The inhibitory effect on CALR-mutated cells was tested using chemical analogs of hematoxylin and MPN clinically used drugs. CALR WT, heterozygous mutant, and homozygous mutant cell lines were treated with indicated drugs for 72 hours. IC₅₀ was calculated by Graphpad Prism 7.0. Mutant IC₅₀ was calculated as the mean of heterozygous and homozygous mutant cells (n = 3).