[Clinicopathological significance of SOX2 and FOXG1 expression patterns in ovarian immature teratomas]

Objective: To investigate the relationship between the expression patterns of SOX2 and FOXG1 and the differentiation/development level of neural components in immature teratoma and to determine the clinical significance and potential application of this correlation in a clinical setting. Methods: We conducted a comprehensive whole transcriptome sequencing analysis to identify differentially expressed genes (DEGs) across various subtypes of ovarian germ cell tumors. Additionally, immunohistochemical staining of paraffin-embedded tissue sections was employed to assess the nuclear staining pattern of SOX2 and FOXG1 proteins within the tumor tissues. Results: The transcriptome sequencing data showed that transcription factors SOX2 and FOXG1 exhibited high levels of expression typically in immature teratoma and occupied a pivotal position within the protein-protein interaction network. Immunohistochemical staining revealed the absence of both SOX2 and FOXG1 protein expression in dysgerminoma and yolk sac tumor samples. In immature teratoma, immunohistochemical staining demonstrated diffuse expression of SOX2 and FOXG1 proteins within the inner layer of densely-arranged primitive neuroepithelial tubules. This pattern of expression suggested the presence of stem cell-like properties within these tumor cells. In the sparsely peripheral neurogliocytes, FOXG1 maintained a diffuse nuclear staining pattern resembling that of neuroepithelial cells, while SOX2 exhibited a scattered pattern of positive staining, hinting at a neural lineage differentiation potential. This spatial differential expression pattern of SOX2 and FOXG1 proteins in immature teratoma suggested that primitive neural components within these tumors often recapitulated the trajectory of neural formation and cortical development that was typically observed during embryogenesis. The primitive neural tube acted as the center that constantly moved from inside to outside, with a dynamic shift from the interior to the exterior, paralleled by the sequential differentiation of cell lineages from primitive neuroepithelial stem cells to radial glia, intermediate progenitor cells, and ultimately to precursor glia. Conclusions: This spatial expression pattern of SOX2 and FOXG1 proteins observed in immature teratoma mirrors the lineage differentiation and migration trajectories of primitive neuroepithelial components typically seen in embryonic neurogenesis and cortical development. In daily practice, the combined application of SOX2 and FOXG1 SOX2 and FOXG1 helps identify the primitive neuroepithelial components in immature teratoma, avoid misjudgment of similar morphologies, and thereby assist in the histological grading and clinical decision-making.