RESUMO
The IRF-1 protein, a mammalian transcriptional factor encoded by a gene located in 5q23-q31, has antioncogenic properties. Involved in regulation of differentiation and proliferation, IRF-1 acts as a tumor suppressor gene and is inactivated by deletion of its one or more exons (exon skipping) in many hematological malignancies, including acute myelocytic leukemia (AML) and myelodysplastic syndromes (MDS). DNA samples, extracted from peripheral blood, taken from 50 Kashmiri AML subjects, were analysed using the polymerase chain reaction and compared with examples of age and gender matched healthy controls from the same population. Three different exon regions (2, 3 and 4) of the IRF-1 gene that were previously shown to be prone to deletion were selected for amplification and analysis. Deletion was observed in 31(62%) out of 50 AML patients (p=0.016). Exon 3 was most frequently deleted (58%), followed by exon 2 (28%), while exon 4 was least affected (12%), providing insights into critical roles in leukemogenesis. The number of deleted exons was variable, but single exon deletions were more frequent (30%). Of interest, IRF-1 gene deletions were not observed in 19 (38%) patients. In our study, the frequency of deletions of these three exons was slightly higher than in an Indian population (52%), but lower than in Sweden in Europe (95%). This study also explored the prevalence and clinical profile of IRF-1 deletions in AML patients. Adults had a significantly higher incidence than children (p=0.0168) and IRF-1 deletions were associated with low Hb (p< 0.0001), high TLC (p=0.0033) and a low platelet count (p=0.0076).
