Fig. 6: Integrated model of RPS24 AS regulation and its clinical implications in breast cancer.

The schematic summarizes regulatory mechanisms and clinical implications of the RPS24 ex4:3 bp isoform in ER⁺ breast cancer. Inclusion of the 3-bp microexon (ex4:3 bp isoform) is repressed by PTBP1 binding to intronic regions, while ER signaling and cell cycle/growth pathway inhibition (via mTOR and CDK4/6 inhibitors) promote its expression. The ex4:3 bp isoform is downregulated in drug-resistant and metastatic cells but upregulated in response to targeted therapy, acting as a dynamic biomarker. High ex4:3 bp expression is associated with ER⁺ status, increased epithelial differentiation and sensitivity to treatment, while reduced expression correlates with drug resistance and metastatic potential. This isoform therefore serves as a predictive marker for therapeutic response and disease progression in breast cancer.