Fibromodulin (FMOD), an ECM small leucine-rich proteoglycan (SLRP), was reported to promote angiogenesis not only during wound healing, but also in optical and cutaneous angiogenesis-dependent diseases. The autocrine FMOD of cancer cells may promote tumor angiogenesis of SCLC by upregulating the expression of angiogenic factors that act in concert to facilitate the angiogenic phenotype of endothelial cells as a proangiogenic factor. Therefore, silencing FMOD may be a potentially clinical therapy for repressing tumor angiogenesis.