CEACAM5 and adenocarcinoma: Finally, analyzing the tumor markers on the basis of histotype we observed that patients with adenocarcinoma reached a DCR when CEA and CYFRA21-1 reduction was ≥ 20%, with a significant difference in response compared to the patients with marker reduction < 20% (CEA, 77% vs 40%, p = 0.043; CYFRA21-1, 92% vs 35%, p = 0.001).