GNRH1 and colon carcinoma: In this paper, the synthesis and the analytical characterization of the above-mentioned GnRH conjugates with or without 4Lys(Bu) were described, while their antiproliferative and apoptotic activity were studied by impedimetry (xCELLigence SP System), flow cytometry and quantitative real-time RT-PCR in HT-29 human colon carcinoma cell line.