SEOM clinical guidelines for using molecular markers in clinical practice.

Nowadays, treatment selection for most types of cancers is based on anatomical, histological and clinical criteria, which are defi ned by the selection criteria used in registration phase III trials. However, different cancers present distinct molecular features, so the current approach results in a lack of specificity of cancer therapy, which is associated with decreased efficacy and unnecessary toxicities and costs. Molecular diagnostics has proved able to predict the efficacy of selected targeted therapies. This allows the selection of specific treatments for different types of cancer, increasing their efficiency. Even though the number of treatments for solid tumours that can be selected based on molecular diagnostic tools is limited, much effort is being put into the identification of new biomarkers. This guideline reviews molecular diagnostic biomarkers that allow selection of specific therapies that have obtained regulatory approval as treatment of solid tumours.