METHODOLOGY: Representative paraffin blocks of synovial sarcoma were utilized in this study. FISH study was performed on formalin-fixed paraffin embedded tissue sections using the SYT-SSX break apart probe from Cytocell, to detect two form of SYT-SSX transcript, SYT-SSX1 and SYT-SSX2. FISH protocol, including the hybridization was done following two different protocols, Cytocell FISH protocol and Optimized Dako FISH protocol.
RESULTS: Tissue samples subjected to FISH using Cytocell FISH protocol showed the absence of signal corresponding to the probe used. Utilizing Optimized Dako FISH protocol, the two signals (red and green) corresponding to the break-apart probes was detected. These findings suggested that Optimised Dako FISH protocol is more suited for use with the tested probe on paraffin embedded tissues in comparison to Cytocell FISH protocol.
CONCLUSION: Optimised Dako FISH protocol was noted to be more suited for detecting SYT-SSX FISH signals on paraffin embedded tissues in comparison to Cytocell FISH protocol.
MATERIALS AND METHODS: Peripheral blood samples was collected from 63 AML patients to study their morphological, cytogenetic and molecular features. PCR was used to determine the prevalence of FLT3 mutations; internal tandem duplication (ITD) and tyrosine kinase domain (TKD) in AML patients.
RESULTS: Among 63 AML patients, 42 were males and 21 were females with male to female ratio 2:1 with median age of 32 years. AML-M2 was the predominant French-American-British (FAB) subtype (42%) followed by M4 (27%), M3 (8%), M1 (8%), M0 (8%) and M5 (7%) respectively. Cytogenetic analysis of 60 patients showed 58% as cytogenetically normal (CN) whereas 42% had aberrant karyotype.The most frequent aberrations were trisomy8, t(8;21), t(15;17) (8.3%) each, inversion16 (5%), and different deletions (12%) respectively. FAB-M4 subtype showed most of the chromosomal anomalies. Among 63 AML patients, 22% showed FLT3/ITD while 6.4% had D835 mutation after molecular analysis. FLT3 mutations were found in most of the FAB subtypes and cytogenetic groups. FLT3/ITD mutations were more common in patients with normal karyotype (26%) and usually present with hyperleukocytosis but association between two was not significant.
CONCLUSION: The cytogenetic data of adult AML from Pakistan showed presence of favourable prognostic karyotype with comparable prevalence as reported in international data. Moreover, FLT3/ITD mutations are commonly found in our patients as determined by molecular analysis. Therefore, inclusion of this unfavourable prognostic marker should be routine in molecular diagnostic testing of AML.
CASE: A 60-year-old woman presented with abdominal discomfort and hyperleukocytosis. She was diagnosed as CML in the chronic phase with positive BCR-ABL1 transcripts. Due to the failure to obtain an optimal response with imatinib treatment, it was switched to nilotinib. She responded well to nilotinib initially and achieved complete haematological and cytogenetic responses, with undetectable BCR-ABL1 transcripts. However, in 4 years she developed molecular relapse. Mutation analysis which was done 70 months after commencement of nilotinib showed the presence of BCRABL1 kinase domain mutation with nucleotide substitution at position 1187 from Histidine(H) to Proline(P) (H396P). Currently, she is on nilotinib 400mg twice daily. Her latest molecular analysis showed the presence of residual BCR-ABL1 transcripts at 0.22%.
DISCUSSION/CONCLUSION: This case illustrates the importance of BCR-ABL1 mutation analysis in CML patients with persistent BCR-ABL1 positivity in spite of treatment. Early detection and identification of the type of BCRABL1 mutation are important to guide appropriate treatment options as different mutation will have different sensitivity to TKI.