BCR-ABL1 kinase domain mutations may persist at very low levels for many years and lead to subsequent TKI resistance.

BACKGROUND: BCR-ABL1 mutation analysis is recommended for chronic myeloid leukaemia patients. However, mutations may become undetectable after changing therapy, and it is unknown whether they have been eradicated. METHODS: We examined longitudinal data of patients with imatinib-resistant mutations, which became undetectable by Sanger sequencing to determine whether mutations could reappear, and the related circumstances. RESULTS: Identical imatinib- and nilotinib-resistant mutations reappeared following further therapy changes in five patients, and was associated with subsequent nilotinib resistance in four. CONCLUSION: The data suggest that some BCR-ABL1 mutations may persist at undetectable levels for many years after changing therapy, and can be reselected and confer resistance to subsequent inhibitors.

Essential, but at what risk? A prospective study on central venous access in patients with haematological malignancies.

AIMS: Central venous catheters (CVC) are integral to modern haematology practice; however, they are associated with a range of complications. This prospective study aimed to determine the rate of CVC-related complications and risk factors in haematology patients, who are vulnerable because of their underlying pathology and treatments. METHODS: All inpatients that had a non-tunnelled CVC inserted in a 14-month period in the haematology ward at St Vincent's Hospital were enrolled. Complications (immediate and late), demographics, type of device, insertion technique and duration of dwell, were examined using multivariate analysis. RESULTS: One hundred and seventy-four CVC in 84 patients were recorded, representing 3016 catheter-days. At least one complication was found in 43 (24.7%) patients. Immediate complications occurred in 13 (7.5%) insertions, with a higher rate in those inserted after ≥2 attempts compared with one (P = 0.02). Catheter-related bloodstream infection occurred at a rate of 7.6 per 1000 catheter-days, with acute lymphoblastic leukaemia associated with a higher rate (P = 0.02), and subclavian vein CVC had a lower rate compared with other locations (P < 0.01). Thrombosis was found in seven (4.0%) patients, with subclavian CVC carrying an increased risk (P = 0.02). CONCLUSIONS: This prospective observational study found almost a quarter of haematology patients experience a CVC-related complication. An association was found with a number of attempts at insertion and immediate complications; other risk factors included anatomical location, underlying disease and duration of catheterisation. The relatively high complication rate, compared with reports of non-haematology patients, highlights the need to improve CVC management, a vital part of care for this population.

Differential effects on gene transcription and hematopoietic differentiation correlate with GATA2 mutant disease phenotypes.

Heterozygous GATA2 mutations underlie an array of complex hematopoietic and lymphatic diseases. Analysis of the literature reporting three recurrent GATA2 germline (g) mutations (gT354M, gR396Q and gR398W) revealed different phenotype tendencies. Although all three mutants differentially predispose to myeloid malignancies, there was no difference in leukemia-free survival for GATA2 patients. Despite intense interest, the molecular pathogenesis of GATA2 mutation is poorly understood. We functionally characterized a GATA2 mutant allelic series representing major disease phenotypes caused by germline and somatic (s) mutations in zinc finger 2 (ZF2). All GATA2 mutants, except for sL359V, displayed reduced DNA-binding affinity and transactivation compared with wild type (WT), which could be attributed to mutations of arginines critical for DNA binding or amino acids required for ZF2 domain structural integrity. Two GATA2 mutants (gT354M and gC373R) bound the key hematopoietic differentiation factor PU.1 more strongly than WT potentially perturbing differentiation via sequestration of PU.1. Unlike WT, all mutants failed to suppress colony formation and some mutants skewed cell fate to granulocytes, consistent with the monocytopenia phenotype seen in GATA2-related immunodeficiency disorders. These findings implicate perturbations of GATA2 function shaping the course of development of myeloid malignancy subtypes and strengthen complete or nearly complete haploinsufficiency for predisposition to lymphedema.

The clinical significance of ABCB1 overexpression in predicting outcome of CML patients undergoing first-line imatinib treatment.

Tyrosine kinase inhibitor (TKI) therapy results in excellent responses in the majority of patients with chronic myeloid leukaemia. First-line imatinib treatment, with selective switching to nilotinib when patients fail to meet specific molecular targets or for imatinib intolerance, results in excellent overall molecular responses and survival. However, this strategy is less effective in cases of primary imatinib resistance; moreover, 25% of patients develop secondary resistance such that 20-35% of patients initially treated with imatinib will eventually experience treatment failure. Early identification of these patients is of high clinical relevance. Since the drug efflux transporter ABCB1 has previously been implicated in TKI resistance, we determined if early increases in ABCB1 mRNA expression (fold change from diagnosis to day 22 of imatinib therapy) predict for patient response. Indeed, patients exhibiting a high fold rise (⩾2.2, n=79) were significantly less likely to achieve early molecular response (BCR-ABL1IS ⩽10% at 3 months; P=0.001), major molecular response (P<0.0001) and MR4.5 (P<0.0001). Additionally, patients demonstrated increased levels of ABCB1 mRNA before the development of mutations and/or progression to blast crisis. Patients with high fold rise in ABCB1 mRNA were also less likely to achieve major molecular response when switched to nilotinib therapy (49% vs 82% of patients with low fold rise). We conclude that early evaluation of the fold change in ABCB1 mRNA expression may identify patients likely to be resistant to first- and second-generation TKIs and who may be candidates for alternative therapy.

TGF-α and IL-6 plasma levels selectively identify CML patients who fail to achieve an early molecular response or progress in the first year of therapy.

Early molecular response (EMR, BCR-ABL1 (IS)⩽10% at 3 months) is a strong predictor of outcome in imatinib-treated chronic phase chronic myeloid leukemia (CP-CML) patients, but for patients who transform early, 3 months may be too late for effective therapeutic intervention. Here, we employed multiplex cytokine profiling of plasma samples to test newly diagnosed CP-CML patients who subsequently received imatinib treatment. A wide range of pro-inflammatory and angiogenesis-promoting cytokines, chemokines and growth factors were elevated in the plasma of CML patients compared with that of healthy donors. Most of these normalized after tyrosine kinase inhibitor treatment while others remained high in remission samples. Importantly, we identified TGF-α and IL-6 as novel biomarkers with high diagnostic plasma levels strongly predictive of subsequent failure to achieve EMR and deep molecular response, as well as transformation to blast crisis and event-free survival. Interestingly, high TGF-α alone can also delineate a poor response group raising the possibility of a pathogenic role. This suggests that the incorporation of these simple measurements to the diagnostic work-up of CP-CML patients may enable therapy intensity to be individualized early according to the cytokine-risk profile of the patient.

Early computed tomography features in extensive middle cerebral artery territory infarct: prediction of survival.

BACKGROUND: To assess the predictive value of prognosis of different computed tomography (CT) features and National Institutes of Health Stroke Scale score (NIHSS) in acute extensive middle cerebral artery (MCA) infarct. METHODS: Fifty five patients with acute extensive MCA infarct had the CT performed within 24 hours of the onset of symptoms. A total of 11 CT features were analysed. The age distribution, presence of risk factors, presence of individual CT feature, the total CT score, and the NIHSS were correlated with the 30 day mortality. RESULTS: Single explanatory variable analysis showed NIHSS, presence of midline shift, midline shift of more than 1 cm, extent of infarct, presence of hydrocephalus, effacement of subarachnoid space/cella media, attenuation of corticomedullary differentiation, and total CT score were associated with the 30 day mortality. Both extent of infarct >67% and attenuation of corticomedullary differentiation gave a sensitivity and specificity of 93% and 95%, respectively, for the prediction of survival. Logistic regression analysis showed that the extent of infarct and NIHSS were the only independent predictors. CONCLUSIONS: CT features and admission NIHSS are important parameters for prediction of survival in extensive MCA infarct.

Imaging features of hepatocellular carcinoma.

This pictorial review concentrates on the imaging features of hepatocellular carcinoma as revealed by ultrasonography, computed tomography, magnetic resonance imaging and angiography. Understanding of the pathomorphological characteristics of the disease is important to precise image interpretation.

Impact of changes in respiratory frequency and posture on power spectral analysis of heart rate and systolic blood pressure variability in normal subjects and patients with heart failure.

1. Autonomic dysfunction is a major feature of congestive cardiac failure and may have an important role in determining progression and prognosis. The low-frequency/high-frequency ratio derived from power spectral analysis of heart rate variability has been proposed as a non-invasive method to assess sympatho-vagal balance. However, the effects of different respiratory rates or posture are rarely accounted for, but may be relevant in patients with heart failure in whom clinical improvement is accompanied by a fall in respiratory rate and an increased proportion of the day in the upright position. 2. We have assessed the effect of controlled respiration at different rates (10, 15, 20 breaths/min or 0.17, 0.25 and 0.33 Hz), while supine and standing, on power spectral analysis of heart rate and blood pressure variability in 11 patients with heart failure and 10 normal subjects. 3. Heart rate variance and low-frequency power (normalized units) were reduced in patients with heart failure (absent in six). During controlled breathing while supine, the power of the high-frequency component was significantly greater at 10 breaths/min than at 20 breaths/min in patients with heart failure, whether expressed in absolute units (P = 0.005) or percentage of total power (P = 0.03). 4. On standing, controlled breathing in patients with heart failure produced less change in high-frequency power (P = 0.054), but the low-frequency/high-frequency ratio at lower respiratory rates was reduced (P = 0.05). In normal subjects, as expected, respiratory rate had a highly significant effect on high-frequency power. Also, in normal subjects there was the expected increase in heart rate low-frequency power (P = 0.04) moving from supine to standing with an increase in the low-frequency/high-frequency ratio (P = 0.003), while in the patients with heart failure this was absent, reflecting blunted cardiovascular reflexes. 5. Systolic blood pressure low- and high-frequency components and their ratio were significantly affected by respiration (P < 0.03) and change in posture (P < 0.03) in both patients with heart failure and normal subjects, with a significant increase in the low-frequency/high-frequency ratio (P = 0.03) on standing in patients with heart failure, indicating that autonomic modulation of blood pressure is still operating in heart failure. 6. Thus, respiratory rate and changes in posture have a significant effect on measurements derived from spectral analysis of heart rate and blood pressure variability. Studies that use power spectral analysis as a measure of sympatho-vagal balance should control for these variables.