Differential expression of miR-21 and miR-75 in esophageal carcinoma patients and its clinical implication

In Xinjiang, China, esophageal carcinoma has a high incidence in Kazak and Uighur populations. MicroRNA (miR)-21 and miR-375 are related to esophageal carcinoma. This study thus investigated their potencials in early diagnosis and prognosis in Kazak and Uighur populations, to provide evidences for serum markers of esophageal cancer. A total of 126 Kazak or Uighur esophageal cancer patients were enrolled as the disease group, along with 86 local Han patients as disease control cohort, and 80 healthy Kazak or Uighur individuals. MiRNA expression was detected by in situ hybridization in tissues and by qRT-PCR in serum. ROC approach was used to evaluate the diagnostic value of miRNA on esophageal carcinoma. Cox analysis was performed to screen factors governing prognosis. MiR-21 level was significantly elevated in both tissue and serum samples of esophageal cancer patients, while miR-375 was down-regulated. Such difference was more potent in disease group compared to disease control group. MiR expression was correlated with infiltration depth, TNM stage, vascular invasion, and lymph node metastasis. Elevated expression of miR-21 reduced the sensitivity of radio-therapy, and increased recurrence frequency. The diagnostic value of single assay for miR-21 or miR-375 was lower than the combined assay (AUC=0.812 or 0.739 vs. 0.858). They also affected patient prognosis (OR=1.53 or 0.652). MiR-21 and miR-375 presented abnormal expression in Kazak or Uighur esophageal carcinoma patients and were independent factors affecting prognosis. The combined assay of miR-21 and miR-375 may help to make early diagnosis of esophageal cancer.