RB1 and cancer: While prior research posited genetic or epigenetic factors as potential contributors to low RB1 expression, our analysis of the Cancer Cell Line Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) databases unveiled a strong positive correlation between mRNA and protein levels of RB1 across both TNBC patient cohorts and cell lines, with mutations observed in only a minority of cases (Figure 1D,E).