Fig 2: PD-L1/PD-L2 and PD-1 status of epithelial cells and cells of the stromal microenvironment, SME (lymphocytes, L; macrophages, M;) from tumor-adjacent normal tissues: (A–F): Expression of PD-L1/PD-L2 and PD-1 by IHC of FFPE sections from epithelial cells of tumor-adjacent normal tissues. The expression of PD-L1/PD-L2 and PD-1 in mesenchymal cells of the stromal microenvironment, SME (lymphocytes, macrophages, and blood vessels) from FFPE sections by IHC is presented. The green square/rectangle is an epithelial cell; the green circle is a lymphocyte (L); the green freeform is a macrophage (M); the green pentagon represents mesenchyme. Insets show images of the selected cells at higher magnifications. Bars represent 20 µM.

Fig 3: Conditional formatting by five-rating icon sets of paired T-TME (A) and N-SME (B) staining for PD-L1, PD-L2, and PD-1 by IHC on FFPE sections from Day0 that were used for sorting by grades 1, 2 and 3 of the disease. A. Conditional formatting of PD-L1, PD-L2, and PD-1 stains by five-rating icon sets of tumor cells (numbers in violet font represent Tumor Proportion Score, TPS (<%) in dark-orange filled rows) and cells of the TME (numbers in green font represent % of positive cells in the TME, including lymphocytes, macrophages, and around blood vessels, in lighter orange rows). Semi-quantification of TILs is represented in the figure. * represents lymphovascular invasion, and ** represents poorly differentiated regions of the tumor. (B). Conditional formatting of PD-L1, PD-L2, and PD-1 stains by five-rating icon sets of tumor-adjacent normal tissues (numbers in blue font represent positive epithelial cells (%) in dark green filled rows) and SME (numbers in black font represent % of positive cells in SME, including lymphocytes, macrophages, and around blood vessels, in lighter green rows).

Fig 4: Diagrammatic presentation of tumor–TME interaction of PD-L1, PD-L2, and PD-1 in endometrial cancers based on the expression pattern of PD-L1, PD-L2, and PD-1. Based on the landscape of PD-L1, PD-L2, and PD-1 expression in the tumor compartment and TME compartment, PD-L1/2-PD-1-mediated immune checkpoint inhibition is proposed. Diagram presenting the expression pattern-based tumor–TME interaction of PD-L1, PD-L2, and PD-1 in endometrial cancers. The tumor-TME interaction based on the IHC expression pattern of PD-L1, PD-L2, and PD-1 in endometrial cancers demonstrated that PD-1-PD-L1/2 immune signaling could be blocked in the tumor stroma following the treatment with immune-checkpoint inhibitors (ICIs). The expression of PD-L1/2 in tumor cells, as well as macrophages and CAFs of the TME, are promising contributors to the inhibition of immune signaling. Pictures represent the expression of PD-L1/PD-L2 and PD-1 of tumor cells and cells of the tumor microenvironment, TME (lymphocytes, macrophages, and cancer-associated fibroblasts designated as TCAF) of FFPE from patients’ tumor tissue samples. The red square is a tumor cell; the red circle is a lymphocyte; the red freeform is a macrophage. The red arrow indicates PD-L1-positive endothelial cells. The dashed arrow represents the possible interaction between PD-L1/PD-L2 with their cognate receptor, PD-1.

Fig 5: PD-L1/PD-L2 and PD-1 status of tumor cells and cells of the tumor microenvironment, TME (lymphocytes, L; macrophages, M; and blood vessels, BV) from tumor tissues: (A): Plan of the study for obtaining PD-L1/PD-L2 and PD-1 status of tumor cells’ tumor-adjacent normal tissue, cells of the tumor microenvironment, TME (lymphocytes, L; macrophages, M; and blood vessels, BV), and cells of the stromal microenvironment, SME, of patients with endometrial cancers. (B–D): Expression of PD-L1/PD-L2 and PD-1 in tumor cells from IHC of FFPE sections. (E–I): Expression of PD-L1/PD-L2 and PD-1 in cells of the TME (lymphocytes, macrophages, and blood vessels) from FFPE of tumor tissues. The red square is a tumor cell; the red circle is a lymphocyte (L); the red arrow is a blood vessel (BV); the red freeform is a macrophage (M). Insets show images of the selected cells at higher magnifications. Bars represent 20 µM.