CCND1 and lung cancer: Overall, the downregulation of CCND1 exhibited remarkable antitumor efficacy and developed the synergistic antitumor effects with FGFR1 inhibitor in vitro and in vivo, which provides strong evidence that CCND1 can serve not only as a prognostic marker, but also as a vital target in therapies against FGFR1-amplified lung cancer.