The Medicinal Chemistry Section is a key component of the Experimental Therapeutics Programme (ETP) at CNIO, dedicated to the identification, design, and optimisation of small molecules with relevant activity against cancer targets. Acting as a bridge between basic cancer research and the pharmaceutical industry, we develop molecules aimed at validated targets and assess their potency and mechanism of action through in vitro assays and in vivo proof-of-concept studies. Beyond classical inhibitors, we also pursue alternative strategies, such as targeted protein degradation (e.g., PROTACs) and engage in chemical biology approaches to discover novel targets through phenotypic screening. Additionally, we provide high-quality chemical tools and reference compounds to support mechanistic studies and phenotype interrogation. Collaboration — both within CNIO and with external partners — is central to our mission of translating scientific discoveries into innovative therapeutic opportunities.