RNA-seq analysis revealed that cordycepin affected vitamin D metabolism, lipid transport, and proteolysis in cellular protein catabolic process pathways in the SCLC brain metastasis microenvironment of zebrafish, regulating the expression of key genes such as cyp24a1, apoa1a, and cathepsin L. The anti-brain metastasis effect of cordycepin in SCLC was mediated by reversing the expression of these genes [199]. The gene discussed is CYP24A1; the disease is small cell lung carcinoma.