Spatial transcriptomic analysis of CLDN6-positive solid and small cluster areas in human ovarian cancer

To investigate the intratumoral heterogeneity of CLDN6 expression in epithelial ovarian cancer (EOC), we performed spatial transcriptomic analysis on clinical specimens. CLDN6-positive cells were observed to form two morphologically distinct patterns: solid tumor areas and dispersed small tumor cell clusters. Using the NanoString GeoMx Digital Spatial Profiler, we compared the gene expression profiles of these two areas within the same tumors. The analysis revealed that small cluster areas showed higher expression of genes related to epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) remodeling compared to solid areas. These findings suggest that morphologically distinct CLDN6-positive areas represent cell populations with different molecular characteristics, highlighting the plasticity of EOC. Overall design: Formalin-fixed, paraffin-embedded (FFPE) tissue sections from two patients with ovarian serous adenocarcinoma were analyzed by spatial transcriptomics using the NanoString GeoMx Digital Spatial Profiler. Regions of interest (ROIs) were selected from CLDN6-positive/Pan-CK-positive areas, categorized as either 'solid tumor areas' or 'dispersed small tumor cell clusters'. Gene expression profiles of Pan-CK-segmented areas within these ROIs were compared to characterize the molecular differences between the two morphological patterns.