A number of other CLL factors might have pro-angiogenic activity: fibroblast growth factor-2, certain chemokines (such as CXCL-12 and CXCL-2), tumor necrosis factor-α, insulin-like growth factor-1, neutrophil gelatinase-associated lipocalin, and progranulin. Here, IGF1 is linked to B-cell chronic lymphocytic leukemia.