Plasma PDGF is positively correlated with VEGF levels in patients with progressive disease requiring therapy, late Rai stage, ZAP-70, and CD38 positive CLL patients. (A-D) In CLL patients with progressive disease requiring therapy (r = 0.82, P = .003), Rai stage II-IV (r = 0.88, P < .001), CD38 positive patients (r = 0.81, P = .02), and ZAP-70 positive patients (r = 0.52, P = .06), plasma PDGF strongly associated with VEGF levels. Linear regression analysis of PDGF versus VEGF levels was represented by the line in each dot plot.