Modulation of Plasma 25-Hydroxyvitamin D3 Level by Imatinib Mesylate in Patients with Chronic Myelogenous Leukemia: The Role of Uptake and Efflux Transporters.

Background: Vitamin D deficiency is a common side effect of imatinib mesylate (IM) therapy. Transporter polypeptides involved in the disposition of IM may be required for maintenance of adequate vitamin D concentrations. Objective: The aim of the present work is to study the association between the plasma concentrations of IM and plasma 25-hydroxyvitamin (25[OH]) D3 with transporter genotypes in patients with chronic myelogenous leukemia. Methods: A total of 77 adult patients with chronic myelogenous leukemia treated with IM participated in this study. Peak and trough plasma IM and 25(OH) vitamin D3 concentrations were measured and compared to the results of single nucleotide polymorphisms of the efflux transporting gene ABCB1-1236 C>T and the uptake transporting gene OATP1B3-334 T>G. Multiple linear regressions were used to examine the associations between 25(OH) vitamin D3 concentrations and a number of patient characteristics, including responses to therapy. Binary logistic regression analysis was used to predict odd ratios for the clinical response to IM. Results: Plasma 25(OH) vitamin D3 concentration quartile values were: 25%, 8.2 ng/mL; 50%, 9.8 ng/mL; and 75%, 12 ng/mL. High IM peak concentration, being OATP1B3-334 T>G (TT), and/ or ABCB1-1236 C>T (CT) are associated with lower concentrations of 25(OH) vitamin D3. Moreover, IM peak concentration, IM trough concentration, and plasma concentration of 25(OH) vitamin D3 were associated with the clinical response to IM. Conclusions: vitamin D, IM concentration, as well as the genotype of OATP1B3-334 T>G, had an influence on the response of patients with chronic myelogenous leukemia.

Determination of the Cut-off Value for Imatinib Plasma Levels Linked to Occurrence of Bone Pain in CML Patients.

Background: Imatinib is used to treat chronic myelogenous leukemia (CML). Variations in imatinib pharmacokinetics have been linked to genetic variations. That has an impact on imatinib response and adverse effects. Therefore, the aim of the study was to study bone pain as an adverse effect that occurs with imatinib and to investigate the risk factors for bone pain. Methods: The relationship between the peak and trough plasma concentrations of imatinib with bone pain as one of the most frequently occurring adverse effects was examined. Multiple linear regression analysis and binary logistic regression analysis were used to measure the impact of various patients' characteristics on both peak and trough imatinib concentrations and the risk of the occurrence of imatinib-induced bone pain. Results: As a side effect of imatinib, approximately 15% of patients with CML who were taking it experienced bone pain. This side effect was linked to the imatinib peak and trough plasma levels. Imatinib trough concentration was also linked to gender and the gene SLCO1B3-334T > G (TT). There were significant associations between peak concentrations and gender as well as patient weight. Conclusion: Higher peak and trough plasma concentrations of imatinib are linked with the risk of the occurrence of bone pain as a side effect of imatinib. Monitoring plasma concentrations of imatinib is useful to predict the bone pain of imatinib and to support quality of life in patients with CML.

Association of the Trough, Peak/Trough Ratio of Imatinib, Pyridine-N-Oxide Imatinib and ABCG2 SNPs 34 G>A and SLCO1B3 334 T>G With Imatinib Response in Egyptian Chronic Myeloid Leukemia Patients.

Imatinib mesylate (IM) is highly efficacious in the treatment of chronic myeloid leukemia (CML). Therapeutic drug monitoring and pharmacogenetic screening are affirmed for better management of IM therapy. The goal of this study was to gain a greater mechanistic understanding of the factors controlling variability in IM level and its relation to the response. One hundred and two patients with CML at chronic phase were recruited in this study. Blood samples were withdrawn at least 30 days after drug administration, and trough and peak concentrations of imatinib, N-des-methyl imatinib, and pyridine-N-oxide imatinib were determined by HPLC/MS/MS. Genetic polymorphism of the genes ABCG2 SNPs 34 G>A and 421C >A; ABCB1 SNPs 2677 G>A/T, 1236 C>T, 3435 C>T; SLCO1B3 SNPs 334 T>G and CYP3A5 were studied using PCR-RFLP technique. Our study presented significant higher trough IM (1,281 ± 578 ng/ml), lower Peak/Trough ratio, clearance (Cl), and elimination rate constant, ke, among patients who achieved favorable responses (N = 64) than those for patients who suffered unfavorable response (N = 37). The P/T ratio was the only significant independent factor affecting response, as the P/T ratio increased by one, the risk of unfavorable response increased by more than double as compared to favorable response with 95% CI (1.28-3.92, P = 00.005). Moreover, like the results of IM, the trough concentration of Pyridine-N-oxide imatinib was significantly higher (P = 0.01) and its P/T ratio was significantly lower (P = 0.008) in patients achieved favorable response than those without. The wild GG genotype of the ABCG2.34 G>A gene was associated with favorable response (P = 0.01), lower Cl, Ke and high plasma IM trough level than both (AA+GA) genotypes. ABCG2.421C >A (CC) genotype had a significantly higher plasma peak of IM, N-des-methyl imatinib and higher Css. The GG and TG alleles of the SLCO1B3.334 T>G gene were significantly correlated to favorable response, while the wild allele TT was linked to unfavorable response (P = 0.03). In conclusion, the trough and P/ T ratio for both IM and Pyridine-N-oxide imatinib, in addition to Polymorphism of ABCG2 SNPs 34 G>A and SLCO1B3.334 T>G gene, is a good predictor for response of IM in CML Egyptian patients.

N-Acetyltransferase 2 (NAT2) polymorphism as a risk modifier of susceptibility to pediatric acute lymphoblastic leukemia.

N-Acetyltransferases (NAT) have been known to modify the risk to a variety of solid tumors. However, the role of NAT2 polymorphism in risk susceptibility to childhood acute lymphoblastic leukemia (ALL) is still not well known. We performed a case-control study to determine if the common NAT2 polymorphisms play a role in altering susceptibility to pediatric ALL. DNA of 92 pediatric ALL patients and 312 healthy controls was analyzed for the NAT2 polymorphisms using the PCR-RFLP method. The wild-type NAT2*4 was encountered in 8.6 % of patients versus 11.8 % of controls (P = 0.23). The rapid acetylators NAT2*12 803A>G, AG, GG, and AG/GG were overrepresented in controls (P = 0.0001; odds ratio (OR) 0.22, 0.19, and 0.21 respectively). NAT2*5D 341T>C and NAT2*11A 481C>T were of comparable frequencies. For their combination, NAT2*5A, a slow acetylator, both TCTT and CCCT were overrepresented in patients (P < 0.001; OR 15.8 and 17.9 respectively). NAT2*5B (803A>G, 341T>C, 481C>T) was overrepresented in controls (P < 0.001; OR 0.12). Apparently, 803A>G ameliorated the combined effect of 341T>C and 481C>T. A similar effect was obtained with NAT2*5C (341T>A, 803A>G) (P < 0.0001; OR 0.11). For slow acetylator NAT2*7A 857G>A, GA and GA/AA were overrepresented in patients (P = 0.009 and 0.01; OR 2.74 and 2.72 respectively). NAT2*13 282C>T, NAT2*6B 590G>A, and NAT2*14A 191G>A were of comparable frequencies. NAT2 282C>A in combination with NAT2 857G>A (NAT2*7B) showed a synergistic effect in patients versus controls (P < 0.0001; OR 3.51). In conclusion, NAT2 gene polymorphism(s) with slow acetylator phenotype is generally associated with the risk of development of ALL in children.

Peripheral blood mammaglobin gene expression for diagnosis and prediction of metastasis in breast cancer patients.

AIM: To evaluate the value of peripheral blood mammaglobin (MG) gene expression for diagnosis and prediction of metastasis in breast cancer patients. METHODS: MG expression was detected by nested reverse-transcription polymerase chain reaction in the peripheral blood of 46 females (32 breast cancer, 12 benign breast lesions, 2 no breast abnormalities). In total 28 breast cancer patients were followed up through a period of 34 months for the development of metastasis. RESULTS: MG expression was detected in 16/32 (50%) breast cancer patients but not in patients with benign lesions or healthy participants. Five patients had metastasis at diagnosis. During the 34 months of follow up, five more MG-positive patients showed metastatic lesions and none of the MG negative patients who were followed up developed metastasis. CONCLUSION: The study suggests blood MG expression is a specific molecular marker for detection of occult mammary carcinoma cells of patients with operable breast cancer. It might be of value as a predictor of subsequent metastasis. Large-scale studies and longer follow-up periods are needed.

Synergistic effect of methyltetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphism as risk modifiers of pediatric acute lymphoblastic leukemia.

BACKGROUND AND PURPOSE: ALL is the most common pediatric cancer. The causes of the majority of pediatric acute leukemia are unknown and are likely to involve an interaction between genetic and environmental factors. Therefore, unfavourable gene-environmental interactions might be involved in the genesis of ALL. The aim of this work was to evaluate, in a case-control study, whether the common polymorphisms in 5, 10-methylenetetrahydrofolate reductase (MTHFR) namely (C677T and A1298C) and methionine synthase (MS) (A2756G) genes may play a role in altering susceptibility to pediatric ALL as individual genes and in combination. PATIENTS AND METHODS: DNA of 88 ALL patients (age < or = 18 years) and 311 healthy control subjects was analyzed for the polymorphisms of MTHFR and MS genes using PCR-RFLP method. RESULTS: The frequencies of the wild types of MTHFR 677CC, MTHFR 1298AA and MS 2756AA, the homozygous genotypes of MTHFR 677TT, MTHFR 1298CC and MS 2756GG and heterozygous genotypes of MTHFR 677CT and MS 2756AG showed no statistically significant differences between patients and controls. The frequency of the MTHFR 1298AC heterozygous genotype was 25% among patients compared to 45.0% among controls; the difference was found to be statistically significant (p value =0.001, O.R=0.382 & 95% C.I=0.222-0.658). The frequency of the MTHFR1298AC heterozygous genotype plus 1298CC homozygous genotype was 34% among patients compared to 54.3% among controls and the difference was statistically significant (p value =0.001). A synergistic effect of 677CT and1298AC (CTAC) was observed, (p value=0.002) with 3.65 fold protection (OR 0.273 & 95% C.I=0.155-0.9) compared to 2.6 folds for MTHFR 1298AC alone. This protective effect of CTAC polymorphism was abolished when combined with MS 2756AA or AG. CONCLUSION: The present study provided further evidence for the protective role of MTHFR 1298AC mutant alleles in acute lymphoblastic leukemia in children (2.6 fold protection). This suggests that folate and methionine metabolism play an important role in the pathogenesis of pediatric ALL. In contrast to the main bulk of literature, we did not find any protective role of either MTHFR C677T or MS A2756G polymorphisms. This may reflect the ethnic variation in both the polymorphism frequencies, variation in plasma level of folate, in addition to the possible role of gene-environment interaction mainly dietary availability of folate. The synergistic effect of MTHFR 1298AC and 677CT and its abolishment by MS 2756AA or AG further emphasizes that the interaction of genes, rather than the polymorphism in any single one, determines risk susceptibility to disease.

Comparative study of NMP-22, telomerase, and BTA in the detection of bladder cancer.

PURPOSE: The diagnostic efficacy of Nuclear Matrix Protein-22 (NMP-22), bladder tumor antigen (BTA TRAK), and telomerase activity was evaluated in urine in a trial to assess their value in the detection of bladder cancer and to compare it to that of routine urine cytology. SUBJECTS AND METHODS: The study included 46 newly diagnosed bladder cancer patients, diagnosed by cystoscopy and histopathological typing, in addition to 20 patients with benign bladder lesions and 20 healthy age and sex matched volunteers as a control group. Fifty percent of the cancer patients (23/46) had proven bilharzial history. Most patients (27/46) had transitional cell carcinoma (TCC), 17/46 had squamous cell carcinoma (SCC), while only 2 patients had adenocarcinoma. A single freshly voided urine sample (approximately 100ml) was collected from each patient and control subject and aliquoted for each test. All assays were conducted according to the manufacturer's guidelines and the results were compared to those of urine cytology. RESULTS: The optimal cutoffs for NMP-22, BTA and telomerase activity as calculated by ROC curves were 12.1 U/ml, 78 U/ml, 0.48 (Ratio) respectively. The levels of the three parameters were significantly higher in the malignant group compared to either the benign group or normal controls, (p<0.001) and the positive rates were also higher in the malignant group for all 3 parameters. The overall sensitivity of urine cytology, NMP-22, BTA and telomerase was 54.3%, 91.3%, 100% and 80.4% respectively. For bilharzial cancer bladder respective sensitivities were 69.6%, 95.6%, 100% and 73.9%, while for nonbilharzial cancer bladder the respective sensitivities were 39.1%, 87%, 100% and 87%. The overall specificities with urine cytology, NMP-22, BTA and telomerase was 100%, 87.5%, 92.5% and 95.0%, respectively. Combined sensitivity of voided urine cytology with one or more of the 3 biomarkers, or the use of these biomarkers in double or triple combinations gave higher positivity than each biomarker alone. CONCLUSION: BTA showed the highest sensitivity in all the studied parameters in the bladder cancer group, bilharzial bladder cancer subgroup, and non bilharzial bladder subgroup, (100%), while the highest specificity was recorded with urine cytology (100%), followed by telomerase (95%), then BTA (92.5%), and lastly NMP- 22 (87.5%). Use of markers in combination with cytology, or in a panel, improved the sensitivity, and specificity.