The rarity of HRAS and KRAS Q61R mutants in malignant melanoma let previous investigations erroneously conclude that SP174 is specific for NRAS Q61R-mutant protein.
Integrative sequencing of cutaneous melanoma metastases using different sequencing platforms revealed a new somatic point mutation in HRAS and a structural rearrangement affecting CDKN2C (a CDK4 inhibitor).
We have established a model of melanoma progression in zebrafish through the generation of transgenic lines specifically expressing oncogenic human HRAS in the melanocytic lineage.
We have investigated 37 sporadic malignant melanomas (15 primary cutaneous melanomas and 22 melanoma metastases) and 6 melanoma cell lines for mutations in the 3 Ras genes NRAS, KRAS and HRAS.
HRAS activation by either mutation or copy number increase alone could explain several of the histological features that overlap with those of melanoma.
Loci from these chromosome regions were chosen because of cytogenetic abnormalities reported in melanoma (1p, 6q, 9p), location of common oncogenes (11p-HRAS, 17p-TP53), or use in other MIN studies (5q, 18q).
Nodular melanoma, epithelioid cell type melanoma, and deeply invading melanoma revealed higher reactivity with anti-p21ras monoclonal antibody than the other types.
The results of these studies are (1) 24% of cultured malignant melanomas have activated ras genes, with N-ras being activated ten times as frequently as Harvey (Ha)-ras.
These results imply that hereditary predisposition to melanoma is associated with genes other than the Ha-ras-1 locus, contradicting the original suggestion of Krontiris et al., made on the basis of either an inadequate sample size or other misleading experimental factors.
However, the analysis of the same DNAs for a different polymorphism based on the presence of additional TaqI sites in the variable tandem repeat region of HRAS1 showed that the total frequency of a group of allelic variants, named Tp, was significantly higher in melanoma patients than in normal donors.