Interestingly, in the clinical cases with low p18INK4C expression (defined as a less than 2-fold decrease in GC tissues compared with adjacent non-tumor tissues), the p18INK4C promoter showed significantly higher methylation levels in tumor tissues than in adjacent non-tumor tissues, indicating a negative correlation between DNA methylation and p18INK4C expression (P < 0.05; Fig. 4d). Here, CDKN2C is linked to neoplasm.