“…To examine the localization of endogenous FLT3, we performed confocal immunofluorescence microscopic analyses on human leukemia cell lines with an anti-FLT3 luminal-faced N-terminal region antibody. For immunostaining, we chemically fixed and permeabilized THP-1 (acute monocytic leukemia, FLT3 WT/WT ), RS4-11 (AML, FLT3 WT/WT ), MV4-11 (AML, FLT3 ITD/ITD ), MOLM-14 (AML, FLT3 WT/ITD ), and Kasumi-6 (AML, FLT3 ITD/ITD ) (Quentmeier et al, 2003;Furukawa et al, 2007;Wang et al, 2018;van Alphen et al, 2020; Figure 1A). In FLT3-wt leukemia cell lines (THP-1 and RS4-11), the wild-type receptor was mainly found at the PM ( Figure 1B, upper panels).…”