YL-9, which is designed to retain the synergistic effect on vinorelbine-induced killing activity in NSCLC, may have decreased risk in causing the adverse effects, including melanoma, basal cell carcinoma, and orthostatic hypotension, which may be induced in patients who use PDE5 inhibitors [12,13,14,19]. Here, PDE5A is linked to non-small cell lung carcinoma.