In cancer cells with high HNRNPU expression, on the one hand, HNRNPU localises near the promoter of LMO4 and promotes PI3K/Akt/mTOR signalling by activating transcription; on the other hand, HNRNPU regulates the alternative splicing of MCM10, suppresses nonsense-mediated mRNA decay (NMD) caused by intron retention and activates the Wnt/β-catenin pathway. The gene discussed is LMO4; the disease is cancer.