1. What is tumor microenvironment? 2. Clinical significance in cancers 3. Tumor microenvironment of peritoneal cancer: the concept of premetastatic niche altered before tumor implantation 4. Tumorigenesis and progression of cancer 5. Histopathological features of cancer in peritoneum 6. Metabolism of cancer cells altered in peritoneal tumor microenvironment 7. Cancer stem cells: Dormancy and chemoresistance 8. Immune cells in tumor microenvironment 9. Fibroblasts in tumor microenvironment 10. Cytokine and chemokines in tumor microenvironment 11. Exosomal cell-to-cell interactions in tumor microenvironment 12. Development of diagnostic/prognostic/therapeutic biomarkers 13. Therapeutic approaches targeting tumor microenvironment 14. The concept of xenograft with difference between cancer cell (human) and microenvironment (mice) 15. Tumor organoids model for validation of biomarkers critical for cancer progression 16. Innovative technology to decipher tumoral heterogeneity of peritoneal cancers 17. Tumor evolution during chemotherapy 18. Tumor evolution during metastasis 19. Modulation of tumor microenvironment: (1) Pressure (PIPEC), hydration/temperature (Coelioscopy procedure) and light (photodynamic therapy) 20. Modulation of tumor microenvironment: (2) Surgery 21. Modulation of tumor microenvironment: (3) Radiation 22. Future perspective: Identification and validation of biomarkers using liquid biopsy