In breast cancer (BRCA), HuR overexpression exhibited a dichotomous relationship: it correlated significantly with resistance to CDK4/6 inhibitors (Palbociclib, Ribociclib; R < -0.3, p < 0.01) while showing positive associations with EGFR inhibitors (Lapatinib, Gefitinib) and chemotherapeutics (Docetaxel, 5-FU; R > 0.25-0.3, p < 0.05). Here, CDK4 is linked to breast carcinoma.