This study investigates the association between microRNA (miRNA) expression profiles and prognosis, as well as therapeutic outcomes in colon adenocarcinoma. Researchers analyzed miRNA expression in tumor and paired non-tumor tissues from 84 patients in the United States and 113 patients in Hong Kong. They identified 37 miRNAs that were differentially expressed in tumors, with miR-21, miR-20a, miR-106a, miR-181b, and miR-203 showing significant associations with poor survival and therapeutic outcomes. miR-21 was particularly associated with poor survival in both cohorts, independent of clinical factors such as TNM staging. High miR-21 expression was also linked to a poor response to adjuvant chemotherapy. In situ hybridization confirmed that miR-21 was highly expressed in colon carcinoma cells. The study found that miR-21 expression levels were higher in more advanced tumors and in adenomas. These findings suggest that miR-21 may serve as a prognostic biomarker and therapeutic target for colon adenocarcinoma. The study highlights the potential of miRNAs as diagnostic and therapeutic tools in cancer, emphasizing their role in tumor progression and response to treatment. The results indicate that miR-21 expression could be a useful indicator for predicting patient outcomes and guiding treatment strategies in colon cancer.This study investigates the association between microRNA (miRNA) expression profiles and prognosis, as well as therapeutic outcomes in colon adenocarcinoma. Researchers analyzed miRNA expression in tumor and paired non-tumor tissues from 84 patients in the United States and 113 patients in Hong Kong. They identified 37 miRNAs that were differentially expressed in tumors, with miR-21, miR-20a, miR-106a, miR-181b, and miR-203 showing significant associations with poor survival and therapeutic outcomes. miR-21 was particularly associated with poor survival in both cohorts, independent of clinical factors such as TNM staging. High miR-21 expression was also linked to a poor response to adjuvant chemotherapy. In situ hybridization confirmed that miR-21 was highly expressed in colon carcinoma cells. The study found that miR-21 expression levels were higher in more advanced tumors and in adenomas. These findings suggest that miR-21 may serve as a prognostic biomarker and therapeutic target for colon adenocarcinoma. The study highlights the potential of miRNAs as diagnostic and therapeutic tools in cancer, emphasizing their role in tumor progression and response to treatment. The results indicate that miR-21 expression could be a useful indicator for predicting patient outcomes and guiding treatment strategies in colon cancer.