We include representative images of patient tumour sections stained with ALDH1A3 and tPA (Fig. 5A), ALDH1A3 and uPA (Fig. 5B), and ALDH1A3 and PAI‐2 (Fig. 5C) and include examples of patient tumour samples that had low and high ALDH1A3 staining. Here, SERPINB2 is linked to neoplasm.