Unreliability of carcinoembryonic antigen (CEA) reverse transcriptase-polymerase chain reaction (RT-PCR) in detecting contaminating breast cancer cells in peripheral blood stem cells due to induction of CEA by growth factors

RT-PCR is increasingly used for the detection of minimal residual disease i n solid tumors, Carcinoembryonic antigen (CEA) RT-PCR seemed to be highly s pecific for detection of tumor cells when tested on PBMC, A very high frequ ency of RT-PCR amplification product for CEA in PBSC from breast cancer pat ients mobilized with G-CSF was found. However, this result contrasted with tumor cell detection by immunocytochemistry (ICC) which showed no correlati on with RT-PCR results. In addition, CEA mRNA was amplified in most G-CSF-m obilized PBSC samples derived from patients with hematological malignancies and from healthy donors of allogeneic stem cells, although no circulating epithelial cells could be demonstrated by ICC, CEA RT-PCR expression was ob served in PBMC from healthy individuals incubated in vitro with G-CSF, Thes e data suggest that CEA transcription can be induced by G-CSF, resulting in a loss of specificity of CEA RT-PCR for tumor cell detection in PBMC, We c onclude, CEA RT-PCR may not be recommended to detect tumor cell contaminati on in peripheral blood from patients treated with G-CSF, This may have impl ications on tumor cell detection by RT-PCR in tissues where endogenous off exogenous growth factors may induce the transcription of CEA or other genes .