Hypermethylation of a 5' CpG island of p16 is a frequent event in non-Hodgkin's lymphoma.
Hypermethylation of a 5' CpG island of p16 gene has been recently described as a possible way of inactivation of this tumor suppressor gene, alternative to deletions and mutations. We have investigated if hypermethylation of a 5' CpG island of p16 occurs in non-Hodgkin's lymphoma (NHL) and normal lymphoid tissue. A total of 82 NHLs were examined for p16 methylation by Southern blot and PCR analysis. Hypermethylation was detected in approximately 20% of B cell lymphomas of both low and high grade and in 15% of T cell NHL. The highest rate of p16 gene methylation in tumors was found among MALT (mucosa-associated lymphoid tissue) lymphomas in which the percentage of cases with p16 gene methylation reached 67%. However, normal lymphoid tissue was always unmethylated at p16 locus. These results indicate that p16 gene methylation is a frequent event in NHLs, mainly in MALT lymphomas, and suggest that it could be an important mechanism of inactivation of this gene.
Martinez-Delgado
B
B
Genetic Department, Fundación Jiménenz Díaz, Madrid, Spain.
Fernandez-Piqueras
J
J
Garcia
M J
MJ
Arranz
E
E
Gallego
J
J
Rivas
C
C
Robledo
M
M
Benitez
J
J
D001665:Binding Sites; D015139:Blotting, Southern; D002352:Carrier Proteins / Q000235:genetics*; D019941:Cyclin-Dependent Kinase Inhibitor p16; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000378:metabolism*; D005091:Exons; D015972:Gene Expression Regulation, Neoplastic; D016147:Genes, Tumor Suppressor; D006801:Humans; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000378:metabolism; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics / Q000378:metabolism; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics* / Q000378:metabolism*; D016399:Lymphoma, T-Cell / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction
D002352:Carrier Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm