Because of the greater number of samples available from the matched tissues, we further examined the effect of other patient characteristics, gender (male versus female), smoking status (smoker versus nonsmoker), and patient outcome (alive versus dead), on mean differences in Id1 expression levels with respect to each tissue type, adenocarcinoma, squamous cell carcinoma, and other (Table 3). The gene discussed is ID1; the disease is adenocarcinoma.