Through detecting tumor markers in peripheral blood of 50 ESCC patients before and after radiotherapy and chemotherapy, we found the sensitivity of tumor markers before treatment was 0% (AFP), 0% (CA19-9), 33% (CA72-4), 80% (CEA), 88.9% (CYFRA21-1) and 60% (NSE). This evidence concerns the gene CEACAM5 and esophageal squamous cell carcinoma.