Statistical analysis of normal gastric mucosa, EGC and AGC. (a) Schematic representation and Venn diagram of the sequential statistical analysis performed on normal (NOR), EGC and AGC samples. (b) Hierarchical clustering of 1024 probe sets on 16 normal samples (NOR), nine EGC and 19 AGC. (c) Hierarchical clustering of 369 probe sets on 16 normal samples, nine EGC and 19 AGC. The normal sample of patient ID 18 clustered together with the AGC class, possibly due to the presence of contaminating AGC tumor cells (pT4, N2). Sample code: blue, AGC; red, EGC; light blue, NOR. Grade code: black, G3; dark gray, G2; light gray, G1; white, not applicable (NOR).