van Baal JOAM, Lok CAR, Jordanova ES, et al. - Integrity of peritoneal elastic lamina (PEL), composition of peritoneal tumor microenvironment (pTME), effects of neoadjuvant chemotherapy (NACT), and their prognostic implications were examined in patients with extensive peritoneal metastases of high-grade serous ovarian cancer (HGSOC). Between 2003 and 2016, peritoneal samples (n = 69) were obtained during cytoreductive surgery. Medical charts were assessed for the clinical data. Residual disease after surgery was more frequently reported for patients with a disrupted PEL compared with those with intact PEL. Increased intraepithelial (ie) CD8+ cells, but no improved survival, was observed in correlation with an intact PEL. Increased ieCD3+ cells were observed after NACT compared with no-NACT. Improved PFS and OS were reported in correlation with increase in CD3+ and CD8+ cells. Findings suggest a possible value of CD3+ and CD8+ cells as prognostic biomarkers.