Tandem duplications events were also frequent in metastatic cancers, involving: an enhancer, amplified in 87% of castration-resistant metastatic patients, that can act independently of androgen receptor locus amplification to increase expression of androgen receptor in response to androgen deprivation therapy; intergenic regions near MYC at 8q24 and FOXA1 at 14q13.3 are targets of structural variation and determine tandem duplication events, contributing to increase MYC and FOXA1 expression [68]. This evidence concerns the gene FOXA1 and metastatic malignant neoplasm.