Loss of single HLA class I allospecificities in melanoma cells due to selective genomic abbreviations

Int J Cancer. 2002 May 1;99(1):82-7. doi: 10.1002/ijc.10284.


Expression of human leucocyte antigen (HLA) Class I molecules is essential for the recognition of malignant melanoma (MM) cells by CD8(+) T lymphocytes. A complete or partial loss of HLA Class I molecules is a potent strategy for MM cells to escape from immunosurveillance. In 2 out of 55 melanoma cell cultures we identified a complete phenotypic loss of HLA allospecificities. Both patients have been treated unsuccessfully with HLA-A2 peptides. To identify the reasons underlying the loss of single HLA-A allospecificities, we searched for genomic alterations at the locus for HLA Class I alpha-chain on chromosome 6 in melanoma cell cultures established from 2 selected patients with MM in advanced stage. This deficiency was associated with alterations of HLA-A2 gene sequences as determined by polymerase chain reaction-sequence specific primers (PCR-SSP). Karyotyping revealed a chromosomal loss in Patient 1, whereas melanoma cell cultures established from Patient 2 displayed 2 copies of chromosome 6. Loss of heterozygosity (LOH) using markers located around position 6p21 was detected in both cases. By applying group-specific primer-mixes spanning the 5'-flanking region of the HLA-A2 gene locus the relevant region was amplified by PCR and subsequent sequencing allowed alignment with the known HLA Class I reference sequences. Functional assays using HLA-A2-restricted cytotoxic T-cell clones were performed in HLA-A2 deficient MM cultures and revealed a drastically reduced susceptibility to CTL lysis in HLA-A2 negative cells. We could document the occurrence of selective HLA-A2 deficiencies in cultured advanced-stage melanoma metastases and identify their molecular causes as genomic alterations within the HLA-A gene locus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Antigens, Neoplasm / genetics*
  • Chromosomes, Human, Pair 6 / genetics
  • Flow Cytometry
  • Genes, MHC Class I / genetics
  • HLA-A2 Antigen / genetics*
  • Humans
  • Karyotyping
  • Loss of Heterozygosity*
  • Melanoma / genetics*
  • Melanoma / immunology
  • Middle Aged
  • Polymerase Chain Reaction
  • Polymorphism, Single-Stranded Conformational
  • Sequence Analysis, DNA
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / immunology
  • T-Lymphocytes, Cytotoxic / immunology
  • Tumor Cells, Cultured


  • Antigens, Neoplasm
  • HLA-A2 Antigen