Epigenetic loss of mucosa-associated lymphoid tissue 1 expression in patients with oral carcinomas.
Mucosa-associated lymphoid tissue 1 (MALT1), which is located in a genomic region that encodes unknown tumor suppressor gene(s), activates nuclear factor-kappaB in lymphocyte lineages. However, its expression and role in the pathology of malignant tumors of epithelial origin is not known. In the present study, we examined MALT1 expression and its implications for the pathology of oral carcinomas. Immunostaining localized MALT1 in the nucleus of normal oral epithelial cells, but the expression was absent in 45.0% of carcinomas (49 of 109 cases) especially at the invasive front. The loss of expression was correlated with tumor recurrence (P = 0.007) and poor patient survival (P < 0.001), and it was an independent prognostic determinant (P < 0.001). MALT1-negative carcinomas exhibited microsatellite instability at the MALT1 locus and a specific cytosine methylation positioned at -256 from the gene, and the expression was recovered by demethylation treatment. In contrast to lymphocyte lineages, carcinoma cells showed MALT1 located at the nucleus independent of its domain structures, and its loss of expression induced the epithelial-mesenchymal transition. These results show that MALT1 is expressed in the nucleus of oral epithelial cells and that its expression is epigenetically inactivated during tumor progression, suggesting that the detection of MALT1 expression is a useful predictive and prognostic determinant in the clinical management of oral carcinomas.
Chiba
Tadashige
T
Department of Biochemistry, School of Life Dentistry at Tokyo, The Nippon Dental University, Chiyoda-ku, Tokyo, Japan.
Maeda
Genta
G
Kawashiri
Shuichi
S
Kato
Koroku
K
Imai
Kazushi
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D020169:Caspases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D019175:DNA Methylation; D004789:Enzyme Activation; D005260:Female; D042822:Genomic Instability; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic
D009363:Neoplasm Proteins; D020169:Caspases; C400109:MALT1 protein, human; D000074884:Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Protein