AIM: To investigate the in situ expression of suppression of tumorigenecity 13 (ST13) mRNA in both colorectal cancer and adjacent normal tissues, METHODS: Colorectal cancer cell lines SW1116, SW620 and CoLo205 were enrolled to confirm the feasibility of the in situ hybridization procedure. Seven colorectal cancer and adjacent normal tissues were included for RNA-RNA in situ hybridization. RESULTS: The expression of ST13 in the seven normal colon tissues was positive and the positive signals appeared in mucosal cells. Only three of the seven colorectal cancer tissues had positive hybridization signals that appeared in adenocarcinoma cells. CONCLUSION: The expression of ST13 decreases in colorectal cancer tissue compared with that in adjacent normal tissue. ST13 is mostly expressed in colorectal epithelia and adenocarcinoma cells. AIM: To investigate the in situ expression of suppression of tumorigenecity 13 (ST13) mRNA in both colorectal cancer and adjacent normal tissues, METHODS: Colorectal cancer cell lines SW1116, SW620 and CoLo205 were enrolled to confirm the feasibility of the in situ hybridization procedure. Seven colorectal cancer and adjacent normal tissues were included for RNA-RNA in situ hybridization. RESULTS: The expression of ST13 in the seven normal colon tissues was positive and the positive signals appeared in mucosal cells. Only three of the seven colorectal cancer tissues had positive Hybridization signals that had been in adenocarcinoma cells. CONCLUSION: The expression of ST13 decreases in colorectal cancer tissue compared with that in adjacent normal tissue. ST13 is mostly expressed in colorectal epithelia and adenocarcinoma cells.