The role of ß-catenin and paired-like homeobox 2B (PHOX2B) expression in neuroblastoma patients; predictive and prognostic value.

BACKGROUND: The expression of ß-catenin and paired-like homeobox 2B (PHOX2B) expression were assessed in Neuroblastoma (NB) patients as a diagnostic, prognostic and/or predictive markers. METHODS: Bone marrow (BM) samples of 52 NB patients were assessed for the expression of ß-catenin by immunohistochemistry (IHC), and PHOX2B by real time PCR (RT-PCR), compared to 12 healthy normal controls (NC). The data were correlated to the clinic-pathological features of the patients, response to treatment and disease relapse. RESULTS: ß-catenin was expressed in 40 (76.92%) patients (P < .001). While PHOX2B was expressed in 32/52 (61.5%) patients, with a fold change of 0.29 (0.01-40.0, P = .096). ß-catenin expression associated significantly with advanced tumor stage, high risk, positive results by MIBG and bone scan (P = .002, P < .001, P = .006, P = .013; respectively). Also it associated significantly with synaptophysin expression in the BM biopsy (P < .001), with a significant concordance (K = 0.519, P < .001). The expression of ß-catenin associated significantly with PHOX2B gene expression [28/32 (87.5%), P = .04], and its fold change (P = .027), with a significant measure of agreement (K = 0.297, P = .022). The fold change of PHOX2B gene expression associated significantly with the high risk of the patients (P = .04). Poor response to treatment associated significantly with the expression of neuron specific enolase (NSE), ß-catenin and PHOX2B in NB patients (P = .021, P = .019 and P = .040; respectively). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of synaptophysin for the diagnosis of BM metastasis in NB patients were (69%, 65.2%, 71.4%, 62.5%; respectively, P = .024). While with ß-catenin (93.1%, 43.5%, 67.5%, 83.3%; respectively, P = .003), and PHOX2B expression (65.5%, 34.5%, 59.4%, 50%; respectively, P = .574). CONCLUSION: ß-Catenin could be used as a sensitive and reliable marker for detection of BM metastasis and also a good predictor for resistance to treatment in NB patients. While, PHOX2B gene expression in BM aspirate could be a marker for high risk patients and poor response to treatment.

Study of the pharmacokinetic and pharmacogenetic contribution to the toxicity of high-dose methotrexate in children with acute lymphoblastic leukemia.

Methotrexate inhibits the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate by methylenetetrahydrofolate reductase (MTHFR). MTHFR has a common functional polymorphism C677T. The present study aimed to investigate the prevalence of MTHFR polymorphisms in Egyptian children with ALL and the relation to MTX-related toxicity, relapse, and MTX pharmacokinetic parameters. Forty patients with ALL were included in the study. They were treated according to ALL-NCI total XIII protocol. MTX-related toxicity and MTX pharmacokinetic parameters were assessed during therapy. MTHFR genotyping was done with a PCR-based restriction fragment length polymorphism assay, and MTX pharmacokinetic parameters were assessed by HPLC. The MTHFR C677T polymeric allele frequencies were 55, 35, and 10% for CC, CT, and TT genotypes, respectively, among the studied patients with ALL. MTX therapy was significantly associated with toxicity signs in TT genotype: elevated transaminases (P < 0.0001), elevated serum alpha 1-microglobulin protein (P < 0.0001), anemia (P < 0.0001), neutropenia (P < 0.0001), thrombocytopenia (P < 0.0001), and elevated CSF-ß-glucuronidase activity (P < 0.0001). Patients with TT genotype showed significant increase in MTX t(½) and AUC (P < 0.0001), while MTX elimination rate and total body clearance were significantly decreased (P < 0.0001 and P < 0.05, respectively) compared with CC genotype. The TT genotype was significantly associated with relapse in 2 years in 50% compared with 28.57% in CT and 13.64% in CC alleles. The overall 2-year survival was significantly lower in TT genotype (50%) compared with CC genotype (90.91%; P = 0.01). MTHFR TT genotype is significantly associated with increased toxicity during methotrexate therapy as well as increased relapse rate in pediatric patients with ALL. In future, MTX dose adjustment in ALL treatment protocols should be considered based on patient's genotype.

Detection of anti-asparaginase antibodies during therapy with E.coli asparaginase in children with newly diagnosed acute lymphoblastic leukemia and lymphoma.

BACKGROUND: Asparaginase is an effective antileukemic agent which is included in most front-line protocols for pediatric acute lymphoblastic leukemia (ALL) worldwide. Since asparaginase is a bacterial protein, it may induce formation of antibodies. The reported frequency of anti-asparaginase antibodies is highly variable: antibodies have been reported in as many as 79% of adults and as many as 70% of children after intravenous or intramuscular administration of E.coli asparaginase. PURPOSE: The aim of this study was to determine if the presence of antibodies during induction and continuation phases in newly diagnosed children with ALL and lymphoblastic lymphoma during therapy with E.coli asparaginase, had any correlation with various factors such as: age, gender, hypersensitivity reactions, response to therapy and Event Free Survival (EFS). PATIENTS AND METHODS: Between the period from March 2005 to May 2007, sixty-four children who attended the Menia outpatient pediatric oncology clinic, or were admitted to the inpatient department of the Menia oncology center, were enrolled in the study. Forty children had newly diagnosed ALL and 24 had lymphoblastic lymphoma. Patients were 48 males (75%) and 16 females (25%) with a male:female ratio 3:1. Their ages ranged from 3.5 to 17 years with mean age of 9.6 years. All patients received asparaginase therapy according to the St. Jude Total XIII protocol, in a dose of 10,000 IU/m(2)/dose, intramuscularly for 6-9 doses during the induction phase and another 6-9 doses during continuation phase according to disease status. RESULTS: Forty one patients achieved complete remission, 9 had partial remission, and 14 were lost to followup at different intervals of treatment. Antiasparaginase antibodies were detected in 36 patients (56%) out of 64 patients, and 37 patients (60%) out of 62 patients who were treated with asparaginase at day 8 and day 27 of induction phase respectively. Moreover, 33 patients (61%) out of 54 patients, and 41 patients (83%) out of 50 patients had positive antiasparaginase antibodies at week 10 and week 21 of continuation phase respectively. The 2-year EFS of the whole group was 50%. There was no statistically significant relation between positivity of antiasparaginase antibodies and the following: age, gender, hypersensitivity reaction, response to therapy and EFS. CONCLUSIONS: The presence of antiasparaginase antibodies was unrelated to age, gender, hypersensitivity reaction, response to therapy and event free survival of newly diagnosed children with acute lymphoblastic leukemia and lymphoblastic lymphoma.