Excess lactate can enter the nucleus and induce histone lactylation, and this modification is catalyzed by the p300 enzyme, altering gene expression to promote tumor growth, for example, elevated histone H3 lysine 18 lactylation (H3K18la) levels in bladder cancer cells promote the expression of key transcription factors YY1 and YBX1, in which YBX1 plays a role in promoting DNA repair; YY1 can upregulate DNA repair genes (such as PTEN and Rad51), multidrug resistance genes (MDR1/ABCB1), and others, together leading to the chemotherapy resistance of tumor cells [44]. The gene discussed is YY1; the disease is urinary bladder cancer.