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). Here, PTEN is linked to lung cancer.