Geospatial characterization of immune cell distributions and dynamics across the microenvironment in renal cell carcinoma

We performed multiplex immunofluorescence (mIF) using an array of myeloid and lymphoid markers on primary tumor samples from 122 patients with RCC. Regions of interest (ROIs) were selected from three distinct tumor zones: the tumor-core, stroma, and tumor-stroma interface. Digital pathologic imaging analysis was leveraged to quantify the geospatial location and distribution of immune cells within the TIME, and these findings were correlated with a variety of tumor molecular profiles. For patients with ccRCC, as clinical stage increased, immunosuppressive M2-like CD163+ TAMs migrated from the tumor compartment and into the stroma at the tumor-stroma interface and became increasingly co-localized with CD8+ T-cells. Furthermore, high CD163+ TAM clustering into the stromal compartment and high CD8+/CD163+ stromal co-localization were independently associated with worse OS and cancer-specific survival (CSS), while accounting for clinical stage. Overall, this data suggests that the pro-tumor effect of M2-like TAMs and their effect on CD8+ T-cells may be dependent on their specific geospatial location and distribution within the TIME -- namely, that M2-like TAMs exert their pro-tumor effect and interact with CD8+ T-cells most effectively from the stromal compartment at the tumor-stroma interface.