The Drosophila melanogaster intestine has emerged as a powerful model system for studying the fundamental mechanisms underlying cancer biology, including tumorigenesis, metastasis, and paraneoplastic syndromes such as cachexia. The key signaling pathways implicated in human colorectal cancers play similar roles in the Drosophila intestinal system. Dysregulation of these pathways in the Drosophila intestine leads to overproliferation of intestinal stem cells, loss of cell differentiation, and potential transdifferentiation, mirroring tumorigenic processes in humans. Recent research utilizing Drosophila intestinal tumor models has provided novel insights into how oncogenes and tumor suppressors contribute to the formation and progression of tumors. Models involving activation of oncogenes like mutant Ras and inhibition of tumor suppressors like APC have been instrumental in elucidating mechanisms of tumor cell dissemination, invasion, and collective migration. Furthermore, Drosophila intestinal tumors induce paraneoplastic syndromes such as cancer cachexia and paraneoplastic renal dysfunction, enabling the identification of novel tumor-derived wasting factors, some of which play similar roles in mammals. Thus, the insights gained from Drosophila intestinal tumor models not only deepen our understanding of fundamental cancer biology but also hold promise for informing the development of novel therapeutic strategies for human cancers.