Table 1. Frequency of various molecular alterations in different types of melanocytic tumors.

Molecular alterations	Spitz nevi	AST	Spitzoid MM	Congenital nevi	Acquired nevi	Melanomas	Blue nevus like MM	Blue nevi
NRAS	0–5%	0–25%	0–25%	Large/giant: 95%, small/medium: 70%	6%	25% primary cutaneous mm		0–1%
HRAS	15–20%	14%	0%			<1%
BRAF	0–20%	0–25%	0–25%	Large/giant: 5%, small/medium: 30%	78–81%	80% primary mm, 68% metastatic mm	25%	0–12%
BAP1		15%				4% uveal, 1.5% family history of cutaneous mm	17%
CDKN2a		Homozygous deletion of 9p21 more aggressive than heterozygous deletion				5–72% (sporadic 1%, family history 9%, geographical areas 13–91%)
TERT-p						22–71%
Kit fusions	55%	56%	39%			Acral & mucosal
ALK	8%	5%	1%
GNAQ						Uveal	25%	67–82%
GNA11						Uveal	33%	0–8%

AST, atypical Spitz tumor; MM, malignant melanoma.