Published online Oct 15, 2018. doi: 10.4251/wjgo.v10.i10.344
Peer-review started: July 5, 2018
First decision: July 24, 2018
Revised: August 5, 2018
Accepted: August 30, 2018
Article in press: August 31, 2018
Published online: October 15, 2018
To investigate the clinical utility of alpha-fetoprotein (AFP)-producing gastric cancer (AFPGC)-specific microRNA (miRNA) for monitoring and prognostic prediction of patients.
We performed a comprehensive miRNA array-based approach to compare miRNA expression levels between AFP-positive and AFP-negative cells in three patients with primary AFPGC. We next examined the expression levels of the selected miRNAs in five AFPGC and ten non-AFPGC tissue samples by quantitative reverse transcription-polymerase chain reaction to validate their utility. We also investigated the expression levels of the selected miRNA not only in tissue but also in plasma samples. Moreover, we investigated the relationship between plasma AFP levels and plasma selected miRNA expression levels, and also investigated the correlation of the selected miRNA expression levels and malignant potential.
Among the five miRNAs selected from the miRNA array results, the expression levels of miR-122-5p were significantly higher in the AFPGC patients than in the non-AFPGC patients (P < 0.05). In tissue samples, miR-122-5p expression level tended to be lower in the non-AFPGC tissue than the normal gastric mucosa. Conversely, in the AFPGC tissue, miR-122-5p expression level was significantly higher in the AFPGC tissue than both the normal gastric mucosa and the non-AFPGC tissue samples (P < 0.05). Plasma miR-122-5p expression levels were also significantly higher in the AFPGC patients than the health volunteers and the non-AFPGC patients (P < 0.05) and were strongly correlated with plasma AFP levels (r = 0.7975, P < 0.0001). Moreover, the correlation of miR-122-5p expression in tissue samples with malignant potential was stronger than that of plasma AFP level in the AFPGC patients. In contrast, no correlation was found between miR-122-5p expression levels and liver metastasis in the non-AFPGC patients.
miR-122-5p might be a useful biomarker for early detection and disease monitoring in AFPGC.
Core tip: We examined the microRNAs (miRNA) expression in alpha-fetoprotein (AFP)-producing gastric cancer (AFPGC) tissue samples using a comprehensive miRNA array-based approach, and also investigated the clinical utility of the identified AFPGC-specific miRNAs. We found the expression of miR-122-5p was significantly higher in the AFPGC tissues and plasma samples. Moreover, tissue miR-122-5p expression levels exhibited a stronger correlation with malignant potential than plasma AFP level in AFPGC patients. miR-122-5p might be a useful biomarker for early detection and disease monitoring in AFPGC.