Relationship between the expression of RASSF1A and methylation of CpG island A. (A) Expression of RASSF1A in function of the average methylation of 51 CpGs in the CpG island A in 13 PET (black diamond) and matched normal pancreas (white diamond). A linear regression through the data (y = -0.0673x + 2.0228, R2 = 0.337) describes the relationship between methylation and gene expression. Only tumor samples had an average methylation > 40% while all normal tissues had an average methylation < 40%. (B) RASSF1A gene expression vs average methylation of 17 CpGs in the promoter (graph on the left) and vs that of 34 CpGs in the first exon (graph on the right) in PET cases (black diamond) and normal pancreas (white diamond). A linear regression through the data describes the relationship between methylation of promoter (y = -0.0452x + 1.2697, R2 = 0.1314) and first exon (y = -0.0572x + 1.5418, R2 = 0.3569) and gene expression.