JAK2V617F increases BaF3-Lu and HEL-Lu adhesion to laminin via LuS621. Cell adhesion to laminin was measured under flow conditions using (A) BaF3 JAK2 wt or BaF3 JAK2V617F and (B) HEL cells expressing Lu or the LuS621A mutant. Cells were incubated or not incubated with the JAK2 inhibitor HBCH. Histograms indicate the mean number ± SEM of adherent cells per mm² at each shear stress. Unpaired t test, (A) *P < .05, **P < .01, compared with BaF3 JAK2 wt Lu; ^#P < .05, ^##P < .01, ^###P < .001, compared with BaF3 JAK2V617F Lu; ^§§P < .01, ^§§§P < .001, compared with BaF3 JAK2V617F Lu; NS, nonsignificant, compared with BaF3 JAK2 wt Lu, (n = 6); (B) ***P < .001, compared with HEL-Lu (n = 3).