RELATIONSHIP BETWEEN DNA METHYLATION AND GENE-EXPRESSION OF THE HOXB GENE-CLUSTER IN SMALL-CELL LUNG CANCERS

The expression pattern of the HOXB gene cluster in four xenografted sm all-cell lung cancers was compared to the methylation of the DNA in th e corresponding genomic regions, In 90% (17/19) of the studied cases, the expressed genes were in methylated regions,whereas 70% (12/17) of the unexpressed genes were in unmethylated regions, This specific beha vior could correspond to a particular gene expression regulation mecha nism of the HOX gene network, Since some genes (HOXB2, HOXB4, HOXB7) w ere always inactive when unmethylated, this unexpected relationship mi ght indicate their keg function(s) in the HOX gene network.