To know if the transcription level of a certain gene (HLA-A, HLA-B or HLA-C) is altered in tumour cells, we should first know what the transcription level is in the normal cells from which these tumours derive.Therefore, in our study we will try to quantitatively measure the locus-specific gene expression of HLA-ABC in normal tissues. In order to perform this measurement we have designed primers that specifically amplify these locus by real-time PCR. The normal tissues chosen were peripheral blood leukocytes and colon and larynx mucosa. In order to select the appropriate cells, thus avoiding interferences, laser microdissection has been performed in both colon and larynx mucosa. Throughout this work we will provide evidence of the specificity of the technique as well as the patterns of gene expression found in the different tissues studied.