Preliminary Exploration of the Relationship between Tumor Microenvironment in Malignant Ascites and Patient Prognosis

Malignant ascites (MA) is a common complication of tumors which related to poor prognosis. With the deepening of the research on tumor microenvironment (TME), the influence of TME on prognosis is gradually understood. As a special TME, the relationship between MA and prognosis of patients need to be explored. 39 samples of MA in West China Hospital from 2018 to 2022 were collected for immunohistochemical (IHC) staining of CD4, CD8, CD11b, CD11c, CD16, CD19, CD163 and FOXP3. Through analyzing the relationship between the proportion of positive cells and the ascites-specific survival (ASS) of patients, immune cells infiltration score (ICIS) related to immune cell infiltration was established. Based on Kruskal-Wallis H test, the expression of CD8 in MA of different tumor types was significantly different ( P  = 0.014), the proportion of CD8 positive cells in biliary tract tumors is significantly higher than that in gastrointestinal (GI) tract tumors ( P  = 0.032). According to the multivariate cox regression analysis, only whether to receive chemotherapy was an independent prognostic risk factor. ICIS 1 (CD4, CD8, CD163, FOXP3) and ICIS2 (CD4, CD8, CD11b, CD11c, CD16, CD19, CD163, FOXP3) constructed according to immune cell infiltration can effectively predict the ASS of patients (ICIS1: High expression vs low expression, HR, 0.43, 95%CI (0.22–0.84), P  = 0.0065; ICIS2: high vs. low expression, HR, 0.36, 95%CI (0.16–0.79), P  = 0.0007). In general, the immune cells in MA are related to the survival of patients. The distribution model of immune cells based on TME has a good predictive value for the survival of patients.