Aberrant Expression of miR-203 and Its Clinical Significance in Gastric and Colorectal Cancers

Background MicroRNAs (miRNAs) are small, non-coding RNAs of endogenous origin, they have been increasingly shown to have aberrant expression in many tumor types. miR-203 has not been comprehensively investigated in gastric and colorectal cancers. Methods Total RNA was extracted from tissues of 212 patients with gastric or colorectal cancer as well as from seven gastric and colorectal cell lines. We determined the expression of miR-203 by real-time PCR and calculated using the 2-(Delta Delta Ct) method. Then, we assessed miR-203 expression and clinicopathologic characteristics. Finally, we studied the effect of miR-203 on cell proliferation in SGC-7901 cells by MTT. Results miR-203 has significantly low expression in colorectal cancer tissues (p < 0.001, paired t test) and cancer cell lines compared to non-tumor counterparts. Moreover, low expression of miR-203 was correlated with tumor size (p = 0.015, non-parametric test) and pT stage (p = 0.005) in colorectal cancer. Although expression of miR-203 was not significant in gastric cancer tissues (p = 0.124), interestingly, miR-203 was correlated with tumor size (p = 0.023), macroscopic type (p = 0.045), and pT stage (p = 0.013). Furthermore, we found miR-203 can inhibit the cell proliferation in SGC-7901 cells. Conclusion miR-203 may be related to the proliferation and invasion of gastric and colorectal cancers.