Inclusion Criteria:  Patients diagnosed with peritoneal carcinomatosis (an attempt will be made to cover all histological types of carcinomatosis in similar distribution as 2 patients with carcinomatosis of colonic origin, 2 patients with carcinomatosis of ovarian origin, 2 patients with peritoneal pseudomyxoma, 2 patients with peritoneal mesothelioma and 2 patients with carcinomatosis of gastric origin) with PCI greater than 0 in regions 10-13, and that have been selected as candidates for cytoreductive surgery + HIPEC or for laparoscopy-laparotomy explorer (selection criteria established according to clinical practice usual), and that present peritoneal miliary dissemination consistent with the characteristics of this study for the tissue under examination (implants smaller than 0.25 cm, CC1). Signature of specific informed consent for participation in this study and to obtain biological samples.  Exclusion Criteria:  Patients not suitable for CRS and HIPEC, according to the clinical criteria of the Surgery Unit Oncology and multidisciplinary committee. Refusal of the patient to participate in the study.