Spatial Profiling of Ovarian Clear Cell Carcinoma Reveals Immune-Hot Features

Ovarian clear cell carcinoma (OCCC) has a high incidence in Asia, with a frequent occurrence at an early stage, but without sufficient data on molecular stratification for high-risk patients. Recently, immune-hot features have been proposed as indicators of poor prognosis in early stage OCCC. Specific patterns of intratumoral heterogeneity associated with immune-hot features must be defined. NanoString Digital Spatial Profiling technology (Cold spring biotech corp.) was used to decipher the spatial distribution of the 18-plex protein panel. Regions of interest (ROIs) were collected based on the reference hematoxylin and eosin-stained morphology. Areas of illumination (AOIs) were defined according to the ROI segmentation using the fluorescence signals of the visualization markers pan-cytokeratin (PanCK), CD45, or DNA. Unsupervised hierarchical clustering of 595 AOIs from 407 ROIs showed that the PanCK segments expressed different combinations of immune markers, suggestive of immune mimicry. The following 3 immune-hot clusters were identified: granzyme B-high, immune signal-high , and immune-like cells; the following 2 immune-cold clusters were identified: fibronectin-high and immune checkpoint-high cells. In tumor samples at the International Federation of Gynecology and Obstetrics stage IC1/2 experiencing recurrence, there was an increased occurrence of PanCK+ AOIs with immune signal-high and immune-like cell groups in the papillary morphology surrounded by macrophage lineage tumor-infiltrating immune cells (TIIs). In contrast, for tumor samples at the International Federation of Gynecology and Obstetrics stage IC3/II with recurrence, PanCK+ AOIs were prevalent in the fibronectin-high group, particularly in those with a tubulocystic morphology surrounded by lymphoid lineage non-TIIs. Our study on the spatial profiling of early stage OCCC tumors revealed that the immune mimicry of tumor cells, presence of TIIs, and morphologic patterns were associated with recurrence, which switched during tumor progression.