Statistically significant differences in hematological and blood chemistry parameters in dogs with multicentric lymphoma treated with the COP protocol were detected between the pre-treatment and 4 weeks post-treatment periods, especially lymphocyte count (p = 0.022), monocyte count (p = 0.039), platelet count (p = 0.009), ALP (p = 0.016), BUN (p = 0.017), creatinine (p < 0.001), globulin (p = 0.001), albumin (p < 0.001), PLR (p = 0.013), and AGR (p < 0.001). The gene discussed is ALB; the disease is lymphoma.