Cancer is a highly heterogeneous disease with significant cell-to-cell variability. Therefore, understanding the sources of this heterogeneity might help to design new therapies. Akt is a therapeutic target for cancer treatment and it is known to be regulated through numerous posttranslational modifications (PTMs) as well as to be recruited to different subcellular compartments. However, little is known about how a cell determines which substrates and functions Akt should regulate. Our hypothesis is that the Akt molecular code, i.e. the profile of PTMs of Akt, can determine its subcellular localization and vice versa, thus establishing the subset of Akt substrates and functions that Akt displays after each stimulus/cellular context. The aim of this study is to determine modification and subcellular localization patterns of Akt and its substrates in different mammary cell lines, both normal and tumor, and to analyze if a correlation between these variables and the resistance/sensitivity of these cell lines to antitumor drugs can be established. Using a strategy that combines automated imaging and quantitative measurement of Akt localization, we discovered novel Akt modifications and localizations. Preliminary results show that phosphorylation and localization patterns of Akt and its substrates differ between normal and tumor mammary cell lines. A bioinformatic study was performed to analyze association of Akt substrates grouped by cell compartment and different types of neoplasms.