The study aimed to create 3D cultures of tumor cells directly from osteosarcoma patients to test personalized treatments based on genetic changes. The research team isolated tumor cells from seven patients and grew them in the laboratory, while simultaneously analyzing the genetic code of the corresponding tumors using whole-exome sequencing. Three of the seven cultures in the collagen hydrogels retained the same genetic changes as the original tumors, but only one culture (L6565) successfully survived long-term cultivation with a success rate of 14 percent. This successful culture showed loss of the CDKN2A gene and was sensitive to the drug palbociclib, which blocks the CDK4 and CDK6 proteins. The results show that more advanced culture methods better reflect tumor heterogeneity and lead to greater variability in treatment response. The study confirms the feasibility of developing personalized treatment approaches for osteosarcoma based on the genetic characteristics of individual patients.