WHY: The heterogeneity of tumors often makes their diagnosis and treatment a very hard task. A single tumor can have many different diagnostically-relevant molecular markers which can also be used to monitor the efficacy of treatment. Innovative, simple, cost-effective, and quantitative analytical tools for diagnostic and therapeutic applications are urgently needed to ensure rapid and appropriate patient care. WHAT: CO-TRANS-NET project addresses this need by developing synthetic nucleic acid units that can respond to a wide range of tumor biomarkers and can provide innovative tools for biosensing and therapeutics through cell-free in-vitro transcription. HOW: The ground-breaking idea of CO-TRANS-NET is to harness the high programmability of synthetic nucleic acids together with the high sensitivity and versatility of cell-free systems to develop co-transcriptional networks that, in one pot, through nature-inspired recognition mechanisms, can respond to a variety of targets including proteins, small molecules and antibodies and trigger in-vitro transcription of functional RNA. The transcribed RNA can provide a measurable signal or produce a therapeutic drug. CO-TRANS-NET aims to develop single theranostic nanodevices in which cancer diagnosis and theraphy can be simultaneously achieved- This goes beyond the state of the art and represents a breakthrough in the field of diagnostics, biosensing, synthetic biology and nucleic acid-based therapeutics.