Only patients with wild-type (WT) KRAS tumors benefit from anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (Mabs) in metastatic colorectal cancer (mCRC). Pyrosequencing is now ...widely used for the determination of KRAS mutation burden and a conservative cut-off point of 10% has been defined. Up until now, the impact of low-frequency KRAS mutations (<10%) on the response to anti-EGFR Mabs has yet to be evaluated.
Tumors from patients receiving anti-EGFR Mabs based on a WT genotype for KRAS, as determined using direct sequencing, have been retrospectively analyzed by pyrosequencing. Patients were categorized as WT (no KRAS mutation) or low-frequency mutation when KRAS mutation was <10% (KRAS low MT).
A total of 168 patients treated by anti-EGFR Mabs for mCRC were analyzed. According to pyrosequencing, 138 tumors remained KRAS WT, while 30 tumors were KRAS low MT. In the KRAS low MT and KRAS WT groups, the response rates were 6.7% and 37.0%, respectively, while stabilization amounted to 23.3% versus 32.6% and progression to 70% versus 29% (P < 0.01). Progression-free survival (PFS) was 2.7±0.5 months for KRAS low MT and was 6.0±0.3 months for KRAS WT (P < 0.01).
These results appear to validate consideration of low-frequency KRAS mutation tumors as positive, and justify a large-scale prospective study.
RAS mutations are currently sought for in tumor samples, which takes a median of almost 3weeks in western European countries. This creates problems in clinical situations that require urgent ...treatment and for inclusion in therapeutic trials that need RAS status for randomization. Analysis of circulating tumor DNA might help to shorten the time required to determine RAS mutational status before anti-epidermal growth factor receptor antibody therapy for metastatic colorectal cancer. Here we compared plasma with tissue RAS analysis in a large prospective multicenter cohort.
Plasma samples were collected prospectively from chemotherapy-naive patients and analyzed centrally by next-generation sequencing (NGS) with the colon lung cancer V2 Ampliseq panel and by methylation digital PCR (WIF1 and NPY genes). Tumoral RAS status was determined locally, in parallel, according to routine practice. For a minimal κ coefficient of 0.7, reflecting acceptable concordance (precision±0.07), with an estimated 5% of non-exploitable data, 425 subjects were necessary.
From July 2015 to December 2016, 425 patients were enrolled. For the 412 patients with available paired plasma and tumor samples, the κ coefficient was 0.71 95% confidence interval (CI), 0.64–0.77 and accuracy was 85.2% (95% CI, 81.4% to 88.5%). In the 329 patients with detectable ctDNA (at least one mutation or one methylated biomarker), the κ coefficient was 0.89 (95% CI, 0.84–0.94) and accuracy was 94.8% (95% CI, 91.9% to 97.0%). The absence of liver metastases was the main clinical factor associated with inconclusive circulating tumor DNA results odds ratio=0.11 (95% CI, 0.06–0.21). In patients with liver metastases, accuracy was 93.5% with NGS alone and 97% with NGS plus the methylated biomarkers.
This prospective trial demonstrates excellent concordance between RAS status in plasma and tumor tissue from patients with colorectal cancer and liver metastases, thus validating plasma testing for routine RAS mutation analysis in these patients.
Clinicaltrials.gov, NCT02502656.
Heme ligation in hemoglobin is typically assumed by the “proximal” histidine. Hydrophobic contacts, ionic interactions, and the ligation bond secure the heme between two α-helices denoted E and F. ...Across the hemoglobin superfamily, several proteins also use a “distal” histidine, making the native state a bis-histidine complex. The group 1 truncated hemoglobin from Synechocystis sp. PCC 6803, GlbN, is one such bis-histidine protein. Ferric GlbN, in which the distal histidine (His46 or E10) has been replaced with a leucine, though expected to bind a water molecule and yield a high-spin iron complex at neutral pH, has low-spin spectral properties. Here, we applied nuclear magnetic resonance and electronic absorption spectroscopic methods to GlbN modified with heme and amino acid replacements to identify the distal ligand in H46L GlbN. We found that His117, a residue located in the C-terminal portion of the protein and on the proximal side of the heme, is responsible for the formation of an alternative bis-histidine complex. Simultaneous coordination by His70 and His117 situates the heme in a binding site different from the canonical site. This new holoprotein form is achieved with only local conformational changes. Heme affinity in the alternative site is weaker than in the normal site, likely because of strained coordination and a reduced number of specific heme–protein interactions. The observation of an unconventional heme binding site has important implications for the interpretation of mutagenesis results and globin homology modeling.
Nitrate metabolism in Chlamydomonas reinhardtii involves THB1, a monomeric hemoglobin thought to function as a nitric oxide dioxygenase (NOD). NOD activity requires dioxygen and nitric oxide binding ...followed by a one-electron oxidation of the heme iron and nitrate release. Unlike pentacoordinate flavohemoglobins, which are efficient NODs, THB1 uses two iron axial ligands: the conserved proximal histidine and a distal lysine (Lys53). As a ligand in both the oxidized (ferric) and reduced (ferrous) states, Lys53 is expected to lower the reorganization energy associated with electron transfer and therefore facilitate reduction of the ferric enzyme. In ferrous THB1, however, Lys53 must be displaced for substrate binding. To characterize Lys53 dynamics, THB1 was studied at various pH, temperatures, and pressures by NMR spectroscopy. Structural information indicates that the protein fold and Lys53 environment are independent of the oxidation state. High-pressure NMR experiments provided evidence that displacement of Lys53 occurs through fast equilibrium (∼3–4 × 103 s–1 at 1 bar, 298 K) with a low-population intermediate in which Lys53 is neutral and decoordinated. Once decoordinated, Lys53 is able to orient toward solvent and become protonated. The global lysine decoordination/reorientation/protonation processes measured by 15N z -exchange spectroscopy are slow on the chemical shift time scale (101–102 s–1 at pH ≈ 6.5, 298 K) in both iron redox states. Thus, reorientation/protonation steps in ferrous THB1 appear to present a significant barrier for dioxygen binding, and consequently, NOD turnover. The results illustrate the role of distal ligand dynamics in regulating the kinetics of multistep heme redox reactions.
•The group Accept Voices appear to diminish the intensity of auditory hallucinations in participants.•Acceptance and mindfulness techniques seem to facilitate the acceptance of voices.•The Accept ...voices group decreases depression and anxiety symptoms post-therapy.•A short group therapy for voice management significantly improves coping with auditory hallucinations.
The objective of this study was to evaluate the potential impact of a third wave CBT group intervention for the management of auditory hallucinations in patients with schizophrenia.
38 patients with schizophrenia presenting with auditory hallucinations, followed in mental health services, participated in six sessions of a group based on acceptance and engagement therapy (ACT). The study followed a repeated single case experimental design (type A-B-A) based on the principle of a control phase followed by an intervention phase and a follow-up phase of similar duration. The various measurements were administered during the control phase, at pre-/post-group and six weeks after the last group session.
The results show a significant decrease in auditory hallucinations, as measured by the PSYRATS scale, during the treatment and follow-up phase, compared to the control phase. In addition, the participants saw significant reductions in depressive and anxious symptomatology (assessed with CDSS and SEAS), and increases in coping and acceptance in regards to voices (assessed using a study scale and VAAS). The level of Malevolence beliefs about voices (measured with BAVQ-R) also decreased significantly.
A brief group intervention based acceptance show promise in the reduction of the intensity of auditory hallucinations, depression and anxiety in patients with schizophrenia, while improving their acceptance.
Background
Lymphopenia is a predictor of the efficacy and hematological toxicity of chemotherapy in various advanced cancers. There is little data about this relationship in colorectal cancer. In ...this retrospective study, the influence of pretreatment lymphopenia on hematological toxicity and the efficacy of chemotherapy was investigated in colorectal cancer patients.
Patients and methods
In total, 260 patients were included in the study. Correlations between pre-treatment lymphopenia (lymphocyte count < 1,000/μl) and the occurrence of hematological toxicity and efficacy of first-line palliative chemotherapy were investigated.
Results
Lymphopenia was found in 49/260 (19%) patients. Ten of these patients with lymphopenia (20.4%) experienced severe hematological toxicity compared with 17 of the remaining 211 (8%) patients (
P
= 0.01). Lymphopenia was identified as an independent factor for hematological toxicity. Among patients who received palliative chemotherapy, the objective response rate was significantly lower in lymphopenic patients than in the other patients (12.5% vs. 40.2%;
P
= 0.004). Lymphopenia was strongly associated with shorter progression-free survival (median 4 vs. 7 months;
P
= 0.033) and shorter overall survival (median 16 vs. 24 months,
P
= 0.024). Multivariate analysis revealed that lymphopenia had an independent effect on survival.
Conclusions
Our findings show that lymphopenia is an independent predictive factor for both hematological toxicity and efficacy of chemotherapy in colorectal cancer. Pre-treatment lymphocyte count may represent a simple and new predictive biomarker of chemotherapy effects in colorectal cancer patients.
Small-bowel adenocarcinoma (SBA) is a rare tumor of poor prognosis. Data on the efficacy of chemotherapy for advanced SBA are scarce.
All patients with advanced SBA who received frontline ...chemotherapy from 1996 to 2008 were eligible for this retrospective multicenter study.
Ninety-three consecutive patients were included. In the entire population, the median progression-free survival (PFS) and overall survival (OS) times were 6.6 and 15.1 months, respectively. Median PFS times among patients treated with LV5FU2 (n = 10), FOLFOX (n = 48), FOLFIRI (n = 19) and LV5FU2-cisplatin (n = 16) were 7.7, 6.9, 6.0 and 4.8 months, respectively, while median OS times were 13.5, 17.8, 10.6 and 9.3 months, respectively. In multivariate analysis, World Health Organization performance status (PS) (P < 0.0001) and elevated serum levels of carcinoembryonic antigen (CEA) (P = 0.02) and carbohydrate antigen 19-9 (CA 19-9) (P = 0.03) were the only variables significantly associated with poor OS. In the subgroup of patients treated with platinum-based chemotherapy, multivariate analysis showed that LV5FU2-cisplatin was associated with poorer PFS (P < 0.0001) and OS (P = 0.02) compared with FOLFOX.
This is the largest study of chemotherapy in advanced SBA. Baseline PS and CEA and CA 19-9 levels were the main prognostic factors. FOLFOX seems to be the most effective platinum-based chemotherapy regimen.
Although malnutrition is known to be frequent in cancer patients, it has not been described in a selected population of patients with gastrointestinal malignancies under chemotherapy only. Physician ...judgment about malnutrition and risk factors for malnutrition were also evaluated. All consecutive in- and outpatients of 11 centers were prospectively enrolled in a cross-sectional 14-day period study and classified according to the French health recommendations Haute Autorité de Santé (HAS). Among 313 patients enrolled in 11 centers (mean age = 63 yr; range = 21-93; 67% male) mainly with colorectal (58%), pancreatic (15%), gastric (11%), and hepatobiliary (10%) primary tumors, the prevalence of malnutrition was 52%. Moderate and severe malnutrition was present in 27% and 25% of cases, respectively. Physicians considered it in 36% and 6% of cases, respectively, thereby misclassifying 134 patients (43%). The agreement between the HAS definition and the physicians' judgment was very low (κ = 0.30). Most of the patients who were identified as severely malnourished received no nutritional support. Performance status and pancreatic and gastric cancers were independently associated with malnutrition. Malnutrition levels are high, around 50%, unequally distributed according to the primitive tumor. It is still underestimated by physicians. Weight loss remains a clinically relevant, simple, and reliable marker of malnutrition.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The hemoglobin of Synechococcus sp. PCC 7002, GlbN, is a monomeric group I truncated protein (TrHb1) that coordinates the heme iron with two histidine ligands at neutral pH. One of these is the ...distal histidine (His46), a residue that can be displaced by dioxygen and other small molecules. Here, we show with mutagenesis, electronic absorption spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy that at high pH and exclusively in the ferrous state, Lys42 competes with His46 for the iron coordination site. When b heme is originally present, the population of the lysine-bound species remains too small for detailed characterization; however, the population can be increased significantly by using dimethyl-esterified heme. Electronic absorption and NMR spectroscopies showed that the reversible ligand switching process occurs with an apparent pK a of 9.3 and a Lys-ligated population of ∼60% at the basic pH limit in the modified holoprotein. The switching rate, which is slow on the chemical shift time scale, was estimated to be 20–30 s–1 by NMR exchange spectroscopy. Lys42–His46 competition and attendant conformational rearrangement appeared to be related to weakened bis-histidine ligation and enhanced backbone dynamics in the ferrous protein. The pH- and redox-dependent ligand exchange process observed in GlbN illustrates the structural plasticity allowed by the TrHb1 fold and demonstrates the importance of electrostatic interactions at the heme periphery for achieving axial ligand selection. An analogy is drawn to the alkaline transition of cytochrome c, in which Lys–Met competition is detected at alkaline pH, but, in contrast to GlbN, in the ferric state only.
Irinotecan is a powerful anticancer drug with severe systemic side effects that limit its clinical application. Drug-targeted delivery with noninvasive methods is required to enhance the drug ...concentration locally and to reduce these undesirable events. Microbubble-assisted ultrasound has become a promising method for noninvasive targeted drug delivery. The aim of this study is to evaluate the therapeutic effectiveness of in vitro and in vivo irinotecan delivery based on the combination of ultrasound and microbubbles. In the present study, in vitro results showed that the irinotecan treatment with microbubble-assisted ultrasound induced a significant decrease in cell viability of human glioblastoma cells. Moreover, using subcutaneous glioblastoma xenografts, the in vivo preclinical study in nude mice demonstrated that this therapeutic protocol led to a decrease in tumor growth and perfusion and an increase of tumor necrosis. The conclusions drawn from this study demonstrate the promising potential of this therapeutic approach for the anticancer targeted therapy.
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