PIK3CA and head and neck squamous cell carcinoma: lncRNAs promote the proliferation of HNSCC cells by modulating the cell cycle by upregulating cyclins and CDKs, suppressing CDK inhibitors, sponging tumor-suppressive miRNAs, activating oncogenic signaling pathways (PI3K/AKT/mTOR, MAPK/ERK), and recruiting epigenetic modifiers to silence cell cycle checkpoints [61].