Aim: To investigate the expression of receptor-binding cancer antigen expressed on SiSo cells (RCAS1) in metastatic lymph nodes from gastrointestinal cancer.
Methods: Metastatic lymph nodes from gastrointestinal cancer were detected for RCAS1 by immunohistochemical staining and mRNA in situ hybridization.
Results: A total of 102 metastatic lymph nodes from bile duct, gastric, colon and pancreatic cancer were investigated for RCAS1 expression. The immunoreactivity of RCAS1 was identified in 100% of metastatic lymph nodes. Both local and distant metastatic lymph nodes showed RCAS1 expression. On the contrary, specimens of non-cancerous lymph nodes were negative for RCAS1. The result of mRNA in situ hybridization was also confirmed by the finding of immunohistochemical staining. RCAS1 mRNA was detected in all tumor cells that metastasized to lymph nodes.
Conclusion: All metastatic lymph nodes express RCAS1 in tumor cells at both mRNA levels, and RCAS1 that should be used as a complementary factor for identification of metastatic lymph nodes from gastrointestinal cancers.