Gene expression of SOX2 , NANOG and OCT4 in different tumor samples shows clustering of embryonic factors in certain tumors. Real-time PCR for SOX2, NANOG and OCT4 was performed on isolated RNA from tumor tissue. RNA from undifferentiated human pluripotent stem cells was used as a control. Shown are fold relative gene expression levels in comparison to undifferentiated pluripotent stem cells. Experiments have been performed in triplicates: error bars depict standard deviations.