To understand the expression pattern and prognostic significance of key proteins involved in the G1-to-S phase progression of the cell cycle in stage II-IIIA NSCLC and to investigate whether vorinostat can modulate expression of these proteins, we analyzed the expression patterns of cyclin A2, cyclin D1, cyclin E, and p16 proteins in formalin-fixed paraffin-embedded tissues from 372 patients with stage II-IIIA NSCLC and assessed the effect of vorinostat on their expression in lung cancer cells. The gene discussed is CCNA2; the disease is non-small cell lung carcinoma.