CCND1 and cancer: Metastatic bone tumor: Bone is a primary site for many tumor metastasis.321 The occurrence and metastasis of high-grade and high-stage cancers are associated with the heterogeneity deletion of specific gene loci.322,323 For instance, miR-15a and miR-16-1 are tumor suppressor genes located on chromosome 13q14 and are correlated with the expression of genes like BCL2, CCND1, and WNT3A, which play direct roles in cell survival, proliferation, and invasion processes.324–328 The loss of these genes may facilitate the survival, proliferation, and invasion of cancer cells.