Scientists at the Spanish National Cancer Research Centre (CNIO) have developed a genomic test capable of predicting which cancer patients will not respond to chemotherapy. This test identifies specific biomarkers in tumor genetics that indicate resistance to common chemotherapy drugs, enabling oncologists to tailor more effective treatment plans and avoid unnecessary side effects. The test has potential applications across multiple cancer types, including ovarian, breast, prostate, and sarcoma tumors. Research indicates that up to 50% of patients currently do not respond to chemotherapy, underscoring the clinical value of this predictive tool. The development represents a step toward personalized cancer therapy by integrating genetic insights to improve patient outcomes and reduce the burden of ineffective treatments.