Comparison of DNA Sequencing and Multispecific Monoclonal Antibody (Msmab-1) based Immunohistochemical Detection of IDH1/2 Mutation in Acute Myeloid Leukemia Cases.

Background: The IDH1/2 mutation is an important epigenetic modifier involved in the pathogenesis of AML. It is associated with variable prognosis in AML cases. Lack of proper molecular diagnostic infrastructure and high cost limits the routine use of PCR with sequencing as routine diagnostic methodology. The aim of this study was to find the prevalence of IDH mutation in AML cases using both PCR with sequencing and Immunohistochemistry method. Methods: We evaluated 60 patients registered at KGMU, Lucknow for diagnosis and treatment of AML. PCR followed by sequencing was done. IHC staining of the IDH1/2 mutation was performed on all cases using bone biopsy or clot section (in cases of pediatric AML cases). Results: Out of the total 60 patients of AML 4(6.7%) patients had IDH1R312 mutation and 5(8.3%) Patients had IDH2R172 mutation. IDH2 R140 mutation was not detected in any sample. On immunohistochemistry analysis 10 cases showed positive staining against anti IDH1/2 mutant (R132/R172) antibody, clone MsMab-1 with a sensitivity of 77.8% and specificity of 94.1%. Conclusion: IHC could be an alternative method to direct Sanger sequencing for IDH1/2 mutation detection in AML cases. However, the antibody used in the study is not effective for individual assessment of IDH1 and IDH2 mutation. Keywords: Immunohistochemistry, Sanger sequencing, IDH1/2 Mutation, Acute Myeloid Leukemia