EGFR and neoplasm: Pharmacologically, miR‐21 regulation also shares some signaling pathways which could enhance or remedy the therapeutic mechanisms by chemotherapies such as tyrosine kinase inhibitors (TKIs).[54, 55] Research showed that treatment with TKIs could recover PTEN expression in lung cancer cells.[56] However, EGFR‐mutant lung cancer would develop TKI drug resistance by suppressing PTEN expression.[57] Here, treatment with QTPlus‐AM21 could promote PTEN expression and inhibit EGFR levels in A549 cells in vitro and the TME from A549 tumor‐bearing nude mice (Figure 4).