IFNA1 and hairy cell leukemia: However, when employed in the treatment of this form of cancer, IFN-α is used in conjunction with other forms of biological response modifiers such as interleukin-2 or the vascular endothelial growth factor inhibitor bevacizumab [54]; however, as in the case of chronic myelogenous and hairy cell leukemias, more effective forms of therapy for renal-cell cancers are now available [55].