CDK4 and neoplasm: Differential gene expression analysis revealed increased levels of tumor-associated calcium signal transducer 2 (TACSTD2) in PC9 cells, consistent with its known modulation during lung adenocarcinoma tumor growth36 (Fig. 5c), and decreased expression of cyclin dependent kinase 4 (CDK4), which is known to enhance sensitivity to EGFR inhibitors37 (Extended Data Fig. 8).