PTEN and neoplasm: To explore this inverse correlation between EZH2 and H3K27me3 expression, we performed immunostaining for the two markers on serial tumour sections from KRAS/Lkb1 adenosquamous tumours, Pten/Lkb1/p53 adenosquamous tumours and Pten/Lkb1 squamous tumours (Fig. 3c).