This dataset corresponds to a SILAC analysis in mouse xenografts and in cell culture. We analysed signalling in tumors by means of a method based on stable isotope labeling with amino acids of xenograft tumors by the addition of [(13)C(6)]-lysine into mouse food, and also using a typical SILAC analysis in cell culture. This dataset includes 2 groups of analysis: one, with maxquant file tagged SILAX, corresponding to the xenograft analysis, the other one to SILAC analysis in cell culture. Data were acquired on an LTQ-Orbitrap XL mass spectrometer coupled with an Ultimate 3000 HPLC. Analysis was performed using MaxQuant software (version 1.1.1.36). All MS/MS spectra were searched using Andromeda against a database consisting of a combination of Homo sapiens and Mus musculus CPS databases and 250 classical contaminants. Search was performed allowing the following variable modifications: Oxidation (M) and Phospho (STY). FDR was set at 0.01 for peptides and proteins, and the minimal peptide length was six. Quantification was also performed using standard parameters; we considered only proteins with at least two identified/quantified peptides.