Correlation of MMP12 and hnRNP K expression in NPC biopsy tissues. (A) Immunohistochemical staining of MMP12. A representative NPC biopsy tissue sample containing adjacent nontumor (N) and tumor (T) cells stained with a specific MMP12 antibody is shown at 200x magnification. (B and C) The N and T areas are shown at 400x magnification, respectively. (D-I) Consecutive NPC tissue sections were stained using anti-hnRNP K and anti-MMP12 antibodies, and subjected to immunohistochemical assessment. Representative NPC tissue sections with high-level expression of MMP12 (D and F) and total hnRNP K (E, NHi/C+; G, NHi/C−) and low-level expression of MMP12 (H) and hnRNP K (I, NLo/C−) are shown. TotalHi, total hnRNP K high; TotalLo, total hnRNP K low; NHi, nuclear hnRNP K high; NLo, nuclear hnRNP K low; C+, cytoplasmic hnRNP K positive; C−, cytoplasmic hnRNP K negative; scale bar in (A-C) = 100 μm, (D-I) = 50 μm.