MTOR

This review examines established and emerging biomarkers for stratifying patients with early-stage breast cancer to optimize adjuvant systemic therapy. It highlights that while clinicopathological factors remain fundamental, decision-making is increasingly driven by precise biological markers. ER and HER2 status are crucial, and multigene assays refine recurrence risk and chemotherapy benefit in hormone receptor-positive cancers. Immune and DNA-repair biomarkers inform targeted therapies in HER2-positive and triple-negative subtypes, while mutation profiling of genes like ESR1, PIK3CA, AKT, MTOR, and PTEN guides targeted treatments. Emerging approaches, including liquid biopsy and artificial intelligence, offer dynamic insights but require prospective validation.

This study demonstrates that MEK1/2 inhibitors, targeting the Ras-MAPK pathway, induce AXIN1 protein loss in colorectal cancer cell lines and patient-derived organoids. Unlike GSK3 inhibitors, this loss is not attributed to altered AXIN1 protein stability or post-translational modifications, nor to a significant reduction in its transcript levels. Analyses revealed that MEK1/2 inhibitors reduce global protein synthesis via an mTOR-associated pathway, an effect sufficient to cause AXIN1 loss. Co-treatment with tankyrase inhibitors was shown to partially prevent this AXIN1 reduction.