Figure 6

Correlation of the expression of PRDM1 and miR-223 in extranodal NK/T-cell lymphoma, nasal type (EN-NK/T-NT). (A) The expression of PRDM1 and miR-223 in EN-NK/T-NT cases were analysed by immunohistochemistry (IHC) and in situ hybridisation (ISH), respectively, and the result is shown as a scatter diagram. As described in the Materials and Methods section, these results were semi-quantitatively scored into 3 grades according to the number of positive tumour cells. In this figure, the numbers of ordinate are as follows: “1” indicates negative (0% to <10% positive cells), “2” indicates weak (10% to ≤50% positive cells), and “3” indicates strong (>50% to 100% positive cells). Statistically, a significantly opposing correlation was observed between the levels of PRDM1 protein and miR-223 expression in 31 EN-NK/T-NT cases (P < 0.001); only 2 cases had the same relative expression levels of PRDM1 and miR-223. (B) One representative case of EN-NK/T-NT was negative for PRDM1 by IHC but strongly positive for miR-223 by ISH (400×). (C) qRT-PCR analysis revealed much lower levels of miR-223 in YT cells than in NK92, NKL, and K562 cells (mean ± SE of 3 independent experiments). (D) Western blotting revealed markedly higher levels of PRDM1α protein in YT cells than in NK92, NKL, and K562 cells.