Genes or groups of genes may be characterized as differentially expressed in several different ways. For each characterization, finding Those Differentially Expressed Genes is not so hard, given enough computing power. Not so easy is to find physically meaningful characterizations and to provide the assotiated significance measurements. In this talk I will discuss some of the work we have being doing in the analysis of a few Cancer Research related datasets generated in a ongoing collaboration with Ludwig Institute for Cancer Research, Sao Paulo Branch.