On the other hand, in the present study, hybridoma cells were first screened for murine IgG production by ELISA, since it is possible that mAbs suitable for immunostaining of denatured human tumor CD26 in FFPE cell block and tissue specimens would not react well to native (undenatured) CD26 or urea-treated CD26 protein, as analyzed by flow cytometry or ELISA. The gene discussed is DPP4; the disease is neoplasm.