Background & objective: Immunohistochemical staining is a simple method for determination of lymph node micrometastasis in gastric cancer; but the sensitivity is low. Whether this disadvantage can be improved using multi-antibody combined determination is still controversial. This study was designed to determine the lymph node micrometastasis in patients with gastric cancer by the antibodies of cytokeratin 20 (CK20), epithelial membrane antigen (EMA), and carcinoembryonic antigen 72-4 (CA72-4)for clarifying the value of multi-antibody combined determination of micrometastasis.
Methods: A total of 466 lymph nodes was collected with operation from 44 gastric cancer patients from April 1991 to April 1994. All these lymph nodes showed no lymph node metastasis by routine histological examination. Immunohistochemical staining was performed on all the samples by the mouse antibodies of anti-CK 20, mouse anti-EMA, and mouse anti CA72-4, respectively. Then, the micrometastases were identified under microscope according to the color of the cells. The results were analyzed according to clinical, pathological, and follow-up data.
Results: Fifty-one (10.9%) lymph nodes of 18 (40.9%) cases showed micrometastasis. The number of micrometastatic lymph nodes were detected by CK20, CA72-4, and EMA was 40 (8.6%), 27 (5.8%), and 21 (4.5%), respectively. There was no significant correlation between the lymph node micrometastasis and clinical data, such as gender, age, tumor site, histological differentiation, and stage (P >0.05). The 5-year survival rate of the patients with lymph node micrometastasis was lower than that of the patients without lymph node micrometastasis(61.11+/-11.49% vs. 92.31+/-5.23%, P=0.0113). The 5-year survival rate of the patients with 3 or more positive micrometastatic nodes was lower than that of the patients with less than 3 positive micrometastatic nodes (44.44+/-16.56% vs. 77.78+/-13.86%,P=0.0196).
Conclusion: Immunohistochemical staining marked by different antibodies can be an useful method to seek more micrometastatic lymph nodes in gastric cancer patients.