β2-microglobulin gene mutation is not a common mechanism of HLA class I total loss in human tumors
| Autor: | Francisco Ruiz-Cabello, M.A. Fernandez, Federico Garrido, Pilar Jiménez, M. R. Oliva, Teresa Cabrera, M. A. Lopez Nevot |
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| Rok vydání: | 2000 |
| Předmět: |
Skin Neoplasms
Clinical Biochemistry Loss of Heterozygosity Human leukocyte antigen Gene mutation Biology medicine.disease_cause Loss of heterozygosity Neoplasms medicine Humans Point Mutation Melanoma Gene Polymorphism Single-Stranded Conformational Genetics Mutation Beta-2 microglobulin Point mutation Histocompatibility Antigens Class I Molecular biology Stop codon Phenotype Urinary Bladder Neoplasms Head and Neck Neoplasms Colorectal Neoplasms beta 2-Microglobulin Gene Deletion |
| Zdroj: | International Journal of Clinical & Laboratory Research. 30:87-92 |
| ISSN: | 1434-4467 0940-5437 |
| DOI: | 10.1007/bf02874164 |
| Popis: | One hundred and sixty-two tumor samples were analyzed for HLA class I expression using immunohistological techniques. HLA class I total loss (phenotype no. I) was detected in 31 cases (19%), comprising 20 colorectal, 3 laryngeal, and 2 bladder carcinomas and 6 melanomas. Twenty-one cases were selected for molecular analysis due to a higher proportion of tumor cells versus stroma cells (75%). We investigated whether beta2-microglobulin mutation was responsible for HLA downregulation. Single-strand conformation polymorphism and sequencing analysis of DNA samples was performed. Alterations were detected only in melanomas M78 (a point mutation in the initiation ATG sequence), M79 (a mutation in codon 31 producing a stop codon), and M34 (a TTCT deletion introducing a termination codon signal). We found no beta2-microglobulin gene mutation in the other 18 samples. Loss of heterozygosity in 15q close to the beta2-microglobulin gene was found in 5 cases. We conclude that HLA class I total loss can frequently occur without beta2-microglobulin gene mutations. |
| Databáze: | OpenAIRE |
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