During May 2021, Pau Odina, a 13-year-old patient from Vall d'Hebron who had an osteosarcoma, together with his mother, Ma Pilar Suñén, led the http://kmcontraelcancerinfantil.org/index-ca.html #KmContraElCáncerInfantil campaign. With the aim of supporting the Translational Research Group in Child and Adolescent Cancer of the Vall d'Hebron Research Institute (VHIR), they organized a virtual race thanks to which they raised euros 15,000.#KmContraElCáncerInfantil is an initiative that aims to inject funds, but also to raise awareness about the need to invest more resources in childhood cancer research, in addition to promoting physical activity as a means of promoting health. "Reality has exceeded expectations, we are very happy with the great participation, but above all with the affection that we have received throughout these weeks," said Ma Pilar Suñén in a meeting with the Vall d'Hebron researchers. In total, 600 individual participants, 42 teams and 123 solidarity numbers collaborated who reached 13,290 km of race.The proceeds collected will go entirely to the project of the Translational Research Group in Child and Adolescent Cancer of the VHIR led by Dr. Josep Roma and Dr. Soledad Gallego, principal investigators of the team. "We have chosen this project because of our trust to the people who lead it, because of their professionalism and their human qualities. We are convinced that research is the hope for obtaining a cure against childhood cancer", highlights Ma Pilar Suñén. Specifically, the application of liquid biopsy for the early detection of relapses in osteosarcoma is being studied.The objective of this project is that, by means of a blood test (a liquid biopsy), it can be detected if there is circulating tumor cell DNA. In this way, performing liquid biopsy in the follow-up of children and adolescents affected by osteosarcoma will give a more accurate estimation of the risk of relapse, progression of the tumor and metastasis, allowing individualized treatment. According to Dr. Josep Roma, "this strategy will help optimize current therapeutic protocols through the use of molecular biomarkers. We hope that, once the studies are completed, this will have a very direct application in the clinic and lead to a significant improvement in patients' survival". Dr. Roma, together with the rest of researchers from the team, thanked Pau and his family for initiatives such as #KmContraElCáncerInfantil that help promote research in projects like this one.