Sensitive and reliable detection of KIT p.D816V mutation in decalcified archival bone marrow trephines

The majority of mastocytosis cases are characterized by an activating mutation in the KIT gene in codon 816. The detection of this alteration is of importance for proper diagnostic workup. Therefore, reliable and sensitive methods for the detection of KIT Codon 816 hotspot mutations in various types of patient samples are required. Since mutated cancer genes are often overexpressed, we evaluated the feasibility and sensitivity of KIT p.D816V detection by analysing mRNA/cDNA instead of genomic DNA. From 80 bone marrow trephines harboring a KIT p.D816 mutation, seven were only mutated by mRNA/cDNA pyrosequencing and 11 only by digital PCR analysis of genomic DNA. These results clearly demonstrate that detection of clinically relevant mutations in mRNA extracted from routinely processed decalcified archival bone marrow trephines is not only possible in a reliable fashion but under many circumstances advantageous. This enables the direct correlation of genomic data with high-quality morphological evaluation.