AIM: To evaluate and compare detection of lymphatic and blood vessel invasion (LVI and BVI) by hematox-ylin-eosin (HE) and immunohistochemistry (IHC) in gastric cancer specimens, and to correlate with lymph node status. METHODS: IHC using D2-40 (a lymphatic endothelial marker) and CD34 (a pan-endothelial marker) was performed to study LVI and BVI in surgical specimens froma consecutive series of 95 primary gastric cancer cases. The results of the IHC study were compared with the detection by HE using McNemar test and kappa index. The morphologic features of the tumors and the presence of LVI and BVI were related to the presence of lymph node metastasis. A χ2 test was performed to obtain associations between LVI and BVI and other prognostic factors for gastric cancer. RESULTS: The detection rate of LVI was considerably higher than that of BVI. The IHC study identified eight false-positive cases and 13 false-negative cases for LVI, and 24 false-positive cases and 10 false-negative cases for BVI. The average Kappa value determined was moderate for LVI (k=0.50) and low for BVI (k=0.20). Both LVI and BVI were statistically associated with the presence of lymph node metastasis (HE: P=0.001, P=0.013, and IHC: P=0.001, P=0.019). The mor-phologic features associated with LVI were location of the tumor in the distal third of the stomach (P=0.039), Borrmann’s macroscopic type (P=0.001), organ inva-sion (P=0.03) and the depth of tumor invasion (P=0.001). The presence of BVI was related only to the depth of tumor invasion (P=0.003). CONCLUSION: The immunohistochemical identification of lymphatic and blood vessels is useful for increasing the accuracy of the diagnosis of vessel invasion and for predicting lymph node metastasis. AIM: To evaluate and compare detection of lymphatic and blood vessel invasion (LVI and BVI) by hematoxylin-eosin (HE) and immunohistochemistry (IHC) in gastric cancer specimens, and to correlate with lymph node status. METHODS: IHC using D2 -40 (a lymphatic endothelial marker) and CD34 (a pan-endothelial marker) was performed to study LVI and BVI in surgical specimens froma consecutive series of 95 primary gastric cancer cases. The results of the IHC study were compared with the detection by HE using the McNemar test and kappa index. The morphologic features of the tumors and the presence of LVI and BVI were related to the presence of lymph node metastasis. A χ2 test was performed to obtain associations between LVI and BVI and other prognostic factors for gastric cancer. RESULTS: The detection rate of LVI was caused higher than that of BVI. The IHC study identified eight false-positive cases and 13 false-negative cases for LVI, and 24 false-positive cases and 10 false-negative cases for BVI. The average Kappa value determined was moderate for LVI (k = 0.50) and low for BVI (k = 0.20). Both LVI and BVI were statistically associated with the presence of lymph node metastasis (HE: P = 0.013, and IHC: P = 0.001, P = 0.019). The mor-phologic features associated with LVI were located in the tumor in the distal third of the stomach (P = 0.039), Borrmann’s macroscopic type Inva-sion (P = 0.03) and the depth of tumor invasion (P = 0.001). The presence of BVI was related only to the depth of tumor invasion (P = 0.003). CONCLUSION: The immunohistochemical identification of lymphatic and blood vessels is useful for increasing the accuracy of the diagnosis of vessel invasion and for predicting lymph node metastasis.