[Expression of miRNA let-7a and HMGA2 and Diagnostic Value of Serum miRNA let-7a Level in Pancreatic Cancer].

Objective: To investigate the diagnostic value of miRNA let-7a, high mobility group A2 (HMGA2) expression and serum miRNA let-7a level in pancreatic cancer.
Methods: From January 2014 to January 2019, 60 patients with pancreatic cancer were collected for fresh pancreatic ductal adenocarcinoma tissue and normal pancreatic tissue adjacent to the cancer after the operation. Serum samples before and after operation were also collected, while 60 healthy people were enrolled as the control group. The expression of miRNA let-7a (qRT-PCR) and HMGA2 (qRT-PCR and Western blot) in cancer and adjacent normal tissues were measured. The serum level of miRNA let-7a was detected by qRT-PCR. The relationship between miRNA let-7a and HMGA2 expression and the clinicopathological features of pancreatic cancer was analyzed. The diagnostic value of serum miRNA let-7a pre-operation in patients with pancreatic cancer was also analyzed with ROC curve.
Results: Compared with normal tissues adjacent to the cancer, the expression level of miRNA let-7a in pancreatic cancer tissues decreased ( t =20.291, P <0.01), and the expression of HMGA 2 mRNA increased ( t =46.681, P <0.01). The expression of HMGA2 protein in cancer tissues was higher than that in normal tissues adjacent to the cancer ( t =22.973, P <0.01). The serum level of miRNA let-7a in pancreatic cancer patients was significantly lower than that in healthy controls ( t =24.854, P <0.01). The relative level of serum miRNA let-7a at 1 week after surgery was significantly lower than that before surgery in pancreatic cancer patients ( t =6.885, P <0.01). There was a positive correlation between cancer tissue and serum miRNA let-7a expression 1 week after surgery ( r =0.411, P =0.000). The relative expression levels of miRNA let-7a and HMGA2 in pancreatic cancer tissues were significantly different in different TNM stages and lymph node metastasis ( P <0.05). The area under curve of pre-operation serum miRNA let-7a for the diagnosis of pancreatic cancer was 0.823 ( 95% confidence interval: 0.665-0.917); when the optimal cut-off value of miRNA let-7a was 0.614, the sensitivity was 82.3%, the specificity was 74.1%.
Conclusion: The expression of HMGA2 may be involved in the invasion and metastasis of pancreatic cancer. The level of serum miRNA let-7a may provide a reference for the diagnosis and postoperative monitoring of pancreatic cancer.
(Copyright© by Editorial Board of Journal of Sichuan University (Medical Science Edition).)