Representative cases of miRNA expression identified by in situ hybridisation (ISH). ISH analysis revealed characteristic upregulation of miR-223 in the cytoplasm of extranodal NK/T-cell lymphoma, nasal type (EN-NK/T-NT) tumour cells (A1), whereas no signal was detected in peripheral T-cell lymphoma (A2) and inflammatory nasal mucosa (A3). In addition, miR-886-3p was also overexpressed in the cytoplasm of EN-NK/T-NT tumour cells (B1) but was negative in peripheral T-cell lymphoma (B2) and inflammatory nasal mucosa (B3). There were no miR-34c-5p signals in EN-NK/T-NT samples (C1), peripheral T-cell lymphoma samples (C2), or inflammatory nasal mucosa samples (C3). All images show ISH at 400x magnification.