Absence of leukaemic fusion gene transcripts in preterm infants exposed to diagnostic x rays

Systematic Review of Normal Subjects Harbouring BCR-ABL1 Fusion Gene

The treatment of chronic myeloid leukaemia (CML) requires quantitative polymerase chain reaction (qPCR) to monitor BCR-ABL1 in International Scale (IS). Some normal subjects were found to harbour BCR-ABL1. We performed a systematic review on normal subjects harbouring BCR-ABL1. A literature search was done on July 16, 2017 using EBSCOhost Research Databases interface and Western Pacific Region Index Medicus. Two authors selected the studies, extracted the data, and evaluated the quality of studies using the modified Appraisal Tool for Cross-Sectional Studies independently. The outcomes were prevalence, level of BCR-ABL1IS, proportion, and time of progression to CML. The initial search returned 4,770 studies. Eleven studies, all having used convenient sampling, were included, with total of 1,360 subjects. Ten studies used qualitative PCR and one used qPCR (not IS). The mean prevalence of M-BCR was 5.9, 15.5, and 15.9% in cord blood/newborns/infants (CB/NB/I) (n = 170), children (n = 90), and adults (n = 454), respectively, while m-BCR was 15, 26.9, and 23.1% in CB/NB/I (n = 786), children (n = 67), and adults (n = 208), respectively. No study reported the proportion and time of progression to CML. Nine studies were graded as moderate quality, one study as poor quality, and one study as unacceptable. The result of the studies could neither be inferred to the general normal population nor compared. Follow-up data were scarce.

Exposure of extremely low birth weight infants to diagnostic X-Rays: a longitudinal study

AIM

To quantify the number of chest and abdominal radiograms performed in surviving singleton extremely low birth weight (ELBW) infants in order to examine whether changes in imaging application occurred during the last 21 years (1987-2007).

METHODS

Clinical and radiological data of 225 out of 229 surviving infants were obtained and associations with time and clinical variables were evaluated.

RESULTS

The number of chest X-Rays performed per infant was 10.3 +/- 11.1 (mean +/- SD), median = 7; range = 0-77 and the number of abdominal radiograms was 5.6 +/- 7.1, median = 3; range = 0-61. The number of chest and abdominal X-Rays performed per patient during 1987-1996 was very similar to that of 1997-2007, and no appreciable change of trend was observed along the years. There were negative and statistically significant correlations between the gestational age and the number of radiograms performed per patient (chest X-Rays: r =-0.402; p < 0.001, abdominal X-Rays: r =-0.182; p = 0.006). Controlling for gestational age, reduced numbers of radiograms per patient (abdominal: b =-1.20, p = 0.235; chest: b =-3.08, p = 0.035) were demonstrated in the second period. Patients with complicated clinical course were exposed to significantly more radiograms.

CONCLUSION

Controlling for gestational age, a reduced number of exposures to chest radiograms was demonstrated during 1997-2007 compared with 1987-1996. Measures to reduce radiation, especially in complicated cases, are advocated.

The Epidemiology of Childhood Leukemia with a Focus on Birth Weight and Diet

Leukemia is the most common childhood cancer and a major source of morbidity and mortality. The etiology of childhood leukemia remains largely unknown. Cytogenetic abnormalities determine disease subtypes, prognosis, clinical presentation, and course and may help in discovering etiological factors. Epidemiologic investigations of leukemia are complicated by many factors, including the rarity of the disease, necessitating careful study design. Two emerging areas of interest in leukemia etiology are birth weight and diet. High birth weight has been associated with increased risk of childhood leukemia. The biological mechanism behind this association may involve insulin-like growth factor I (IGF-I), which is associated with high birth weight. IGF-I may act by increasing the absolute number of stem cells available for transformation, stimulating the growth of cells that are already transformed, or a combination of effects. Diet has been linked with leukemia. Maternal dietary DNA topoisomerase II (DNAt2) inhibitor intake is associated with infant acute myeloid leukemia (AML) with the MLL gene translocation. Increased intake of fruits and vegetables has been associated with decreased leukemia risk and, relatedly, lack of maternal folate supplementation has been associated with increased childhood leukemia risk, possibly by causing DNA hypomethylation and increased DNA strand breaks. Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms modify this risk.

HLA-DPB1 supertype-associated protection from childhood leukaemia: relationship to leukaemia karyotype and implications for prevention

Most childhood B cell precursor (BCP) acute lymphoblastic leukaemia (ALL) cases carry the reciprocal translocation t(12;21)(p13;q22) ( approximately 25%), or a high hyperdiploid (HeH) karyotype (30%). The t(12;21) translocation leads to the expression of a novel fusion gene, TEL-AML1 (ETV6-RUNX1), and HeH often involves tri- and tetrasomy for chromosome 21. The presence of TEL-AML1+ and HeH cells in utero prior to the development of leukaemia suggests that these lesions play a critical role in ALL initiation. Based on our previous analysis of HLA-DP in childhood ALL, and evidence from in vitro studies that TEL-AML1 can activate HLA-DP-restricted T cell responses, we hypothesised that the development of TEL-AML1+ ALL might be influenced by the child's DPB1 genotype. To test this, we analysed the frequency of six HLA-DPB1 supertypes in a population-based series of childhood leukaemias (n = 776) classified by their karyotype (TEL-AML1+, HeH and others), in comparison with newborn controls (n = 864). One DPB1 supertype (GKD) conferred significant protection against TEL-AML1+ ALL (odds ratio (OR), 95% confidence interval (95% CI): 0.42, 0.22-0.81; p < 0.005) and HeH ALL (OR; 95% CI: 0.44, 0.30-0.65; p < 0.0001). These negative associations were almost entirely due to a single allele, DPB1*0101. Our results suggest that DPB1*0101 may afford protection from the development of TEL-AML1+ and HeH BCP ALL, possibly as the result of a DP-restricted immune response to BCP ALL-associated antigen(s), the identification of which could have important implications for the design of prophylactic vaccines.