Loss of expression or mutations in the p73 tumour suppressor gene are not involved in the pathogenesis of malignant melanomas

Recently p73, a novel p53 homologous tumour suppressor gene, has been clone d and mapped to chromosome 1p36, Like p53, important functions of p73 in co ntrolling the cell cycle and programmed cell death have been described. Los s of p73 has been demonstrated in neuroblastomas and its involvement in tum origenesis has been suggested to occur in other neuroectodermal cancers. Si nce genetic alterations at the tumour suppressor locus 1p36 have been also identified in malignant melanomas, we investigated the expression of p73 in a panel of nine different human melanoma cell lines, 17 melanocytic naevi, 17 primary malignant melanomas and 20 metastases by reverse transcriptase polymerase chain reaction (PCR) and Southern blotting. We observed signific ant p73 mRNA expression in all the cell lines and tissue specimens except o ne benign melanocytic naevus and one melanoma metastasis, Sequencing the PC R fragments of nine melanoma cell lines derived from primary tumours and fi ve metastases over the entire p73 DNA binding domain revealed wild-type seq uences in all cases. In summary, we conclude that loss of p73 mRNA expressi on or mutations in the p73 DNA binding domain do not represent common genet ic events involved in the pathogenesis of malignant melanomas. (C) 1998 Lip pincott Williams & Wilkins.