PTEN and neoplasm: The Cre-loxP system offer spatial and temporal control over the activation of oncogenes or the loss of tumour suppressors, while the CRISPR-Cas9 system enables the rapid, simultaneous editing of key drivers such as Trp53, Nf1, Kras and Pten. These models reproduce key features of human sarcomas, including their histopathology, the initiation of tumours in specific lineages and sites, and tumour–immune interactions within immune-competent hosts.