Thirty base pair (30 bp) deletion in latent membrane protein 1 oncogene in lymphoepithelial carcinoma of salivary glands

Abstract

To investigate 30 bp deletion of latent membrane protein (LMP)-1 gene in lymphoepithelial carcinoma (LEC) of the salivary glands and to determine the frequency of this deletion. Forty-six cases of salivary gland LEC were investigated by PCR to explore the site specific, 30 bp deletion in the 3' terminal region of LMP-1 gene. To guarantee amplifiable DNA extracted from paraffin-embedded tissue sections, PCR amplification of a house-keeping gene (beta-actin) was performed simultaneously. In addition, DNA sequencing of the PCR product was performed in representative cases. Although amplifiable DNA was obtained in 42 of the 46 specimens, as indicated by beta-actin gene amplification, successful amplification of LMP-1 gene was achieved in 35/42 (83.3%) cases. Two types of PCR products of LMP-1 gene were observed and confirmed by DNA sequencing. A wild-type PCR product (316 bp) was present in 31 cases (88.6%) and only 4 cases (11.4%) showed an aberrant 286 bp PCR product, corresponding to the 3' terminal 30 bp deletion of the gene. Site-specific 30 bp deletion of LMP-1 gene is not a common feature of salivary gland LEC.