ESTABLISHMENT OF A HUMAN-MELANOMA CELL-LINE LACKING P53 EXPRESSION AND SPONTANEOUSLY METASTASIZING IN NUDE-MICE

Nine human melanoma cell lines established in our laboratory were anal yzed for p53 gene expression and their tumorigenic and metastatic pote ntial in nude mice. Northern blot analyses showed that five of the cel l lines (55%) had either complete loss or low levels of p53 transcript s. Immunocytochemical analysis for p53 protein expression agreed with mRNA analysis results. Nucleotide sequencing showed no mutations in ex ons 5 through 8 of the gene. All cell lines except one gave rise to tu mors at subcutaneous inoculation sites in nude mice. The melanoma cell line UISO-MEL-6, completely lacking p53 expression, spontaneously met astasized to lung and liver in nude mice.