OBJECTIVE: A review of the literature on Tregs in acute leukaemias was conducted and Tregs were determined in B-cell acute lymphoblastic leukaemias (ALLs).
RESULTS: Studies on Tregs in B-cell ALL are few and controversial. We observed a significantly increased percentage of Tregs (mean±SD, 9.72 ± 3.79% vs. 7.05 ± 1.74%; P = 0.047) in the bone marrow/peripheral blood of ALL (n = 17) compared to peripheral blood of normal controls (n = 35). A positive trend between Tregs and age (R = 0.474, P = 0.055, n = 17) implicates this factor of poor prognosis in B-cell ALL.
DISCUSSION: Tregs in cancer are particularly significant in immunotherapy. The manipulation of the immune system to treat cancer has for a long time ignored regulatory mechanisms inducible or in place. In lymphoma studies, tumour-specific mechanisms that are unlike conventional methods in the induction of Tregs have been hypothesized. In addition, tumour-infiltrating Tregs may present different profiles from peripheral blood pictures. Tregs will continue to be dissected to reveal its mysteries and their impact on clinical significance.
METHOD: By using the keywords "acute lymphoblastic leukemia", and "microarray", a total of 280 and 275 microarray datasets were found listed in Gene Expression Omnibus database GEO and ArrayExpress database respectively. Further manual inspection found that only three studies (GSE18497, GSE28460, GSE3910) were focused on gene expression profiling of paired diagnosis-relapsed pediatric B-ALL. These three datasets which comprised of a total of 108 matched diagnosis-relapsed pediatric B-ALL samples were then included for this meta-analysis using RankProd approach.
RESULTS: Our analysis identified a total of 1795 upregulated probes which corresponded to 1527 genes (pfp 1), and 1493 downregulated probes which corresponded to 1214 genes (pfp cell cycle processes (enrichment score = 15.3), whilst the downregulated genes were clustered in transcription regulation (enrichment score = 12.6). Elevated expression of cell cycle regulators (e.g kinesins, AURKA, CDKs) was the key genetic defect implicated in relapsed ALL, and serve as attractive targets for therapeutic intervention.
CONCLUSION: We identified S100A8 as the most overexpressed gene, and the cell cycle pathway as the most promising biomarker and therapeutic target for relapsed childhood B-ALL. The validity of the results warrants further investigation.
METHODS: We used semi-quantitative reverse-transcriptase PCR (RT-PCR) and Western blot to investigate the expression of full length p53 (TAp53), Delta40p53, Delta133p53 or p53beta in diagnostic marrow from a clinical cohort of 50 BCP-ALL patients without TP53 mutation (29 males and 21 females, age range 2-14 years) and in the bone marrow cells of 4 healthy donors (used as controls).
RESULTS: Irrespective of isoforms, levels of p53 mRNA were low in controls but were increased by 2 to 20-fold in primary or relapse BCP-ALL. TAp53 was increased in primary BCP-ALL, Delta40p53 was elevated in relapse BCP-ALL, whereas Delta133p53 and p53beta were increased in both. Next, mRNA levels were used as a basis to infer the ratio between protein isoform levels. This inference suggested that, in primary BCP-ALL, p53 was predominantly in active oligomeric conformations dominated by TAp53. In contrast, p53 mostly existed in inactive quaternary conformations containing ≥2 Delta40 or Delta133p53 in relapse BCP-ALL. Western blot analysis of blasts from BCP-ALL showed a complex pattern of N-terminally truncated p53 isoforms, whereas TAp53beta was detected as a major isoform. The hypothesis that p53 is in an active form in primary B-ALL was consistent with elevated level of p53 target genes CDKN1A and MDM2 in primary cases, whereas in relapse BCP-ALL, only CDKN1A was increased as compared to controls.
CONCLUSION: Expression of p53 isoforms is deregulated in BCP-ALL in the absence of TP53 mutation, with increased expression of alternative isoforms in relapse BCP-ALL. Variations in isoform expression may contribute to functional deregulation of the p53 pathway in BCP-ALL, specifically contributing to its down-regulation in relapse forms.
METHODS: We randomised 429 children with newly diagnosed ALL to 15-minute vs 3-hour infusion for the first dose of VCR to study if prolonging the first dose of VCR infusion improved response. In a subgroup of 115 B-ALL and 20 T-ALL patients, we performed VCR plasma (n = 135 patients) and intracellular (n = 66 patients) pharmacokinetic studies. The correlations between pharmacokinetic parameters and intracellular VCR levels with early treatment response, final outcome and ABCB1 genotypes were analysed.
RESULTS: There was no significant difference between 15-minute and 3-hour infusion schedules in median Day 8 peripheral or bone marrow blast response. Plasma VCR pharmacokinetic parameters did not predict outcome. However, in B-ALL, Day 33 minimal residual disease (MRD) negative patients and patients in continuous complete remission had significantly higher median intracellular VCR24h levels (P = .03 and P = .04, respectively). The median VCR24h intracellular levels were similar among the common genetic subtypes of ALL (P = .4). Patients homozygous for wild-type ABCB1 2677GG had significantly higher median intracellular VCR24h (P = .04) than 2677TT.
CONCLUSION: We showed that in childhood B-ALL, the intracellular VCR24h levels in lymphoblasts affected treatment outcomes. The intracellular VCR24h level was independent of leukaemia subtype but dependent on host ABCB1 G2677T genotype.
STUDY DESIGN: An observational study.
PLACE AND DURATION OF STUDY: Pediatric Oncology Ward, Shaukat Khanum Cancer Hospital, Lahore, from January 2015 to July 2017.
METHODOLOGY: Patients aged 1-15 years, diagnosed with ALL, were included. Studied variables were cytogenetic type and MRD outcome in patients with ALL. Patients under one year of age and more than 15 years, or those having comorbidities, were excluded.
RESULTS: Total 150 patients' data were retrieved from the Hospital database. One hundred and thirty-three belonged to age 1 to 5 years group (89%) and 17 (11%) were in 5 to 10 years group. The mean age of the patient was 4.3 +3.1 years. One hundred and two (68%) were males; whereas, 48 (32%) were females. Pre B acute lymphoblastic leukemia was diagnosed in 139 (93%) patients and 11(7%) were diagnosed with Pre T acute lymphoblastic leukemia. Standard risk was observed in 120 (80%) patients and 30 (20%) patients were on high risk as per National Cancer Institute (NCI) Guidelines. Regimen A was used in 125 (83.3%), Regimen B in 16 (10.7%), and Regimen C in 9 (6%) patients. BCR-ABL was positive in 2 (1.30%), TEL-AML in 68 (45%), MLL in 5 (3.30%), and normal in 54 (36%). MRD at day 29 was negative in 40 (93%) and positive in 3 (7%). The karyotyping was done in 128 (85%) patients, out of which 68 (53%) were hyperploids, 41 (32%) euploid, and 19 (15%) were hypoploid. Death was observed in 22 (15%) patients. Nineteen (86%) deaths were due to fungal and bacterial sepsis; and disease-related deaths were noted in 3 (14%) patients.
CONCLUSION: The role of MRD and cytogenetics in risk assessment has improved in the early prognosis determination.