Spatial transcriptomics is a cutting-edge technology that allows the simultaneous visualization of the spatial distribution of gene expression and histological features in tissue samples. In the field of cancer biology, spatial transcriptomics has the potential to unravel complex biological processes that contribute to tumor development, progression, and response to treatment. Herein, I will discuss how

analyzing the gene expression profiles of cancer cells within their microenvironment and maintaining the tissue architecture, spatial transcriptomics can be used to identify and characterize key cancer hallmarks, such as angiogenesis, immune evasion, and tissue invasion. This information can help researchers better understand the mechanisms underlying tumor growth and develop novel targeted therapies. Spatial transcriptomics can also be a promising tool to improve cancer diagnosis and treatment, where I will explain the example of the biology and prediction-of-origin in cases of cancer of unknown primary (CUPs). By analyzing the spatial distribution of gene expression patterns in CUPs, we open the door to tailor treatment accordingly. Finally, I will introduce how we iused spatial transcriptomics to investigate the location of the cellular and molecular changes that occur in other diseases, such as in the lung tissue of COVID-19 patients. Initial data suggest that important insights into the immune response and tissue damage caused by the virus, including the identification of cellular and molecular scars left by lethal COVID-19 in the lung, can be obtained. Overall, spatial transcriptomics holds great potential for advancing our understanding of cancer biology, improving diagnosis and treatment, and shedding light on other diseases such as COVID-19.