Fecal Hb alone had the best sensitivity (78.6%), specificity (85.1%), positive predictive value (PPV, 61.1%), and negative predictive value (NPV, 93%) for detecting colorectal cancer (P < 0.001); and the positive impact of adding fecal Cp and Lf was limited (Table 3). The gene discussed is GSTM1; the disease is colorectal cancer.