Positive CK20 expression in peripheral blood postoperatively was closely related to tumordiameter (P = 8.271 × 10−9), Borrmann type (P= 1.559 × 10−4), invasive depth (P = 1.212 × 10−8),lymphatic metastasis (P = 1.739 × 10−10), microvessel invasion(P = 5.600 × 10−11), and cancer-related antigens, includingCEA (P = 3.064 × 10−5), CA724 (P = 7.852 ×10−6), and CA199 (P = 2.805 × 10−6). This evidence concerns the gene KRT20 and cancer.