Paraspeckles are important subnuclear bodies in the nucleus. They can regulate gene expression by holding RNA or protein and interacting with miRNA, thus playing important roles in the development and progression of cancers. Studying the biological structure and function of paraspeckles in cancer cell is crucial for the diagnosis and treatment of cancers; however, the structure, function, and clinical significance of paraspeckles in cancer cell are still elusive. This paper reviews the composition, structure, and assembly of paraspeckles, and its mechanisms and clinical significance in the development and progression of cancers, so as to provide research directions and clues for the tumor diagnosis, treatment, and prognosis.