PTEN and lung cancer: miR-21 promotes lung cancer progression through multiple interconnected signaling networks, including the PI3K/AKT, MEK/ERK, TGF-β/SMAD, Hippo, NF-κB, and STAT3 pathways, while also decreasing sensitivity to chemotherapeutic agents like carboplatin, paclitaxel, cisplatin, and gemcitabine by suppressing PTEN and enhancing DNA repair mechanisms [44,45].