PDPN and neoplasm: Tumor cell positivity for PDPN immunoreactivity was significantly more frequent in EMPM (11/11, 100%) than in LAC (2/100, 2%; p < 0.0001) or LSCC (10/23, 43.5%; p = 0.0018) (Figure 2a,b: representative immunohistochemical results; Figure 2c: bar graph).