Bivariate correlations reveal relationships between Stat pathway parameters. (A) In unstimulated cells, pY-Stat3 and pY-Stat5 levels were weakly related. (B) Basal pY-Stat3 was positively correlated with the total amount of Stat3 available. (C) The levels of pY-Stat3 and pY-Stat5 were tightly correlated in G-CSF–stimulated cells. (D) The levels of G-CSF–induced pY-Stat3 and IL-6–induced pY-Stat3 were positively correlated, as well. Lines at log₂(ΔMFI) of 1 indicate the threshold for considering a sample “responsive” at these doses. (E) The magnitude of the pY-Stat3 response to G-CSF was significantly correlated with the level of G-CSFR expression. (F) The magnitude of the pY-Stat3 response to IL-6 + sIL-6R was inversely correlated with gp130 expression. G-CSF stimulation: 100 ng/mL; IL-6 + sIL-6R stimulation: 50 + 100 ng/mL. R = Spearman correlation coefficient.