Mutation of the RET protooncogene in sporadic medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) occurs sporadically or as part of the inherited cancer syndrome multiple endocrine neoplasia (MEN) type 2. In MEN 2A, germline missense mutations are found in one of five cysteine codons within exons 10 and 11 in the extracellular domain of the RET protooncogene. In MEN 2B, germline mutations occur in codon 918 (exon 16) within the catalytic core of the tyrosine kinase domain. To determine if RET mutations similar to those in MEN 2A and 2B play a role in the pathogenesis of sporadic MTC, we analysed 71 sporadic tumours comprising 68 primary tumours and three cell lines, for mutations in RET exons 10, 11, and 16. We found that 23% of sporadic MTC had RET codon 918 mutations, while only 3% had exon 10 mutations, and none had mutations in exon 11. We found no exon 16 mutations in MTC from 14 MEN 2A cases. Thus, exon 10 and 11 mutations, commonly found in familial MTC and MEN 2A, rarely occur in sporadic MTC; somatic mutation of RET codon 918 appears to play a role in the tumourigenesis of a significant minority of sporadic MTC but not MEN 2A tumours. In addition to their biological interest, these findings may have some clinical application in determining whether a patient presenting with isolated MTC is truly sporadic or is part of an inherited cancer syndrome.     

Constipation, polyps, or cancer? Let PTEN predict your future

The inherited hamartoma polyposis syndromes encompass several distinct clinical syndromes with different genetic bases, Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), juvenile polyposis syndrome (JPS), and Peutz-Jeghers syndrome (PJS). Germline mutations in PTEN, encoding a tumor suppressor phosphatase on 10q23.3, is associated with 80% of CS and 60% of BRRS. JPS is caused by mutations in MADH4 and BMPR1A, encoding two members of the TGFB superfamily. Germline mutations in LKB1 (STK11) are associated with a subset of PJS. The number, distribution, and histologic type of polyps differ amongst these syndromes as do component cancer risks. While rare, usually asymptomatic, hamartomatous polyps are felt to be component to CS. Hamartomatous polyposis is usually prominent and symptomatic in BRRS. Polyposis, which can be quite symptomatic, is a cardinal component feature of PJS and JPS. Interestingly, glycogenic acanthosis of the esophagus is highly predictive of CS and the presence of PTEN mutation. PTEN mutation positive CS have been shown to be at increased risk of breast, thyroid, and endometrial cancer. PTEN mutation positive BRRS are at increased risk of at least breast cancer, possibly that of the thyroid as well. In contrast, JPS and PJS have increased risk of gastrointestinal cancers in particular. Thus, molecular-based diagnoses to differentiate each of these syndromes are important for medical management.     

Frequency of germline genomic homozygosity associated with cancer cases

Guillaume Assié, MD, PhD; Thomas LaFramboise, PhD; Petra Platzer, PhD; Charis Eng, MD, PhD

JAMA. 2008;299(12):1437-1445.

Context  Cancer is a multigenic disease resulting from both germline susceptibility and somatic events. While studying loss of heterozygosity (LOH) in cancer tissues, we anecdotally observed a low frequency of heterozygosity in cancer patients compared with controls, raising the question whether homozygosity could play a role in cancer predisposition.

Objectives  To determine the frequency of germline homozygosity in a large series of patients with 3 different types of solid tumors compared with population-based controls.

Design, Setting, and Patients  Germline and corresponding tumor DNA isolated from 385 patients with carcinomas (147 breast, 116 prostate, and 122 head and neck carcinomas) were subjected to whole genome (345-microsatellite marker) LOH analysis.

Main Outcome Measures  Frequency of homozygosity at microsatellite markers in cancer cases vs controls and frequency of somatic LOH in cancers at loci with the highest homozygosity.

Results  We identified 16 loci in common among the 3 cancer types, with significantly increased germline homozygosity frequencies in the cancer patients compared with controls (P < .001). In the cases who happened to be germline heterozygous at these 16 loci, we found a mean (SD) LOH frequency of 58% (4.2%) compared with 50% (7.5%) at 197 markers without increased germline homozygosity (P < .001). Across the genome, this relationship holds as well (r = 0.46; 95% confidence interval, 0.37-0.53; P < .001). We validated the association of specific loci with high germline homozygosity frequencies in an independent, single-nucleotide polymorphism–based, public data set of 205 lung carcinomas from white individuals (P < .05 to P < .001) as well as the correlation between genome-wide germline homozygosity and LOH frequencies (r = 0.21; 95% confidence interval, 0.18-0.24; P < .001).

Conclusions  In our study of 4 different types of solid tumors (our data for 3 types validated in a fourth type), increased germline homozygosity occurred at specific loci. When the germline was heterozygous at these loci, high frequencies of LOH/allelic imbalance occurred at these loci in the corresponding carcinomas.

     

Targeting Neovasculature with Multitargeted Antiangiogenesis Tyrosine Kinase Inhibitors in Non-small Cell Lung Cancer

Chemotherapy has reached a plateau in the efforts for survival improvement in non-small cell lung cancer (NSCLC). The growing knowledge of NSCLC molecular pathobiology has led to the development of new treatments that target specific tumor functions. Angiogenesis is a tumor function leading to the formation of new tumor vessels that are crucial for its survival. Although vascular endothelial growth factor (VEGF) plays a primary role in angiogenesis, the inhibition of the VEGF pathway with VEGF-receptor (VEGFR) tyrosine kinase inhibitors (TKIs) is associated with a modest survival benefit due to the development of resistance by the tumor that has been mainly attributed to the up-regulation of other stimulators of angiogenesis. Thus, the use of multitargeted antiangiogenesis TKIs (MATKIs) for simultaneous inhibition of multiple angiogenic pathways has been proposed. This review summarizes data about novel treatment strategies incorporating the inhibition of angiogenesis with MATKIs in NSCLC. The data from all relevant studies shows that MATKIs do not offer additional survival benefit to currently available chemotherapeutic options in unselected NSCLC patients. However, the diversity in disease response to MATKI-containing regimens implies that specific patient subgroups may benefit from or be harmed by these agents. In this context, most studies agree that the VEGFR-targeting MATKIs are harmful in squamous NSCLC while specific MATKIs (i.e., motesanib, vandetanib and nintedanib) are associated with improved progression free survival in non-squamous NSCLC. However, overall survival benefit was found only in adenocarcinoma and Asian non-squamous NSCLC patients with the use of nintedanib and motesanib, respectively.     

Pressure support ventilation in adult respiratory distress syndrome: Short-term effects of a servocontrolled mode

: To assess the short-term effects of pressure support ventilation in adult respiratory distress syndrome (ARDS), we studied 17 patients with moderate to severe ARDS using mandatory rate ventilation (MRV), a servocontrolled mode of PSV having respiratory rate as the targeted parameter.: Based on the duration of ARDS, the patients were divided into two groups: Group 1, early ARDS (duration up to 1 week), 10 patients; Group 2, intermediate ARDS (duration between 1 and 2 weeks). The patients were initially ventilated with assisted mechanical ventilation then with MRV, and finally with controlled mechanical ventilation. After a 20-minute period allowed for stabilization in each mode, ventilatory variables, gas exchange, hemodynamics, and patient's inspiratory effort were evaluated.: During MRV blood gases, airway pressures and hemodynamic variables remained within acceptable limits in all patients. Compared with assisted mechanical ventilation, during MRV, patients of group 1 decreased their Vt and V? (from 0.64 ± 0.04 to 0.42 ± 0.03 L/sec) and increased their Ti/Tt (from 0.39 ± 0.03 to 0.52 ± 0.03). f did not change. PAO₂ - PaO₂ and Q?s/Q?t decreased (from 306 ± 16 to 269 ± 15 mm Hg, and from 20.2 ± 1.4 to 17.5 ± 1.1, respectively), while PaCO₂ increased (from 44 ± 3 to 50 ± 3 mm Hg). On the contrary, patients of group 2 increased their Vt (from 0.69 ± 0.02 to 0.92 ± 0.09 L), decreased their f (from 22.3 ± 0.5 to 19.3 ± 0.3 b/min), although they did not change their V? and Ti/Tt. PAO₂ - PaO₂ and Q?s/Q?t remained stable. PaCO₂ diminished (from 39 ± 3 to 34 ± 3 mm Hg). Pressure support level was higher in group 2 than in group 1 (29.4 ± 3.0 v 19.8 ± 2.9 cm H₂O).: We conclude that (1) PSV delivered by MRV may adequately ventilate patients with moderate to severe ARDS, preserving gas exchange and hemodynamics, at least for the short period tested; (2) early and intermediate ARDS respond in a different manner to MRV in terms of breathing pattern, gas exchange, and level of pressure assistance; and (3) patients with early ARDS are those who have an improvement in intrapulmonary oxygenation probably due, at least in part, to alveolar recruitment augmented by active diaphragmatic contraction.     

Novel assays of thrombogenic pathogenicity in the antiphospholipid syndrome based on the detection of molecular oxidative modification of the major autoantigen β2‐glycoprotein I

Objective

Beta‐2‐glycoprotein I (β₂GPI) constitutes the major autoantigen in the antiphospholipid syndrome (APS), a common acquired cause of arterial and venous thrombosis. We recently described the novel observation that β₂GPI may exist in healthy individuals in a free thiol (biochemically reduced) form. The present study was undertaken to quantify the levels of total, reduced, and posttranslationally modified oxidized β₂GPI in APS patients compared to various control groups.

Methods

In a retrospective multicenter analysis, the proportion of β₂GPI with free thiols in serum from healthy volunteers was quantified. Assays for measurement of reduced as well as total circulating β₂GPI were developed and tested in the following groups: APS (with thrombosis) (n = 139), autoimmune disease with or without persistent antiphospholipid antibodies (aPL) but without APS (n = 188), vascular thrombosis without APS or aPL (n = 38), and healthy volunteers (n = 91).

Results

Total β₂GPI was significantly elevated in patients with APS (median 216.2 μg/ml [interquartile range 173.3–263.8]) as compared to healthy subjects (median 178.4 μg/ml [interquartile range 149.4–227.5] [P < 0.0002]) or control patients with autoimmune disease or vascular thrombosis (both P < 0.0001). The proportion of total β₂GPI in an oxidized form (i.e., lacking free thiols) was significantly greater in the APS group than in each of the 3 control groups (all P < 0.0001).

Conclusion

This large retrospective multicenter study shows that posttranslational modification of β₂GPI via thiol‐exchange reactions is a highly specific phenomenon in the setting of APS thrombosis. Quantification of posttranslational modifications of β₂GPI in conjunction with standard laboratory tests for APS may offer the potential to more accurately predict the risk of occurrence of a thrombotic event in the setting of APS.

     

Short progression-free survival predicts for poor overall survival in older patients with multiple myeloma treated upfront with novel agent-based therapy

Objectives: To assess the importance of the quality of response and of early relapse in unselected elderly patients with myeloma treated upfront with novel agents. Methods: We analyzed 135 unselected transplant‐ineligible patients older than 65 yr who were treated upfront with novel agent‐based regimens in a single center. Results: On intent to treat, 81% of patients achieved a response (28% sCR/CR, 23% VGPR, and 30% PR). Median progression‐free survival (PFS) for patients who achieved sCR/CR was 31 vs. 20 months for VGPR and 23 months for PR (P = 0.048). Median overall survival (OS) for patients with sCR/CR was 62 months, 53 months for VGPR and 38 months for patients with PR (P = 0.028). Early relapse (PFS < 12 months) was more common in patients with PR (39% vs. 21% for VGPR vs. 3% for sCR/CR). Patients who relapsed or progressed <12 months from initiation of treatment had a median OS of 15.4 months compared with 53 months (P < 0.001) for patients who had a PFS > 12 months despite the fact that after relapse or progression most patients were treated again with novel agents. In multivariate analysis, short PFS was the most significant adverse prognostic factor affecting OS, associated with a 7.25‐fold (P < 0.0001) increase in the risk of death. Conclusion: In newly diagnosed patients over 65 yr, treated upfront with novel agents achievement of CR and a PFS ≥12 months is associated with improved outcome. Patients who fail to respond or experience early relapse after primary therapy with novel agent‐based regimens should be encouraged to participate in clinical trials of novel agents and combinations.     

Hemoglobin, erythropoietin and systemic inflammation in exacerbations of chronic obstructive pulmonary disease

Background

Systemic inflammation may represent a possible cause of anemia. Previous data support that anemic patients with COPD present high erythropoietin (EPO) levels, suggestive of EPO resistance, possibly mediated through inflammatory mechanisms.

Objectives

We aimed to determine whether systemic inflammation, which is usually up-regulated during exacerbations of COPD (ECOPD) is associated with low hemoglobin levels expressing erythropoietin resistance.

Methods

Hemoglobin (Hb), EPO and serum biomarkers of systemic inflammation [CRP, TNF-α, fibrinogen and IL-6] were assessed at three time points (admission, resolution and stable phases) in a selected cohort of 93 COPD patients.

Results

Hemoglobin levels were significantly lower on admission compared to resolution and stable phases (median 12.1 g/dl [interquartile ranges 11.2-12.7], vs 13.5 [12.4-14.3] vs 13.4 [12.7-14.08], respectively p = 0.002), whereas EPO was significantly higher on admission compared to resolution and stable phases. A negative association between Hb and IL-6 and a positive association between EPO and IL-6 were observed only during the acute phase of exacerbation. EPO and Hb were negatively associated during the acute phase, whereas they were positively associated during discharge and stable phase.

Conclusions

In this observational study we have shown that during admission for ECOPD Hb levels are decreased and EPO levels are increased. We have also identified a negative association between Hb and EPO. The above association is mainly related to increased IL-6 levels, indicating a possible EPO resistance through the mechanism of increased systemic inflammatory process.