CCND1 and cancer: Gene amplification is the main mechanism of CCND1/cyclin D1 upregulation in cancer [19,20,21], although in melanoma, other genetic alterations seem to be also involved in the dysregulation of the cyclin D1 function, including mutations, polymorphisms, chromosomal translocations, and the activation of several oncogenic pathways (MAPK, PI3K, Wnt, NF-κβ) [22].