Predictive and Prognostic Implications of Variant Philadelphia Translocations in CML: Experience From a Tertiary Oncology Center in Southern India.
INTRODUCTION
Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by Philadelphia (Ph) chromosome with classical t(9;22)(q34;q11) seen in up to 90% of cases. However 5% to 10% of patients who present with variant Ph translocations (vPh) have been an area of research for their significance in predicting response to various therapies including tyrosine kinase inhibitors as well as prognosticating survival outcomes for many years involving varied patient populations, with conflicting results.


MATERIALS AND METHODS
We retrospectively analyzed our data from January 2002 to December 2014. Patients with vPh in chronic phase of CML (CML-CP) were analyzed with respect to their demographic parameters, response to imatinib therapy, and survival and their data were compared with data of patients with classical Ph translocation (cPh).


RESULTS
Of 615 patients diagnosed with CML-CP, 72 patients (11.7%) showed vPh. Most common chromosomes involved in these translocations were 14 (13.9%), 11 (12.5%), 19 (9.7%), and 7 (8.3%). Rates of complete hematological response, complete cytogenetic response, and major molecular response were not statistically different between the groups. At 5 years, event-free survival, failure-free survival, progression-free survival, and overall survival were 60% versus 67.9%, 62.7% versus 69.7%, 84.7% versus 92.1%, and 87.5% versus 92.4%, respectively, in vPh and cPh. The differences in survival were statistically not significant.


CONCLUSION
To our knowledge, this is the largest series of variant translocations in CML-CP, pertaining to the Indian population. Our data suggest that the presence of vPh in CML has no significant effect in predicting response to imatinib as well as in prognosticating survival.
['Kanakasetty|Govind Babu|GB|', 'Kuntejowdahalli|Lakshmaiah|L|', 'Thanky|Aditi Harsh|AH|', 'Dasappa|Lokanatha|L|', 'Jacob|Linu Abraham|LA|', 'Mallekavu|Suresh Babu|SB|', 'Kumari|Prasanna|P|']
D000293:Adolescent D000328:Adult D000368:Aged D000970:Antineoplastic Agents D018572:Disease-Free Survival D005260:Female D006801:Humans D000068877:Imatinib Mesylate D007194:India D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive D008297:Male D008875:Middle Aged D010677:Philadelphia Chromosome D011379:Prognosis D047428:Protein Kinase Inhibitors D012189:Retrospective Studies D014178:Translocation, Genetic D055815:Young Adult
Chronic myeloid leukemia Imatinib Variant translocation Indian population Prognostic and predictive markers