High frequency of altered HLA class I phenotypes in laryngeal carcinomas.

The exact frequency of HLA class I losses in human tumors is unknown. We have previously shown that primary breast and colorectal carcinomas frequently lose HLA class I molecules (88% and 73%, respectively). Now we report that this phenomenon is also a frequent event in laryngeal carcinomas. Of a total of 76 laryngeal carcinomas analyzed, 66% of the tumors showed an alteration in HLA class I phenotype. These altered HLA phenotypes were classified as total HLA loss (10.52%) (phenotype I); HLA-A locus-specific loss (13.15%) (phenotype IIIa); HLA-B locus-specific loss (10.52%) (phenotype IIIb); HLA allelic loss (27.63%) (phenotype IV); and HLA-A and B locus loss (3.9%). Comparison of histopathological parameters with HLA expression showed that poorly differentiated tumors had the lowest levels of HLA class I expression (p < 0.05).