The spontaneous release of a glyconucleoprotein complex in the supernatant of eukaryote cell cultures is a general phenomenon independent of cell lysis. The DNA recovered from this glyconucleoprotein material contains most part of the genome. The SW 480 cell line, originating from a human colon carcinoma, presents a point mutation of the K-ras gene on both alleles. These cells in culture release the mutated K-ras gene. When crude SW 480 cell supernatant is given, without any other adjonction, to NIH/3T3 mouse cells, transformed foci appear as numerous as those occurring after a transfection provoked by a cloned E.J. ras gene administered as a calcium precipitate. The presence of a mutated ras gene in the transfected foci of the 3T3 cells has been checked by hybridization, after PCR, with an oligonucleotide probe specific to the mutation. This result was confirmed by sequencing the PCR product.