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

Abstract

A novel gene, termed p73 with significant homology to p53, has been identified at 1p36, a chromosomal region which is frequently deleted in malignant melanoma. To determine whether p73 is involved in melanoma development we analyzed 8 benign melanocytic nevi, 17 primary melanomas, 34 melanoma metastases and 9 melanoma cell lines for p73 alterations. Allelic loss at the p73 locus was observed in 2 of 10 cases (20%) and occurred only in metastatic tumors. Mutation analysis of the DNA-binding domain of p73 revealed no somatic mutations in the tumor specimens and melanoma cell lines analyzed, whereas the p53 gene was mutated in 5 of 9 melanoma cell lines. Expression analysis of p73 using semiquantitative RT-PCR demonstrated that p73 is not expressed or at exceedingly low levels in benign melanocytic nevi, primary melanomas and lymph node metastases, but at various levels in melanoma cell lines. Our data indicate that p73 does not play a role as a tumor suppressor in melanoma development.