FIGURE 6.

SirT1 expression is heterogenous in adenocarcinomas. Human colon tumor tissue array was stained for SirT1 using 10E4. a, intensity of SirT1 stain in different tumors ranged from 0 (no stain) to 3 (overexpression). b, pie representation of SirT1 levels correlated with stage of cancer. SirT1 level is moderate to high (level 2) in normal colonic mucosa and most adenomas. Tumors of different adenocarcinoma stages exhibit variable expression pattern of SirT1. While some tumors overexpress SirT1 (level 3), some down-regulate SirT1 (level 0 or 1). Level 3 expression is infrequent in stage IV tumors.