Incidence and prognosis of c-KIT and FLT3 mutations in core binding factor (CBF) acute myeloid leukaemias.

DNA from 110 adult de novo acute myeloid leukaemia (AML) patients exhibiting either inv(16) (n = 63) or t(8;21) (n = 47) was screened for mutations in the c-KIT (exon 8 and Asp816) and FLT3 (ITD and Asp835) genes. c-KIT exon 8 mutations were found in 15/63 (23.8%) inv(16) patients and 1/47 (2.1%) t(8;21) patients. c-KIT Asp816 mutations were present in 5/63 (7.9%) inv(16) AML and 5/47 (10.6%) t(8;21) AML. FLT3 mutations were identified in five patients (7.9%) with inv(16) and three patients (5.6%) with t(8;21) AML. All mutations were mutually exclusive; 40% of inv(16) AML patients possessed either a c-KIT or FLT3 mutation. c-KIT exon 8 mutations were shown to be a significant factor adversely affecting relapse rate.

Mutational analysis of class III receptor tyrosine kinases (C-KIT, C-FMS, FLT3) in idiopathic myelofibrosis.

Genomic DNA from patients with idiopathic myelofibrosis (IMF) was screened by polymerase chain reaction (PCR) and conformation sensitive gel electrophoresis (CSGE) for mutations in the C-KIT gene (60 patients), as well as the C-FMS and FLT3 genes (40 patients). Intronic primers were used to amplify the entire coding region of both the C-KIT and C-FMS genes, and selected regions of the FLT3 gene. CSGE and direct DNA sequencing detected all previously reported as well as several novel polymorphisms in each of the genes. A novel c-fms exon 9 mutation (Gly413Ser) was detected in two patients. Its functional significance remains to be determined. The c-kit mutation Asp52Asn, previously described in two of six IMF patients in Japan, was not detected in this study. In addition, the reported c-fms mutations involving codons 301 and 969 were not identified. Therefore, in contrast to acute myeloid leukaemia, mutations in RTKs class III do not appear to play a significant pathogenetic role in idiopathic myelofibrosis.