Using a combination system of Transcription and PCR, we examined gene expression of TNF-alpha, TNF-beta and other cytokines (IL-1, G-CSF, IL-3 and IFN-gamma) in embryonal carcinoma cell lines (PCC3, PCC4, ECA2 and F9) and trophoblast cell line (PL/B6). We found that both TNF-alpha and TNF-beta transcripts were expressed in all of the embryonic cell lines. We also detected transcripts of two types of TNF receptors and transcription factor NF-kappa B in these embryonic cells.