ABSTRACT
Chronic Myeloid Leukemia, BCR-ABL1 positive (CML) is distinct from other myeloproliferative neoplasms (MPNs) as it is positive for the Philadelphia chromosome (Ph) with presence of BCR-ABL1 translocation that makes it responsive to targeted therapy with tyrosine kinase inhibitors (TKI). Distinctly there is another group of Ph-negative myeloproliferative neoplasms as polycythemia vera (PV), primary myelofibrosis (PMF), essential thrombocythemia (ET) and others that harbor an activating mutation in the Janus Kinase 2 gene (JAK2), i.e., JAK2 V617F mutation. BCR-ABL1 translocation and the JAK2 V617F mutation are generally considered disease defining and mutually exclusive due to diagnostic and therapeutic implications. We hereby present a rare case of MPN with coexistent expression of BCR-ABL1 translocation and JAK2 V617F mutation thus posing a challenge in diagnosis, treatment, and follow-up.
Subject(s)
Fusion Proteins, bcr-abl/genetics , Janus Kinase 2/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/pathology , Primary Myelofibrosis/genetics , Dasatinib/therapeutic use , Female , Humans , Hydroxyurea/therapeutic use , In Situ Hybridization, Fluorescence , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/diagnosis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Middle Aged , Philadelphia Chromosome , Primary Myelofibrosis/diagnosis , Primary Myelofibrosis/pathologyABSTRACT
Genetic variants influencing the pharmacokinetics and/or pharmacodynamics of the chemotherapeutic drugs used in Acute Lymphoblastic Leukemia (ALL) therapy often contribute to the occurrence of treatment related toxicity (TRT). In this study, we explored the association of candidate genetic variants with early hematological TRT (grade 3-4) occurring within the first 100 days of low-dose methotrexate and 6-mercaptopurine based maintenance therapy (n = 73). Fourteen variants in the following candidate genes were genotyped using allele discrimination assay by real-time PCR: ABCB1, DHFR, GGH, FPGS, MTHFR, RFC1, SLCO1B1, TPMT, and NUDT15. Methotrexate polyglutamate (MTXPG3-5) levels in red blood cells were measured by LC-MS/MS. Early hematological TRT (grade 3-4) was seen in 54.9% of patients. The NUDT15*3 allele was associated with early TRT occurrence [HR: 3.04 (95% CI: 1.5-6.1); p = 0.007]. Sensitivity of early TRT prediction improved (from 30.7% to 89.7%) by considering FPGS variant (rs1544105) carrier status along with NUDT15*3 allele [HR = 2.7 (1.5-4.7, p = 0.008)]. None of the considered genetic variants were associated with MTXPG3-5 levels, which in turn were not associated with early TRT. NUDT15*3 allele carrier status could be used as a stratifying marker for Indian ALL patients to distinguish patients at high or low risk of developing early hematological TRT.