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.