The methods used for this narrative review are as follows: the databases used for the search include Web of Science and PubMed; the terms used for the search included CaMK2, CaMK2α, CaMK2β, CaMK2γ, CaMK2δ, or cancer, tumor; the types of literature retrieved from the public databases include bioinformatics articles, experimental articles, and reviews. This evidence concerns the gene CAMK2G and cancer.