However, our study showed pretreatment CEA ≥10 ng ml-1 was the only independent risk factor for chemotherapy-associated lymphopenia <0.66 × 109/L, and age >60 years was the only independent risk factor for chemotherapy-associated lymphopenia <0.91 × 109/L in colorectal cancer, suggesting those who have a pretreatment CEA ≥10 ng ml-1 are predispose to lymphopenia <0.66 × 109/L, meanwhile those >60 years old are predispose to lymphopenia <0.91 × 109/L during adjuvant chemotherapy. The gene discussed is CEACAM5; the disease is lymphopenia.