CEMIP was initially identified as an inner-ear specific protein in which three-point mutations cause folding changes in protein structure associated with non-syndromic hearing loss. CEMIP was also involved in other cellular activities, such as hyaluronan depolymerization independent of CD44 and other hyaluronidases. Growing evidence has demonstrated that CEMIP is involved in the progression of various tumors. However, whether the oncogenic effects of CEMIP relies on its enzymatic activity remain elusive. CEMIP is significantly related to metastasis and poor prognosis in patients with various tumors, suggesting that CEMIP is a potential, highly specific diagnostic tumor marker. Most preclinical experiments have shown that the overexpression of CEMIP in tumors mainly affects the adhesion, metastasis, and invasion of tumor cells and EMT. Other studies have also demonstrated that CEMIP can promote a variety of tumor processes by affecting tumor proliferation, dedifferentiation, and the tumor microenvironment. In terms of molecular mechanisms, existing research has shown that CEMIP mainly affects the WNT and EGFR signaling pathways. In addition, a variety of miRNAs have been shown to inhibit CEMIP in tumors. This paper elaborates on the clinical characteristics and regulatory dysfunction of CEMIP in different cancers. CEMIP provides a new potential target for therapy of multiple tumors, which is worthy of further study.