Identification of PTEN/MMAC1 alterations in uncultured melanomas and melanoma cell lines.
A novel tumor suppressor gene, PTEN/MMAC1, has been recently shown to be mutated in gliomas, breast, prostate, kidney cancers and melanomas. Loss-of-heterozygosity studies in melanoma have suggested the presence of at least one chromosome 10q locus lost early in tumor progression. In this study, we screened 45 melanoma cell lines and 17 paired uncultured metastatic melanoma and peripheral blood specimens for PTEN/ MMAC1 alterations using PCR-SSCP and direct sequencing. We found nine melanoma cell lines with homozygous deletions (five with intragenic loss) and four cell lines with mutations (one nonsense and one frameshift; two intronic); from among our uncultured melanoma specimens, we found one tumor with a somatic 17 bp duplication in exon 7 leading to a premature stop codon and one tumor with a possible homozygous deletion. Furthermore, we have identified a novel intragenic polymorphism within intron 4 of PTEN/MMAC1. Taken together, these data suggest that PTEN/MMAC1 may be a chromosome 10q tumor suppressor important in melanoma tumor formation or progression.
Tsao
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H
Department of Dermatology, Massachusetts General Hospital and Dana Farber/Partners CancerCare, Boston 02114, USA.
Zhang
X
X
Benoit
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E
Haluska
F G
FG
D002879:Chromosomes, Human, Pair 10; D005091:Exons; D016147:Genes, Tumor Suppressor; D006801:Humans; D019656:Loss of Heterozygosity; D008545:Melanoma / Q000209:etiology / Q000235:genetics*; D005810:Multigene Family; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D017027:Protein Tyrosine Phosphatases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human