Table 4. A description of tumor specimens by stage for discovery tissues.

TX stage	T1	T2	T3	T4	TIS	TX
Specimens	3	24	94	18	1	21

T stage detail (from TNM staging) for the specimens used for discovery by Affymetrix gene expression analysis. TX No description of the tumor's extent is possible because of incomplete information. Tis The cancer is in the earliest stage (in situ). It involves only the mucosa. It has not grown beyond the muscularis mucosa (inner muscle layer).T1 The cancer has grown through the muscularis mucosa and extends into the submucosa. T2 The cancer has grown through the submucosa and extends into the muscularis propria (thick outer muscle layer). T3 The cancer has grown through the muscularis propria and into the outermost layers of the colon or rectum but not through them. It has not reached any nearby organs or tissues. T4 The cancer has grown through the serosa (also known as the visceral peritoneum), the outermost lining of the intestines and may have grown through the wall of the colon or rectum to attach or invade nearby tissues.