MIR21 and neoplasm: To identify key tumor-suppressive factors directly inhibited by miR-21-5p in primary tumors and LUAD-derived cells, the correlation of mRNA expression with miR-21 in LUAD was determined for mRNAs with predicted miR-21-5p target sites that were differentially expressed in A549 cells upon deletion of MIR21 (Figure 3C; Supplementary Table S6).