The impact of CYP2D6*4 and GSTP1 Ile105Val polymorphisms on the susceptibility to develop BCR-ABL1 negative myeloproliferative neoplasms.

Inter-individual variations in the genes encoding xenobiotic-metabolizing enzymes have been reported to alter susceptibility to various diseases involving hematological disorders. The purpose of this case-control study was to investigate the relationship between CYP2D6*4 and GSTP1 Ile105Val polymorphisms and the risk of developing BCR-ABL1 negative myeloproliferative neoplasms (MPN). PCR-RFLP was used for genotyping single nucleotide polymorphisms (SNP) in CYP2D6 and GSTP1 in 139 patients with MPN and 126 controls. There was a significantly increased risk for developing BCR-ABL1 negative MPN for the group bearing the CYP2D6*4 variant allele (X2: 4.487; OR 1.738; 95% CI 1.040-2.904; p = 0.034). The platelet count was higher in CYP2D6*4 allele carriers (p = 0.047). There was no association between the GSTP1 Ile105Val polymorphism and the risk of developing MPNs. MPN patients bearing the GSTP1 Ile105Val variant allele had a higher prevalence of bleeding complications (X2: 7.510; OR 4.635; 95% CI 1.466-14.650; p = 0.006). Our study provides new data that the CYP2D6*4 polymorphism may be associated with an increased risk to develop MPNs while the GSTP1 Ile105Val polymorphism does not show such an association. To our knowledge, the current study is the first to investigate the relationship between CYP2D6*4 and GSTP1 Ile105Val polymorphisms and the risk of developing MPNs in the Turkish population. Further studies with more patients and controls are needed to support our data.

Impact of JAK2V617F Mutational Status on Phenotypic Features in Essential Thrombocythemia and Primary Myelofibrosis.

OBJECTIVE: The JAK2V617F mutation is present in the majority of patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). The impact of this mutation on disease phenotype in ET and PMF is still a matter of discussion. This study aims to determine whether there are differences in clinical presentation and disease outcome between ET and PMF patients with and without the JAK2V617F mutation. MATERIALS AND METHODS: In this single-center study, a total of 184 consecutive Philadelphia-negative chronic myeloproliferative neoplasms, 107 cases of ET and 77 cases of PMF, were genotyped for JAK2V617F mutation using the JAK2 Ipsogen MutaScreen assay, which involves allele-specific polymerase chain reaction. RESULTS: ET patients positive for JAK2V617F mutation had higher hemoglobin (Hb) and hematocrit (Hct) levels, lower platelet counts, and more prevalent splenomegaly at diagnosis compared to patients negative for the JAK2V617F mutation, but rates of major thrombotic events, arterial thrombosis, and venous thrombosis were comparable between the groups. At presentation, PMF patients with JAK2V617F mutation had significantly higher Hb and Hct levels and leukocyte counts than patients without the mutation. Similar to the findings of ET patients, thromboembolic rates were similar in PMF patients with and without theJAK2V617F mutation. For ET and PMF patients, no difference was observed in rates of death with respect to JAK2V617F mutational status. Moreover, leukemic transformation rate was not different in our PMF patients with and without JAK2V617F mutation. CONCLUSION: We conclude that JAK2V617F-mutated ET patients express a polycythemia vera-like phenotype and JAK2V617F mutation in PMF patients is associated with a more pronounced myeloproliferative phenotype.

The Clinical Significance of IDH Mutations in Essential Thrombocythemia and Primary Myelofibrosis.

BACKGROUND: Limited data exist regarding impact of IDH mutations in Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs). Prognostic significance of IDH mutations was asessed in 184 Ph-negative MPN patients - 107 essential thrombocythemia (ET) and 77 primary myelofibrosis (PMF). METHODS: High-resolution melting (HRM) analysis was used to detect IDH1 and IDH2 mutations. RESULTS: PMF and ET patients showed no significant difference for prevalence of IDH mutations. Mutant IDH (IDH1 or IDH2) was documented in five of PMF (6.5%) and two of ET patients (1.9%). IDH mutations in ET patients included one IDH1 R132C and one IDH2 R140Q. Of the five IDH-mutated PMF patients, four (80%) displayed IDH1 (three IDH1 R132C and one IDH1 R132S) and one (20%) carried IDH2 (IDH2 R140Q) mutation. Sixty percent (three in five) of IDH-mutated PMF patients carried JAK2V617F with following allele burdens: 31-50%, 5-12.5% and 31-50%, respectively. Three of 77 PMF patients (3.9%) simultaneously harbored IDH and JAK2V617F mutations. IDH mutations in PMF showed a trend towards higher rate in females (100% and 52.8%, respectively). Bleeding complications were significantly higher in IDH-mutated PMF patients compared to IDH wild-type counterparts. Trend towards a lower prevalance of acetylsalicylic acid (ASA) use was present in IDH mutant PMF patients compared to wild-type counterparts (20% and 63.9%, respectively). Death rate was higher in IDH-mutated PMF patients compared to IDH wild-type PMF patients (60% and 15.3%). In univariate analysis, a significantly shorter leukemia-free survival (LFS) was observed in IDH-mutated PMF patients. CONCLUSIONS: We conclude that IDH mutations indicate a risk for leukemic transformation in PMF.

Prognostic significance of ASXL1, JAK2V617F mutations and JAK2V617F allele burden in Philadelphia-negative myeloproliferative neoplasms.

BACKGROUND: Despite insights into the genetic basis of Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs), a significant proportion of essential thrombocythemia (ET) and primary myelofibrosis (PMF) patients present with no known MPN disease alleles. There were no previous studies investigating the impact of ASXL1 mutations in Ph-negative MPNs in Turkey. In the current study, we investigated the prognostic significance of ASXL1 mutations in Turkish MPN patients. We also aimed to determine the prognostic significance of JAK2V617F allele burden and the relationship of JAK2V617F mutation with ASXL1 mutations in Ph-negative MPNs. METHODS: About 184 patients from a single center diagnosed with Ph-negative MPNs were screened for ASXL1, JAK2V617F mutations, and JAK2V617F allele burden: 107 ET and 77 PMF. RESULTS: A total of 29 ASXL1 mutations were detected in 24.7% of PMF and 8.4% of ET patients. ASXL1-mutated ET patients showed a trend toward an increase in the incidence of cerebrovascular events and higher total leukocyte counts. ASXL1-mutation in PMF was associated with older age and a higher prevalence of bleeding complications. In univariate analysis, overall survival (OS) was significantly reduced in ASXL1-mutated PMF patients. In multivariate analysis, Dynamic International Prognostic Scoring System-plus high-risk category and ASXL1 mutation status were independently associated with shorter survival in PMF. In PMF, mutational status and allele burden of JAK2V617F showed no difference in terms of OS and leukemia-free survival. CONCLUSION: We conclude that ASXL1 mutations are molecular predictors of short OS in PMF.

The Burden of JAK2V617F Mutated Allele in Turkish Patients With Myeloproliferative Neoplasms.

BACKGROUND: Studies regarding the impact of JAK2V617F allele burden on phenotypic properties and clinical course in Philadelphia-negative myeloproliferative neoplasms (Ph-negative MPNs) have reported variable results. We aimed to analyze the association of mutated JAK2V617F allele burden with laboratory characteristics and clinical phenotype in Turkish patients (107 essential thrombocythemia (ET) and 77 primary myelofibrosis (PMF)). METHODS: Peripheral blood samples of 184 patients with Ph-negative MPNs were analyzed for JAK2V617F allele status and burden. JAK2 MutaScreen assay (Ipsogen, Luminy Biotech, Marseille, France) was used to detect the JAK2V617F status and quantitative JAK2V617F allele burdens in genomic DNA using TaqMan allelic discrimination. RESULTS: Frequency of JAK2V617F-positive patients with high mutation load (allele burden > 50%) was higher in PMF compared to ET (23.4% and 4.7%, respectively; P = 0.001). We found significant association between ET patients with high JAK2V617F allele burden and lower hemoglobin (Hgb) and hematocrit (Hct), higher LDH levels and more prevalent massive splenomegaly (P = 0.001, P = 0.001, P = 0.012 and P = 0.015, respectively). ET patients with high mutation load displayed higher prevalence of bleeding compared to low mutation load and wild-type mutational status (P = 0.003). Rate of DVT was significantly higher in ET patients with mutant allele burden in upper half compared to lower half and wild-type (P = 0.029). We observed significant association between PMF patients with high JAK2V617F allele burden and higher Hgb, Hct levels and leukocyte counts (P = 0.003, P = 0.021 and P = 0.001, respectively). CONCLUSIONS: Our study demonstrated JAK2V617F allele burden correlates with clinical features in ET and PMF. We conclude quantification of JAK2V617F mutation contributes to the workup of Ph-negative MPNs.

Investigation of BRAF V600E mutation in papillary thyroid carcinoma and tumor-surrounding nontumoral tissues.

The aim of this study was to investigate the association between the BRAF V600E mutation incidence and histopathologic prognostic risk factors for papillary thyroid carcinoma (PTC) on the Turkish population. The contribution of BRAF V600E mutation in both tumor and tumor-surrounding nontumoral tissues of 108 patients with PTC was assessed using mutant allele-specific amplification-polymerase chain reaction. The BRAF V600E mutation was found in 52.8% of the tumor tissues, and 7.4% of the tumor-surrounding nontumoral tissues. The BRAF V600E mutation was significantly higher in the tumor tissues of the classic variant of PTC (CVPTC) cases than the follicular variant of PTC cases (p=0.001). The presence of the BRAF V600E mutation was more frequent in women, but this gender difference was not statistically significant. BRAF V600E mutation was more frequent in patients with either one of adenomatous hyperplasia or diffuse hyperplasia in tumor-surrounding nontumoral tissues (p=0.012). There was no significant difference in the BRAF V600E mutation distribution among tumor-surrounding nontumoral tissues of the two PTC variants, but it was more frequent in the CVPTC. Recent data suggest that BRAF V600E is an important marker, especially, for CVPTC. We propose that patients who had subtotal thyroid resection might have an increased risk of recurrence at the residual thyroid tissue if they have BRAF V600E mutation in their tumor-surrounding nontumoral tissues.