Fig. 1: Study overview, patient imaging, pathology, and single-nuclei profiling.

A Scheme of the pressurized intraperitoneal aerosol chemotherapy (PIPAC) procedure and treatment course for the responder (green) and non-responder (red) patients. Chemotherapy is aerosolized by a nebulizer through a high-pressure injector during laparoscopic surgery under CO₂ capnoperitoneum, allowing better drug distribution and tissue penetration. The responder received six PIPAC cycles; the non-responder discontinued due to progression of disease after two cycles. Created with Biorender.com. B Histologic assessments of peritoneal tumor biopsies taken from multiple abdominal quadrants across treatment cycles. Each colored tile represents whether pathology was positive (tumor present), negative (no tumor), for a given quadrant and cycle. C Contrast-enhanced computed tomography (CT) scans show the clinical response in the responder (left) and the non-responder (right). The baseline CT scans, taken before cycle #1, and the post-treatment CT scans, after cycle #6 for the responder and after cycle #2 for the non-responder, show resolved ascites in the responder (left) compared to progressive hepatic metastasis in the non-responder (right). D Representative hematoxylin and eosin (H&E) staining of tumor samples obtained at various PIPAC cycles. The responder’s biopsies (left panels) show decreased tumor cells and increasing fibrosis by cycle #5, while the non-responder’s samples (right panels) reveal persistent viable tumor at cycles #1 and #2. E Uniform Manifold Approximation and Projection (UMAP) plot of single-nuclei transcriptomic data shows the responder (blue) and non-responder (red). F The UMAP visualization shows the same single-nuclei dataset as in (F), but now colored by assigned cell types: it displays cancer cells, fibroblasts, and T-cells contributing to the tumor microenvironment in each patient sample.