Serum miR-1301-3p, miR-335-5p, miR-28-5p, and their target B7-H3 may serve as novel biomarkers for colorectal cancer.

Purpose: B7-H3, a member of the B7 family of immune regulatory ligands, plays a critical role in the T cell-mediated immune response. It is broadly expressed in several human cancers and leads to poor prognosis. Nevertheless, the clinical significance of B7-H3 expression in colorectal cancer (CRC) remains unclear.
Methods: The serum B7-H3, B7-H1, cancer-associated carbohydrate antigen-50 (CA-50) and carcinoembryonic antigen (CEA) expressions in patients with CRC, benign gastrointestinal diseases, and healthy controls were measured by ELISA. The miRNAs that target B7-H3 were predicted by using the miRTarBase. Real-time PCR was performed to examine their expressions in patients with CRC.
Results: B7-H3, B7-H1, and CA-50 expressions were higher in patients with CRC than those in healthy controls and the patients with benign gastrointestinal diseases. B7-H3 expression was correlated with TNM stage and metastasis. It was predicted that B7-H3 was a target of miR-1301-3p, miR-335-5p, and miR-28-5p and its expression was negatively related to these three miRNAs expressions. Serum miR-1301-3p, miR-335-5p, and miR-28-5p expressions were also correlated with the TNM stage and metastasis.
Conclusion: Our results indicated that serum miR-1301-3p, miR-28-5p, miR-335-5p, and B7-H3 expressions were correlated with pathological stages of CRC and metastasis and may therefore serve as novel biomarkers for CRC diagnosis and treatment.