Background: Ovarian teratomas are predominantly benign tumors, derived from germ cells and may contain tissue originating from all three embryonic germ layers: endoderm, mesoderm and ectoderm. Some of the tissue derivatives are highly developed and include hair and neuronal tissues. However, the presence of immature neuroepithelium is used as a diagnostic marker for malignant potential. Similarly, the expression of pluripotency and early neuronal markers has been reported to correlate with ovarian cancer grade in humans.[1] The trigger of ovarian teratoma development is described as parthenogenic, where an unknown error in normal development results in auto-activation of the germ cell and subsequent embryonic-like development. These tumors may therefore, provide a unique model for studying mechanisms regulating germ cell and embryonic development. The aim of this preliminary study is to investigate ovarian teratomas as a model for the regulation of early development using a commercially available mouse strain exhibiting ovarian teratomas in approximately 50% of females.[2] 

Method: Ovarian and control tissue from 10 mice was provided from the LT/SvEiJ strain in RNAlater. Tissues were processed to provide RNA for gene expression analysis, DNA for epigenetic analysis, or FFPE sections for histochemistry staining. Analyses targeted neural stem cell differentiation markers (Oct4, Pax6, Nes, Gfap, DCX, NeuN and Olig2), as well as Homeobox genes associated with dorso-ventral axis embryonic development and not/poorly expressed in adult tissue[3] (HoxB1, HoxB4, HoxA7, HoxA10, HoxA11 and Hox C13).
Results: Preliminary analysis indicates that this subset of neuronal differentiation markers and embryonic axis markers are differentially expressed in the ovarian teratomas of the mouse model.
Discussion: This mouse model has the potential to provide useful insights into (dys-)regulation of oocyte and embryonic development. The application of this research to human teratomas may provide a model for oocyte and embryonic development that is more accessible and less controversial than using human oocytes and embryos.

1. Abiko K, et al. Am J SurPath 2010;34(12):1842-48.
2. Eppig JJ, Wigglesworth K, Hirao Y. Developmental Biology 2000;224(1):60-68.
3. Takahashi Y, Hamada J-i, Murakawa K, Takada M, Tada M, Nogami I, et al. Experimental Cell Research 2004;293(1):144-53.