JAK2V617F mutation in chronic myeloid leukemia predicts early disease progression.

Objective: To determine the association of JAK2V617F mutation along with BCR-ABL translocation or Philadelphia chromosome in chronic myeloid leukemia with early disease progression to advanced stages (accelerated phase or blast crisis) and poor outcome.

Study Design: Case series.

Place And Duration Of Study: National Institute of Blood Diseases and Bone Marrow Transplantation, Karachi, from February 2008 to August 2009.

Methodology: All the newly diagnosed cases of BCR-ABL or Philadelphia positive CML were tested for JAK2V617F mutation by Nested PCR. Demographic data, spleen size, hemoglobin levels, white blood cell and platelet counts were recorded. Independent sample t-test was used for age, haemoglobin level and spleen size. Fisher's exact test was applied to compare disease progression in JAK2V617F mutation positive and negative cases.

Results: Out of 45 newly diagnosed cases of CML, 40 were in chronic phase, 01 in accelerated phase and 04 in blast crisis. JAK2V617F mutation was detected in 12 (26.7%) patients; 09 (22.5%) in chronic phase, none in accelerated phase and 03 (75%) in blast crisis. During a mean follow-up of 8 months, 03 patients in chronic phase transformed in blast crisis and 02 into accelerated phase. Overall 08 out 0f 11 (73%) JAK2V617F positive patients either had advanced disease or showed disease progression. Only 2 of 20 (10%) available patients, negative for the mutation, showed disease progression by transforming into blast crisis (p < 0.001). No statistically significant difference was seen in the age, spleen size, haemoglobin levels, white blood cells and platelets counts in JAK2V617F positive patients.

Conclusion: JAK2V617F mutation was detected in 26.7% cases of chronic myeloid leukemia. A significant proportion of them showed early disease progression.