Lack of p73 mutations and late occurrence of p73 allelic deletions in melanoma tissues and cell lines

A novel gene, termed p73 with significant homology to p53; has been identif ied at 1p36, a chromosomal region which is frequently deleted in malignant melanoma. To determine whether p73 is involved in melanoma development we a nalyzed 8 benign melanocytic nevi, 17 primary melanomas, 34 melanoma metast ases and 9 melanoma cell lines for p73 alterations. Allelic loss at the p73 locus was observed in 2 of I 9 cases (20%) and occurred only in metastatic tumors. Mutation analysis of the DNA-binding domain of p73 revealed no som atic mutations in the tumor specimens and melanoma cell lines analyzed, whe reas the p53 gene was mutated in 5 of 9 melanoma cell lines. Expression ana lysis of p73 using semiquantitative RT-PCR demonstrated that p73 is not! ex pressed or at exceedingly low levels in benign melanocytic nevi, primary me lanomas and lymph node metastases, but at various levels in melanoma cell l ines. Our data indicate that p73 does not play a role as a tumor suppressor in melanoma development. (C) 1999 Wiley-Liss, Inc.