Cytogenetic and Molecular Analyses of Philadelphia Chromosome Variants in CML (chronic myeloid leukemia) Patients from Sindh using Karyotyping and RT-PCR

OBJECTIVE To determine the frequency of Philadelphia chromosome (Ph) and its variants in chronic myeloid leukemia (CML) cases at a tertiary care hospital of Sindh. METHODS The study was conducted at the Department of Pathology, Liaquat University of Medical and Health Sciences, Jamshoro and Isra University Hospital, Hyderabad during May-to-September 2014. Bone marrow and peripheral blood samples from a total of 145 diagnosed cases of CML were collected. Cytogenetic analyses were performed using karyotyping as per the International System for Human Cytogenetic Nomenclature guidelines. All karyotypic images were analyzed using the Cytovision software. In order to identify BCR-ABL transcripts, RT-PCR was performed. Statistical analysis of the data was done using SPSS-version-21.0. RESULTS Of the 145 samples, a total of 133 (91.7%) were positive for the Ph (Ph+) while 12 (8.3%) were negative for the Ph (Ph-). Of the 133 Ph+ samples, standard karyotypes were noted in 121 (91%), simple variants in 9 (6.7%) and complex variants in 3 (2.3%) of the samples. All the Ph+ samples (n=133) showed BCR-ABL positivity. Of the 12 Ph- samples, a total of 7 (58.3%) were BCR-ABL-positive and 5 (41.6%) were BCR-ABL-negative. CONCLUSION Frequency of the Ph was found to be of 90.9% in CML patients using a highly sensitive technique, the RT-PCR. Cytogenetic abnormalities were at a lower frequency. Cytogenetic and molecular studies must be conducted for better management of CML cases. These findings could be very useful in guiding the appropriate therapeutic options for CML patients.