Inverse relationship between ETV7 and SERPINE1 in OSCC. (A) Representative immunostaining for ETV7 (red) in SJG26 and SJG6 tumour biopsies with DAPI counterstain (blue). Scale bar: 200 μm. (B) Quantification of mean nuclear ETV7 staining in OSCC tumour biopsies. Note lower % ETV7 positive cells in NOTCH1 mutant tumour (SJG6) compared to NOTCH1 wild type (SJG26). Multiple t-test, *p < 0.05. (C) Representative immunostaining for SERPINE1 (green) in SJG26 and SJG6 tumour biopsies with DAPI counterstain (blue). Scale bar: 200 μm. (D) Quantification of staining intensities for NOTCH1, ETV7 and SERPINE1 in SJG6 (NOTCH1 mutant) and SJG26 (NOTCH1 WT) tumour biopsies. One sample t-test was used. *p < 0.05; **p < 0.01; ****p < 0.0001. (E) Schematic of the NOTCH1/ETV7/SERPINE1 regulatory axis. (B, D) Data represent mean ± SD.