First, we tested the correlation between miR-139-5p and its host gene, PDE2A, among 38 SCLC cell lines and observed a strong correlation between them (r = 0.88) (Fig. 5B), indicating that PDE2A could serve as a reliable surrogate marker for miR-139-5p expression. The gene discussed is PDE2A; the disease is small cell lung carcinoma.