Association between low expression levels of interleukin-9 and colon cancer progression

Although interleukin (IL)-9 has been extensively studied in inflammation and autoimmune diseases, the expression level of IL9 in colon cancer and its clinical significance are less well established. In total, 15 healthy donors (HDs) and 60 patients who had been diagnosed with colon cancer that had undergone a surgical resection were enrolled in the study. The plasma levels of IL9 in the HDs and cancer patients were detected by the liquid chip technique, while the expression levels of IL9 in the colon cancer tissues and normal tissues were analyzed using immunohistochemistry (IHC) and reverse transcriptionquantitative polymerase chain reaction (RTqPCR). Finally, the difference in the expression levels of IL9 between the patients classified as tumornodemetastasis stage  and stage  was compared. The results demonstrated that the plasma levels of IL9 in the patients with colon cancer were significantly lower when compared with the HDs (1.29 vs. 2.53 pg/ml, P<0.05). Furthermore, according to the IHC and RTqPCR results, low expression levels of IL9 were observed in the colon cancer tissues when compared with the normal tissues (P<0.05). With regard to the plasma and tumor tissue samples, patients diagnosed with stage  colon cancer expressed lower levels of IL9 compared with the stage  patients (P<0.05). In conclusion, low expression levels of IL9 were observed in the tissue and plasma samples collected from the colon cancer patients, and the decreased expression of IL-9 was shown to correlate with colon cancer progression.