Mechanisms of relapse in acute leukaemia: involvement of p53 mutated subclones in disease progression in acute lymphoblastic leukaemia

Mutations of the p53 tumour suppressor gene are infrequent at presentation of both acute myeloblastic leukaemia (AML) and acute lymphoblastic leukaemia (ALL), being found in between 5-10% of AML and 2-3% of ALL. Here we have studied the frequency of detection of p53 mutations at relapse of both AML and B-precursor ALL. In those patients with detectable mutations at relapse we investigated whether the mutation was detectable at presentation and was thus an early initiating event or whether it had arisen as a late event associated with relapse. Bone marrow samples from 55 adults and children with relapsed AML (n = 41) or ALL (n = 14) were analysed for p53 gene alterations by direct sequencing of exons 5-9. For samples where a p53 mutation was found at relapse, analysis of presentation samples was carried out by direct sequencing of the exon involved, or by allele-specific polymerase chain reaction (PCR) if the mutation could not be detected using direct sequencing. A p53 mutated gene was found at relapse in seven out of 55 cases. The frequency was higher in relapsed ALL (four out of 14 cases; 28.6%) compared to AML (three out of 41 cases; 7.3%). In five out of the seven cases presentation samples were available to study for the presence of the mutation. In two out of two AML patients the p53 mutation was detectable in the presentation sample by direct sequencing. In three ALL patients analysis of presentation material by direct sequencing showed a small mutant peak in one case, the other two being negative despite the sample analysed containing > 90% blast cells. However in both of these patients, the presence of p53 mutation was confirmed in the presentation sample using allele-specific PCR. In one of these patients the emergence of a subclone at relapse was confirmed by clonality analysis using IgH fingerprinting. Our results confirm that in ALL p53 mutations are present in a proportion of patients at relapse. Furthermore cells carrying the mutation are detectable at presentation in a minor clone suggesting that p53 mutations in ALL may be a mechanism contributing to disease relapse.     

Pulmonary function after treatment for acute lymphoblastic leukaemia in childhood.

The aim of this study was to examine pulmonary function after acute lymphoblastic leukaemia in childhood and identify risk factors for reduced pulmonary function. We studied a population-based cohort of 94 survivors of acute lymphoblastic leukaemia in childhood who were in first remission after treatment without spinal irradiation or bone marrow transplantation. Pulmonary function test results were compared with reference values for our laboratory, based on 348 healthy subjects who had never smoked from a local population study. A median of 8 years after cessation of therapy (range 1-18 years) the participants had a slight, subclinical, restrictive ventilatory insufficiency and reduced transfer factor and transfer coefficient. The changes in lung function were related to younger age at treatment and to more dose-intensive treatment protocols that specified more use of cranial irradiation and higher cumulative doses of anthracyclines, cytosine arabinoside and intravenous cyclophosphamide than previous protocols. We conclude that, 8 years after treatment without bone marrow transplantation or spinal irradiation, survivors of childhood acute lymphoblastic leukaemia in first remission were without pulmonary symptoms but had signs of slight restrictive pulmonary disease including reduced transfer factor. The increased dose intensity of many recent protocols for childhood acute lymphoblastic leukaemia may lead to increased late pulmonary toxicity.     

Glucocorticoid use in acute lymphoblastic leukaemia

Glucocorticoids (prednisone and dexamethasone) play an essential part in the treatment of acute lymphoblastic leukaemia (ALL), but their optimum doses and bioequivalence have not been established. Results of preclinical studies have shown that dexamethasone has a longer half-life and better CNS penetration than does prednisone. In prospective randomised trials, dexamethasone improved control of CNS leukaemia. At a prednisone-to-dexamethasone dose ratio of less than seven, dexamethasone (6-18 mg/m(2) per day) resulted in a better event-free survival than did prednisone (40-120 mg/m(2) per day), and high-dose dexamethasone (10-18 mg/m(2) per day) improved the outcome of T-cell ALL and high-risk ALL. However, dexamethasone caused more adverse effects, including infection, bone fracture, osteonecrosis, mood and behaviour problems, and myopathy. At a dose ratio greater than seven, the two drugs showed no difference in efficacy. Therefore, the efficacy of prednisone and dexamethasone is dose dependent and needs to be carefully assessed against the toxic effects. Moreover, although dexamethasone generally showed increased activity in ALL cells in vitro, the dose ratio of the two drugs that exerted equivalent cytotoxic effects differed substantially in samples from individuals. The selection of the type and dose of glucocorticoid should be based on the risk of relapse, treatment phase, and the chemotherapeutic drugs used concomitantly.     

Testicular relapse in acute lymphoblastic leukaemia: studies with an experimental mouse model.

Neither testis nor epididymis was found to be invaded by L1210 leukaemic cells in spite of widespread dissemination through other organs and tissues. The same applied to animals in relapse after protracted remissions induced by cyclophosphamide. Prior damage to the gonadal vascular endothelium by Cd++ did enable leukaemic cells to enter the testicular interstitium, but not the depleted seminiferous tubules. Injection of cells into the lymphatic sinus system of the testis led to rapid peritubular proliferation and systemic dissemination but the seminiferous tubules were not penetrated. The histological appearance resembled that of human ALL. The results suggest that the L1210 system, using the intratesticular route for inoculation can be used to examine the susceptibility to drugs of leukaemic cells in this environment. The potential of drugs to damage the vascular endothelium of the gonad and perhaps contribute to the development of testicular relapse could be assessed following intramuscular inoculation of cells.     

A score at diagnosis for predicting length of remission in childhood acute lymphoblastic leukaemia.

Thirty-two variables at diagnosis of acute lymphoblastic leukaemia (ALL) were studied in an unselected population-bases series of 209 children. Twelve variables had individually a statistically significant effect on the duration of first remission. A multivariate analysis using data on the 199 children who went into complete remission showed that all significant variation in remission times could be explained by only 3 variables acting simultaneously. These were the total white blood count (WBC) at diagnosis, the Franco-American-British (FAB) classification of blast morphology and the percentage of lymphoblasts with PAS+ coarse granules or blocks. A simple scoring system (for WBC add 1 if less than 20 X 10(9)/1, add 2 if 20 - 50 X 10(9)/1, add 3 if greater than or equal to 50 X 10(9)/1; for L2 or L3 leukaemia add 1; for PAS+ less than 5% add 1) separated patients into risk groups with widely different median lengths of first remission. Application of the risk score improves the prediction of the outcome of treatment, and the clinical trials, allows more accurate stratification, less extensive data collection and simpler analysis.     

Haemopoietic stem cell transplantation for acute lymphoblastic leukaemia

The majority of children and some adults with acute lymphocytic leukaemia (ALL) can be cured with current intensive chemotherapy regimens. For those patients who relapse or who do not achieve remission, allogeneic haemopoietic stem cell transplantation (HSCT) offers the best chance for long-term disease control. Different sources of haemopoietic stem cells including marrow, peripheral blood, and cord blood are now available and the introduction of subablative regimens has increased the number of patients who are transplant candidates. Relapse remains the major cause of transplant failure and immunotherapy strategies post-transplant to augment the graft versus leukaemia effect are being explored.     

Spontaneous complete remission in acute lymphoblastic leukaemia

Case records of 78 patients of acute lymphoblastic leukemia have been reviewed. Complete remission occurred in seven cases following an episode of septicemia and supportive care.     

Bone-marrow relapse in paediatric acute lymphoblastic leukaemia

Marrow relapse is the major obstacle to cure for 10-15% of young patients with acute lymphoblastic leukaemia (ALL). Recent investigations into the biology of minimal residual disease indicate that many early relapses derive from residual cells present at first diagnosis, but some late relapses might represent new mutations in leukaemic cells not eliminated by conventional therapy. Treatment of marrow relapse involves higher doses and more intensive schedules of the drugs used for initial therapy with or without haemopoietic stem cell transplantation. In most reports, transplantation is better than continuation chemotherapy in early marrow relapse, but its role in later relapse is less clear. Current therapy cures 10% of patients with early marrow relapses and 50% of those with late relapses, but outcomes have changed little in the past two decades. Understanding the molecular biology of ALL underlies development of improved risk stratification and new therapies. Although better drugs are needed, introduction of new agents into clinical trials in paediatric disease has been difficult. Innovative trial designs and use of valid surrogate endpoints may expedite this process.     

SERUM metabolomics of acute lymphoblastic leukaemia and acute myeloid leukaemia for probing biomarker molecules

Acute leukaemia (AL) is a critical neoplasm of white blood cells. Diagnosing AL requires bone marrow puncture procedure, which many patients do not consent to for it is invasive. Hence sensitive and specific early diagnostic biomarkers are essential for non‐invasive diagnosis, new therapeutics and improving the disease prognosis. To differentiate the metabolic alterations associated with acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML), we investigated serum of ALL and AML patients in comparison with two controls using gas chromatography coupled with triple quadrupole tandem mass spectrometry and multivariate statistical analysis. Twenty seven out of 1425 metabolites were found differentiative among ALL, AML, aplastic anaemia (APA) patients and healthy control using p‐value ≤ 0.001. ALL is the most dissimilar group from other three groups as in hierarchical clustering showed 72.1% dissimilarity. Model generation using PLSDA gave an overall accuracy of 91.9%. This study helps in metabolic fingerprinting of control and disease serum at high significance levels and could be used for early diagnosing of AL. Based on pathways analysis, fatty acid metabolism is deregulated in patients with AL and may represent an underlying metabolic pathway associated with disease progression. Copyright © 2016 John Wiley & Sons, Ltd.