CEACAM5 and neoplasm: Interestingly, we observed that a tumor response occurred in 87.5% of patients with a CYFRA21-1 reduction ≥ 20% already presents after the 1st cycle (p = 0.008) and in 80% of patients with a CEA reduction ≥ 20% already presents after the 2nd cycle (p = 0.033) (data not shown).