KDR (kinase insert domain receptor) encodes VEGFR2, a receptor tyrosine kinase overexpressed in a variety of solid tumors. Simple variants in KDR are seen in about 2% of all tumors, including 12% of skin tumors, 6% of colorectal tumors, and 3% of lung tumors. VEGFR2 inhibitors are under development and have shown activity in KDR-variant tumors.