SMAD2 and SMAD3. Functional analyses of selected mutations showed reductions in SMAD3 transcriptional activity and SMAD2-SMAD4 complex formation. Joint biallelic hits in SMAD2 and SMAD3 were overrepresented and mutually exclusive to SMAD4 mutation, underlining the critical roles of these three proteins within the TGF-β signaling pathway.
Objective
To obtain insights into mechanisms mediating changes in cortical excitability induced by cathodal transcranial direct current stimulation (tDCS).
Methods
Neocortical slices were exposed to ...direct current stimulation (DCS) delivered through Ag/AgCl electrodes over a range of current orientations, magnitudes, and durations. DCS‐induced cortical plasticity and its receptor dependency were measured as the change in layer II/III field excitatory postsynaptic potentials by a multielectrode array, both with and without neurotransmitter receptor blockers or allosteric modulators. In vivo, tDCS was delivered to intact mice scalp via surface electrodes. Molecular consequences of DCS in vitro or tDCS in vivo were tested by immunoblot of protein extracted from stimulated slices or the neocortex harvested from stimulated intact mice.
Results
Cathodal DCS in vitro induces a long‐term depression (DCS‐LTD) of excitatory synaptic strength in both human and mouse neocortical slices. DCS‐LTD is abolished with an mGluR5 negative allosteric modulator, mechanistic target of rapamycin (mTOR) inhibitor, and inhibitor of protein synthesis. However, DCS‐LTD persists despite either γ‐aminobutyric acid type A receptor or N‐methyl‐D‐aspartate receptor inhibition. An mGluR5‐positive allosteric modulator, in contrast, transformed transient synaptic depression resultant from brief DCS application into durable DCS‐LTD.
Interpretation
We identify a novel molecular pathway by which tDCS modulates cortical excitability, and indicate a capacity for synergistic interaction between tDCS and pharmacologic mGluR5 facilitation. The findings support exploration of cathodal tDCS as a treatment of neurologic conditions characterized by aberrant regional cortical excitability referable to mGluR5‐mTOR signaling. Ann Neurol 2016;80:233–246
Lynch syndrome is a highly penetrant cancer predisposition syndrome caused by germline mutations in DNA mismatch repair (MMR) genes. We estimated the risks of primary cancers other than colorectal ...cancer following a diagnosis of colorectal cancer in mutation carriers.
We obtained data from the Colon Cancer Family Registry for 764 carriers of an MMR gene mutation (316 MLH1, 357 MSH2, 49 MSH6, and 42 PMS2), who had a previous diagnosis of colorectal cancer. The Kaplan-Meier method was used to estimate their cumulative risk of cancers 10 and 20 years after colorectal cancer. We estimated the age-, sex-, country- and calendar period-specific standardized incidence ratios (SIRs) of cancers following colorectal cancer, compared with the general population.
Following colorectal cancer, carriers of MMR gene mutations had the following 10-year risk of cancers in other organs: kidney, renal pelvis, ureter, and bladder (2%, 95% confidence interval CI = 1% to 3%); small intestine, stomach, and hepatobiliary tract (1%, 95% CI = 0.2% to 2%); prostate (3%, 95% CI = 1% to 5%); endometrium (12%, 95% CI = 8% to 17%); breast (2%, 95% CI = 1% to 4%); and ovary (1%, 95% CI = 0% to 2%). They were at elevated risk compared with the general population: cancers of the kidney, renal pelvis, and ureter (SIR = 12.54, 95% CI = 7.97 to 17.94), urinary bladder (SIR = 7.22, 95% CI = 4.08 to 10.99), small intestine (SIR = 72.68, 95% CI = 39.95 to 111.29), stomach (SIR = 5.65, 95% CI = 2.32 to 9.69), and hepatobiliary tract (SIR = 5.94, 95% CI = 1.81 to 10.94) for both sexes; cancer of the prostate (SIR = 2.05, 95% CI = 1.23 to 3.01), endometrium (SIR = 40.23, 95% CI = 27.91 to 56.06), breast (SIR = 1.76, 95% CI = 1.07 to 2.59), and ovary (SIR = 4.19, 95% CI = 1.28 to 7.97).
Carriers of MMR gene mutations who have already had a colorectal cancer are at increased risk of a greater range of cancers than the recognized spectrum of Lynch syndrome cancers, including breast and prostate cancers.
PIK3CA and PTEN mutations are prevalent in colorectal cancer and potential markers of response to mitogen-activated protein/extracellular signal-regulated kinase inhibitors and anti-EGF receptor ...antibody therapy. Relationships between phosphoinositide 3-kinase (PI3K) pathway mutation, clinicopathologic characteristics, molecular features, and prognosis remain controversial.
A total of 1,093 stage I-IV colorectal cancers were screened for PIK3CA (exons 9 and 20), KRAS (codons 12-13), BRAF (codon 600) mutations, and microsatellite instability (MSI). PTEN (exons 3-8) and CpG island methylator phenotype (CIMP) status were determined in 744 and 489 cases. PIK3CA data were integrated with 17 previous reports (n = 5,594).
PIK3CA and PTEN mutations were identified in 11.9% and 5.8% of colorectal cancers. PTEN mutation was associated with proximal tumors, mucinous histology, MSI-high (MSI-H), CIMP-high (CIMP-H), and BRAF mutation (P < 0.02). PIK3CA mutation was related to older age, proximal tumors, mucinous histology, and KRAS mutation (P < 0.04). In integrated cohort analysis, PIK3CA exon 9 and 20 mutations were overrepresented in proximal, CIMP-low (CIMP-L), and KRAS-mutated cancers (P ≤ 0.011). Comparing PIK3CA exonic mutants, exon 20 mutation was associated with MSI-H, CIMP-H, and BRAF mutation, and exon 9 mutation was associated with KRAS mutation (P ≤ 0.027). Disease-free survival for stage II/III colorectal cancers did not differ by PI3K pathway status.
PI3K pathway mutation is prominent in proximal colon cancers, with PIK3CA exon 20 and PTEN mutations associated with features of the sessile-serrated pathway (MSI-H/CIMP-H/BRAF(mut)), and PIK3CA exon 9 (and to a lesser extent exon 20) mutation associated with features of the traditional serrated pathway (CIMP-L/KRAS(mut)) of tumorigenesis. Our data highlight the PI3K pathway as a therapeutic target in distinct colorectal cancer subtypes.
BackgroundSurgical management of colon cancer for patients with Lynch syndrome who carry a mismatch repair (MMR) gene mutation is controversial. The decision to remove more or less of the colon ...involves the consideration of a relatively high risk of metachronous colorectal cancer (CRC) with the impact of more extensive surgery.ObjectiveTo estimate and compare the risks of metachronous CRC for patients with Lynch syndrome undergoing either segmental or extensive (subtotal or total) resection for first colon cancer.DesignRisk of metachronous CRC was estimated for 382 MMR gene mutation carriers (172 MLH1, 167 MSH2, 23 MSH6 and 20 PMS2) from the Colon Cancer Family Registry, who had surgery for their first colon cancer, using retrospective cohort analysis. Age-dependent cumulative risks of metachronous CRC were calculated using the Kaplan–Meier method. Risk factors for metachronous CRC were assessed by a Cox proportional hazards regression.ResultsNone of 50 subjects who had extensive colectomy was diagnosed with metachronous CRC (incidence rate 0.0; 95% CI 0.0 to 7.2 per 1000 person-years). Of 332 subjects who had segmental resections, 74 (22%) were diagnosed with metachronous CRC (incidence rate 23.6; 95% CI 18.8 to 29.7 per 1000 person-years). For those who had segmental resections, incidence was statistically higher than for those who had extensive surgery (P <0.001). Cumulative risk of metachronous CRC was 16% (95% CI 10% to 25%) at 10 years, 41% (95% CI 30% to 52%) at 20 years and 62% (95% CI 50% to 77%) at 30 years after segmental colectomy. Risk of metachronous CRC reduced by 31% (95% CI 12% to 46%; p=0.002) for every 10 cm of bowel removed.ConclusionsPatients with Lynch syndrome with first colon cancer treated with more extensive colonic resection have a lower risk of metachronous CRC than those receiving less extensive surgery. This finding will better inform decision-making about the extent of primary surgical resection.
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