Tumor associated macrophages (TAMs) are an important element of tumor stroma. They originate from blood monocytes attracted by chemokines and cytokines produced by tumor cells and, being instructed by tumor microenvironment, develop into potent tumor-supporting cell population. TAMs were demonstrated to directly stimulate tumor cell proliferation and to promote angiogenesis. Further TAMs provide for efficient immune escape by producing immunosuppressive cytokines and facilitate tumor dissemination by producing extracellular matrix remodeling enzymes. In renal cell carcinoma (RCC), numerous studies were performed for elucidation of the role of TAM in tumor progression. Using pan-macrophages marker CD68 and type 2 macrophage (M2) markers CD163 and CD206, it was demonstrated that increased density of TAMs is associated with poor survival of patients. Although most of the studies are focused on M2 population in RCC, several markers rather typical for type 1 macrophages (M1) were also characterized. Macrophages isolated from RCC tumors were shown to produce proinflammatory cytokines TNFα, IL-1β, IL-6, and CCL2. It can be concluded that RCC is an excellent example of a tumor with hybrid phenotype of TAMs that share both M1 and M2 properties. Moreover, TAMs seem to be an attractive therapeutic target as well. Further investigations are needed for identification of RCC-specific TAM markers with high predictive capacity and/or suitable for therapeutic targeting.

The link between a lung tumor and the lung microbiome is a largely unexplored issue. To investigate the relationship between a lung microbiome and the phenotype of an inflammatory stromal infiltrate, we studied a cohort of 89 patients with non-small cell lung cancer. The microbiome was analyzed in tumor and adjacent normal tissue by 16S rRNA amplicon sequencing. Characterization of the tumor stroma was done using immunohistochemistry. We demonstrated that the bacterial load was higher in adjacent normal tissue than in a tumor (p = 0.0325) with similar patterns of taxonomic structure and alpha diversity. Lung adenocarcinomas did not differ in their alpha diversity from squamous cell carcinomas, although the content of Gram-positive bacteria increased significantly in the adenocarcinoma group (p = 0.0419). An analysis of an inflammatory infiltrate of tumor stroma showed a correlation of CD68, iNOS and FOXP3 with a histological type of tumor. For the first time we showed that high bacterial load in the tumor combined with increased iNOS expression is a favorable prognostic factor (HR = 0.1824; p = 0.0123), while high bacterial load combined with the increased number of FOXP3+ cells is a marker of poor prognosis (HR = 4.651; p = 0.0116). Thus, we established that bacterial load of the tumor has an opposite prognostic value depending on the status of local antitumor immunity.

Esophageal cancer is one of the most aggressive malignant neoplasms, with low survival rates and limited treatment options. In this study we analyzed the microbiome composition and the phenotype of inflammatory tumor infiltrate in squamous cell carcinoma of esophagus (ESCC) and examined possible relationships between them and their prognostic significance. We found that the predominant phyla of microorganisms found in both tumors and adjacent normal tissues were Firmicutes, Proteobacteria, Actinobacteria, Gemmatimonadetes and Bacteroidetes. We established that only bacteria of the genus Staphylococcus differ between tumors and normal tissues. We found a significant correlation between bacterial burden and the phenotype of the tumor stroma. Namely, a group of tumors characterized by a high expression of CD206 (r = −0.3976, p = 0.0056) in the stroma and iNOS (r = −0.2953, p = 0.0439) in tumor cells is characterized by a higher bacterial burden. Further, we established that in the group with a high content of CD206+ macrophages, there is also a predominance of gram-positive bacteria over gram-negative ones. We found that gram-positive bacterial burden is associated with disease prognosis in ESCC showing high content of CD206+ macrophages. In conclusion we established that the tumor microbiome, can be prognostically significant for ESCC when combined with other stromal markers.

There is an urgent need for identification of new prognostic markers and therapeutic targets for non-small cell lung cancer (NSCLC). In this study, we evaluated immune cells markers in 100 NSCLC specimens. Immunohistochemical analysis revealed no prognostic value for the markers studied, except CD163 and CD206. At the same time, macrophage markers iNOS and CHID1 were found to be expressed in tumor cells and associated with prognosis. We showed that high iNOS expression is a marker of favorable prognosis for squamous cell lung carcinoma (SCC), and NSCLC in general. Similarly, high CHID1 expression is a marker of good prognosis in adenocarcinoma and in NSCLC in general. Analysis of prognostic significance of a high CHID1/iNOS expression combination showed favorable prognosis with 20 months overall survival of patients from the low CHID1/iNOS expression group. For the first time, we demonstrated that CHID1 can be expressed by NSCLC cells and its high expression is a marker of good prognosis for adenocarcinoma and NSCLC in general. At the same time, high expression of iNOS in tumor cells is a marker of good prognosis in SCC. When used in combination, CHID1 and iNOS show a very good prognostic capacity for NSCLC. We suggest that in the case of lung cancer, tumor-associated macrophages are likely ineffective as a therapeutic target. At the same time, macrophage markers expressed by tumor cells may be considered as targets for anti-tumor therapy or, as in the case of CHID1, as potential anti-tumor agents.