Fibroblasts and the secreted structural proteins including collagen, fibronectin, elastin, vitronectin, etc. comprise the intraperitoneal sub-mesothelial matrix. Fibroblasts are the main regulator of ECM in physiological situations [
74]. Transformation of peritoneal fibroblasts into cancer-associated fibroblasts (CAFs) is one of the important causes of peritoneal metastasis of ovarian cancer. Currently, the source of intra-abdominal CAFs is not clear. The traditional belief is that peritoneal CAFs are derived from peritoneal resident cells, that is, the transformation of peritoneal resident cells into CAFs upon stimulation by tumor cells [
82] while the new theory proposes that the CAFs are originated from mesothelial cells, that is, mesothelial cells undergo MMT with spindle changes, decreased expression of epithelial markers such as E-cadherin and increased expression of mesenchymal markers such as α-smooth muscle actin(αSMA) [
83,
84]. Cytokines including IL-6, TGF-β could drive tumor-associated CAF phenotype and promote tumor metastasis [
85,
86]. CAFs facilitate ovarian cancer progression through direct or indirect effects. As previously described, ECM deposition including collagen crosslinking plays a significant role in OC progression [
73]. Studies demonstrate that CAFs assist OC progression through regulating ECM and a desmoplastic reaction [
74]. Besides, CAFs secrete cytokines and promote peritoneal metastasis of OC [
87,
88]. For example, fibroblasts could secrete TGF-β2, which can promote levels of CXCL12, IL-6 and VEGF-A, inducing immune evasion of cancer cells and angiogenesis [
89]. TGF-β signal pathway associated molecules such as versican (VCAN) could also promote CAFs phenotypic transformation by activating the TGF-β pathway, resulting in tumor metastasis [
90]. In addition, CAFs promote peritoneal metastasis by metabolic reprogramming of tumor cells. For instance, the nutrient-deficient hypoxic peritoneal microenvironment activates mitophagy and autophagy of CAFs, which provides substrates such as lactate for mitochondrial oxidative phosphorylation metabolic pathways in adjacent tumor cells, contributing to OC progression [
91]. Moreover, CAFs secrete VEGF and promote tumor angiogenesis, contributing tumor progression [
92].