RB1 and breast cancer: As expected, genes down-regulated in RBNSig-BC included key markers of cell cycle control, such as RB1 and CCND1, but also genes from a diverse range of molecular processes including AP-1 transcription factor complex (FOS and FOSB), neuronal system (SLC18A2 and SYT1), hemostasis (SERPINA5, F10, F13A1, and MMRN1), and immunoregulatory signaling (FCER1A, MS4A2, and CD22) (table S3).