As a core scaffold protein, Cullin 7 (Cul7) forms Skp1-Cullin-F-box (SCF) E3 ubiquitin ligase complexes with the regulator of cullins-1 (ROC1), S-phase kinase associated protein 1 (Skp1) and F-Box, and WD repeat domain containing 8 (Fbxw8). Alternatively, Cul7 can form a CRL7SMU1 complex with suppressor of Mec-8 and Unc-52 protein homolog (SMU1), damage-specific DNA binding protein 1 (DDB1), and ring finger protein 40 (RNF40), to promote cell growth. The mutations of Cul7 cause the 3-M dwarf syndrome, indicating Cul7 plays an important role in growth and development in humans and mice. Moreover, Cul7 regulates cell transformation, tumor protein p53 activity, cell senescence, and apoptosis, mutations in Cul7 are also involved in the development of tumors, indicating the characteristics of an oncogene. Cul7 is highly expressed in breast cancer, lung cancer, hepatocellular carcinoma, pancreatic cancer, ovarian cancer, and other malignant tumors where Cul7 promotes tumor development, cell transformation, and cell survival by regulating complex signaling pathways associated with protein degradation. In this review, we discuss the roles of Cul7 in malignant tumor development and its involvement in oncogenic signaling. We finally discuss the potential of Cul7 as a potential significant anti-cancer target.