Further examination of MMP9 via spatial transcriptomics (ST) data from our lab (unpublished) and a previous study34 (Supplementary Fig. S17) revealed that it is specifically enriched in pancreatic intraepithelial neoplasia (PanIN) lesions, which is a histologically well-defined precursor to PAAD, hinting at a potential benign metabolic marker for PAAD. Here, MMP9 is linked to pancreatic adenocarcinoma.