After combining both the Dukes and TNM staging systems in the AJCC staging system, we found that syndecan-1 expression was significantly lower in advanced-stage (T3-4 stage) than in early-stage (T1-2 stage) CRC (random-effects model: OR = 2.24, 95 % CI = 1.14 − 4.42; I2 = 63.7 %, P = 0.005). The gene discussed is SDC1; the disease is colorectal carcinoma.