I am a DEVELOPMENTAL BIOLOGIST, fascinated by how cells interact with each other, to deliver instructions, to collaborate, to compete or synchronize their actions. During my PhD I studied the NOTCH signaling during early neurogenesis, with Domingos Henrique (iMM, PT). Then for my Post-Doc, I started working with the zebrafish model with Leonor Saúde (iMM, PT) and Julian Lewis (FRS, CR-UK). During this work I found a transcription based negative feedback-loop that allows the coordination of 3 major events during embryonic segmentation: DIFFERENTIATION, CELL MOVEMENT and STEM CELL . By the end of my Post¿Doc I became interested in cancer. I was propelled into CANCER RESEARCH when I realized that in a time of astonishing technology, in general, oncologists do not have a test to choose the best treatment for each individual patient. Thus, many times, patients go through trial-and-error approaches, subjected to unnecessary toxicity. THIS WAS A PERSONAL WAKE-UP CALL to establish an in vivo personalized test for chemotherapy (Fior et al, PNAS 2017). I started by challenging the zebrafish xenograft model, to test if it could reveal inter- and intra- patient tumor heterogeneity (Fior et al PNAS 2017). We performed a direct comparison between zebrafish and mouse xenografts and successfully showed similar responses. In this study, we demonstrated the feasibility of using primary patient samples for zAvatar generation and provided proof-of-concept experiments showing that response to chemotherapy in zAvatars correlates with patient clinical response (Fior et al PNAS 2017). This work received major coverage from the scientific community (Science by M.Leslie 2017, PNAS by Fazio & Zon, 2017) and social media (National Geographic, Independent etc¿) and is now considered a milestone in the field, as highlighted in a recent Nature Review in Cancer by Zon & colleagues, 2020. Currently, we are testing the predictiveness of the zAvatars model by conducting co-clinical trials, i.e. comparing the clinical response in patients with their matching zAvatars. We are developing and testing the model in several types of cancers and settings: colorectal (expanding the original cohort, Costa et al in prep), in rectal cancer (neoadjuvant radio-chemotherapy, Costa et al EBiomedicine 2019), pancreatic cancer (Tavares Barroso et al Cells 2021), breast (Mendes et al, in prep) and ovarian cancer (Estrada et al, in prep). In parallel, to this translational work, I made key discoveries that reveal intriguing cell-cell interactions between tumour cells and zebrafish innate immunity, bringing me back to more fundamental questions of cell-cell communication, with a strong translational impact. We found that human tumor cells are able to reconstitute different tumor microenvironments (TMEs), revealing their HOT/COLD state. In other words, we think zebrafish xenografts can be reporters of the TME state (Póvoa et al, Nat.comm 2021), opening a whole new avenue of research in my Lab that I am very excited to pursue in parallel to the translation of the zAvatars to the clinic. TEACHING During my research career, I have been regularly invited by my peers to give lectures in prestigious PhD (Instituto Gulbenkian Ciência and PGCD/Cape Verde) and Master programs (Faculty of Sciences, Faculty of Medicine, U Lisbon). I was also invited to design and lecture 2 Master courses, one in Developmental Biology (NOVA School of Science & Technology 2010-2016) and another in Molecular and Cell Biology of Cancer (Faculty of Sciences, 2015-2019). In this course I tried to blend development, evolution and clinical perspectives in a series of seminars. This Cancer course is now available in a form of TEXTBOOK (Fior and Zilhão 2019 Molecular and Cell Biology of Cancer, Springer).