P53 MUTATION AND C-FOS OVEREXPRESSION ARE ASSOCIATED WITH DETECTION OF THE ANTIGEN VLA-2 IN HUMAN-MELANOMA CELL-LINES

In this study, we examined the expression of c-fos, c-myc, mutant c-Ha -ras and mutant p53 proteins in three normal human melanocyte cell lin es and the following 12 melanoma cell lines: M5, Mewo, A375, Bro, Mel 2a, O-Mel II, IgR 39, SkMel-13, -19, -28 Mel-57 and NKI-4, using an im munohistochemical assay (APAAP). An effort was made to correlate oncog ene expression with growth parameters, differentiation antigens (HMB-4 5, vla-2, k.1.2.58, HLA-DR, HLA-I), and pigmentation. All melanocyte c ell lines were negative for the oncogenes examined, whereas six of the melanoma cell lines were found also positive (three for c-fos, two fo r c-myc, one for c-Ha-ras, and four for p53). Three melanoma cell line s expressed one oncogene and three the combination c-fos/p53. These th ree melanoma cell lines were positive for the ''late'' tumor progressi on marker A.1.43 (vla-2 adhesion molecule) and negative for the differ entiation marker k.1.2.58. Positivity for A.1.43 combined with negativ e staining for k.1.2.58 was found in six out of the 12 cell lines. The observed oncogene expression correlated neither with growth parameter s nor melanin content. The present findings revealed a coexpression of mutant p53 and c-fos proteins being associated with a highly malignan t phenotype in melanoma cell lines. Further studies are necessary to c larify the significance of the above findings.