Single-cell RNA sequencing reveals tissue architecture in small cell carcinoma of the ovary, hypercalcemic type

Background and purpose: Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is a highly malignant, extremely rare primary undifferentiated ovarian cancer. This study aimed to reveal the tumor microenvironment and cellular and molecular characteristics of SCCOHT, and to explore potential drug targets. Methods: We collected recurrent pelvic lesions from one patient with SCCOHT, and applied single-cell RNA sequencing (scRNA-seq) to explore key cell subsets and potential drug targets. We further verified them at the cytological level. Results: There were four cell subsets and twelve cell subclusters of induced pluripotent stem cell (iPSC), neural Schwann cells, neuroepithelial cells and macrophages in the recurrent lesions of SCCOHT. The expression of genes significantly up-regulated by iPSC cell subgroups were mainly concentrated in cell cycle regulation, among which PLK1 was the most significantly up-regulated gene. PLK1 protein was positively expressed in SCCOHT tissue sections and increased in SCCOHT cell lines. Conclusion: It was revealed that the tumor microenvironment of SCCOHT was composed of iPSCs, neural Schwann cells, neuroepithelial cells and macrophages. The key cell subsets of iPSCs were identified, and PLK1 gene was found as a potential therapeutic target.