Integrins, a group of heterodimer receptors for cell-matrix and cell-cell adhesion, mediate various intracellular activities, including cell migration, polarity, survival, growth, and death. Multiple types of integrins are differentially expressed in various cancers during different stages of progression, which are involved in the regulation of cancer cell proliferation, invasion, migration, and angiogenesis. The crucial roles of integrins in tumor progression provide valuable clues for cancer diagnosis and targeted therapy. Numerous integrin inhibitors have been investigated in clinical trials to explore effective regimens and minimize side effects. Given the complexity of the integrin-mediated tumor-promoting effect, challenges and difficulties remain in the research and development of integrin inhibitors, which seriously restrict the efficacy and application of integrin-targeted therapy. Novel targeted therapy of integrins, however, is beneficial for patients as a potential avenue forward, which needs better pharmacological effect, valid experimental models, and in-depth understanding of integrins. This review provides the insight needed to elucidate the mechanisms underlying cancer progression and novel protocols for the clinical treatment of cancer.