In fact, many studies have reported that hyper-O-GlcNAcylation often indicates poor prognosis of patients, shorter disease-free survival, and tumor recurrence: Kuo et al. (2021) found that high levels of O-GlcNAcylation was an important independent predictor of poor 10-year DFS for HR lysine demethylase and nuclear receptor corepressor (HR)+/human epidermal growth factor receptor 2 (HER2)-luminal breast cancer, and the predictive effect and potential can be greatly enhanced when combined with pyruvate kinase isoenzyme M2 (PKM2). Here, ERBB2 is linked to breast cancer.