Mucinous ovarian carcinoma (MOC) is among the less common histotypes of ovarian cancer whose prevention and treatment could be positively impacted by the correctly identifying its tissue of origin and its cellular composition.
Historically, all epithelial ovarian cancer histotypes were classified morphologically into tumours and they were all thought to arise directly or indirectly from the Ovarian Surface Epithelium (OSE). Although analysis of the gene expression profile of MOC has not lead to a consensus on MOC origin, it is clear that its expression profile is distict from other subtypes and normal gynaecological tissues. Moreover, there have been studies that considered non-ovarian origins for MOC. Therefore, the origin and nature of MOC still remains debatable.
To better understand MOC and its distinction among ovarian cancer subtypes at single cell resolution we performed Single Cell Multiome ATAC + Gene Expression analysis on MOC. ScRNA-seq gene expression data were integrated with chromatin accessibility data for each cell. Differentially accessible peaks and genes between cell types were calculated. Next, we used complementary methods to find motifs with differential activities between cells. Finally, publicly available scRNA-seq datasets on serous cancers were used to compare the tumour cell type compositions.
We annotated the cellular components of MOC and provided cell-type specific markers for these cell types. Furthermore, cellular motif activity and enriched transcription factors were described for MOC. Our work can help understand this rare ovarian tumour subtype and have a positive impact on prevention and treatment of this cancer.