Angiogenesis related genes up-regulated by CH-PH only in the presence of SU5416 include multiple pro-angiogenic inflammatory mediators (IL-1β, IL-6, TNFα) that may suggest an alternative pathway(s) promoting microvascular remodeling in the presence of VEGFR-2 tyrosine kinase blockade. The gene discussed is IL1B; the disease is cyclic hematopoiesis.