Fig. 2

A2AR is remarkably correlated with HIF-1α, CD73, CD8 and Foxp3 in primary human HNSCC tissues. a Representative immunohistochemical staining pictures of A2AR, HIF-1α, CD73 and Foxp3 in serial primary HNSCC tissue microarray sections were presented at low or high staining intensities (scale bar = 100 μm). b Spearman rank correlation coefficient test and linear tendency test indicated that A2AR was positively correlated with HIF-1α (P < 0.001 r = 0.3862), CD73 (P < 0.001 r = 0.2751) and Foxp3 (P < 0.01 r = 0.2285), but negatively correlated with CD8 (P < 0.05 r = −0.1811)