In animal models of DLBCL, miR-155 has been shown to block the transforming growth factor (TGF)-β1-induced activation of retinoblastoma protein (RB), thereby promoting dissociation of the phosphorylated RB (pRB)-E2F1 complex and enabling E2F1 to promote gene transcription and cell cycle progression [25]. Here, E2F1 is linked to diffuse large B-cell lymphoma.