The tumor angiogenesis is a complicated process and involves in many signal pathways, Apln-CreERT:mT/mG mice can be crossed with any gene loss-of-function or gain-of-function mice to study their function on sprouting angiogenesis, and the sprouting angiogenesis ECs can be separated by FACS sorting for detailed cellular function and molecular biology study to find more efficient and less drug resistant medication for therapy of angiogenesis-related diseases as cancer and retinopathy [31]. This evidence concerns the gene APLN and retinal disorder.