Analysis of N-ras mutations in human cutaneous melanoma: tumor heterogeneity detected by polymerase chain reaction/single-stranded conformation polymorphism analysis.
Determination of the activation state of oncogenes as well as tumor suppressor genes is a main subject of interest in the analysis of the mechanism of tumor initiation. In human melanoma, the c-myc and N-ras oncogenes have been found to be activated in approximately 50% and 15% of the analyzed material, respectively. These studies have mostly been done on fresh tumor material or cell lines. Only in a few cases has an attempt been made to look at tumor heterogeneity or clonality with respect to the activation of oncogenes. We have adjusted the polymerase chain reaction (PCR)/single-stranded conformation polymorphism analysis (SSCP) technique to screen paraffin-embedded melanoma material for the presence of N-ras mutations and found genetic defects at particular progression stages. In one melanoma of the skin, we were able to sublocalize an N-ras mutation in the intraepidermal tumor part, that was absent in the part deeply invading the dermal layer. We conclude that a thorough investigation of N-ras activation in human melanoma should include analysis of histologically different parts of the tumor.
van Elsas
A
A
Department of Clinical Oncology, University Hospital, Leiden, The Netherlands.
Zerp
S
S
van der Flier
S
S
Krüse-Wolters
M
M
Vacca
A
A
Ruiter
D J
DJ
Schrier
P
P
D001483:Base Sequence; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000235:genetics*; D011905:Genes, ras; D006801:Humans; D008545:Melanoma / Q000235:genetics*; D008969:Molecular Sequence Data; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D012878:Skin Neoplasms / Q000235:genetics*
D004273:DNA, Neoplasm