To explore the biological functions of CASC9 in the sensitivity of NSCLC cells, we transfected PC9/GR cells with CASC9-specific small interfering RNA (siRNA) to diminish its expression (Fig. 2a), and a CASC9 overexpression vector was transfected into parental PC9 cells to upregulate its expression (Fig. 2b). Here, CASC9 is linked to non-small cell lung carcinoma.