Figure 2.

Two-way unsupervised hierarchical clustering of the 230 differentially expressed miRNAs in the 4 tissue types with nonneoplastic mucosa indicated by orange bars, low-grade dysplasia in adenoma by cyan green bars, high-grade dysplasia in adenoma by purple bars, and invasive adenocarcinoma by blue bars. Black represents median expression; pure red, +3 and higher expression; and pure green, −3 and lower expression. Three clusters of tissue types are evident. The first is composed exclusively of nonneoplastic mucosae; the second mainly of nonneoplastic mucosae and low-grade dysplasias in adenomas and a few high-grade dysplasias and adenocarcinomas; and the third mainly of adenocarcinomas with a mixture of low-grade and high-grade dysplasias. The association between these clusters and disease progression represented by the 4 tissue types was highly significant (P < 0.001, Fisher exact test).