CCNK and lung carcinoma: Moreover, to further investigate whether Cyclin D1 is required for the biological functions of Cyclin K in lung cancer, we transfected exogenously expressed Cyclin D1 into Cyclin K-depleted cells and found that the restoration of Cyclin D1 partially reversed the effects of Cyclin K silencing on cell growth suppression and radiosensitivity (Figure 8B-F).