BACKGROUND Ameloblastoma (AB) is a common odontogenic epithelial tumor, with 
locally invasive behavior and high recurrence. In this study, we hypothesized 
that miR-524-5p could be involved in the tumor microenvironment by targeting 
interleukin-33 (IL-33)/suppression of tumorigenicity 2 (ST2) in AB. MATERIAL AND 
METHODS The microRNA (miRNA) expression profile of AB tissues and normal oral 
mucosa tissues (NOM; 6 paired samples) was analyzed. The miRNAs with fold change 
≥2 and P<0.05 were considered to be differentially expressed. Among them, 
downregulated miR-524-5p was verified by real-time qPCR. Potential targets of 
miR-524-5p were predicted by bioinformatics analysis. The expression levels of 
target genes were detected using real-time qPCR and Western blot, respectively. 
Immunohistochemistry analysis of target genes was performed, and we also 
assessed the correlation between miR-524-5p and its target. RESULTS Microarray 
analysis results first indicated miR-524-5p is a downregulated miRNA in AB 
tissues. Real-time qPCR results confirmed the expression pattern of miR-524-5p 
in AB tissues. Moreover, IL-33 and its receptor ST2 were significantly 
overexpressed. As shown in immunohistochemistry results, IL-33 was positively 
expressed in lymphocytes and plasma cells, suggesting that IL-33/ST2 
participates in tumor immune responses in the tumor microenvironment. 
Correlation analysis suggested that miR-524-5p expression was negatively 
correlated with IL-33/ST2. CONCLUSIONS Our findings reveal that downregulated 
miR-524-5p can participate in the tumor microenvironment of AB by targeting the 
IL-33/ST2 axis.