The chorioallantoic membrane (CAM) model, generated during avian development, can be used in cancer research as an alternative in vivo model to perform tumorigenesis in ovo due to advantages such as simplicity, low cost, rapid growth, and being naturally immunodeficient. The aim of this systematic review has been to compile and analyze all studies that use the CAM assay as a tumor induction model. For that, a systematic search was carried out in four different databases: PubMed, Scopus, Cochrane, and WOS. After eliminating duplicates and following the established inclusion and exclusion criteria, a total of 74 articles were included. Of these, 62% use the in ovo technique, 13% use the ex ovo technique, 9% study the formation of metastasis, and 16% induce tumors from patient biopsies. Regarding the methodology followed, the main species used is chicken (95%), although some studies use quail eggs (4%), and one article uses ostrich eggs. Therefore, the CAM assay is a revolutionary technique that allows a simple and effective way to induce tumors, test the effectiveness of treatments, carry out metastasis studies, perform biopsy grafts of patients, and carry out personalized medicine. However, unification of the methodology used is necessary.

Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma in children, constitutes approximately 40% of all recorded soft tissue tumors and is associated with a poor prognosis, with survival rates of less than 20% at 3 years. The development of resistance to cytotoxic drugs is a primary contributor to therapeutic failure. Consequently, the exploration of new therapeutic strategies is of vital importance. The potential use of plant extracts and their bioactive compounds emerges as a complementary treatment for this type of cancer. This systematic review focuses on research related to plant extracts or isolated bioactive compounds exhibiting antitumor activity against RMS cells. Literature searches were conducted in PubMed, Scopus, Cochrane, and WOS. A total of 173 articles published to date were identified, although only 40 were finally included to meet the inclusion criteria. Furthermore, many of these compounds are readily available and have reduced cytotoxicity, showing an apoptosis-mediated mechanism of action to induce tumor cell death. Interestingly, their use combined with chemotherapy or loaded with nanoparticles achieves better results by reducing toxicity and/or facilitating entry into tumor cells. Future in vivo studies will be necessary to verify the utility of these natural compounds as a therapeutic tool for RMS.