Many genes that have been shown to cause cancer were originally identified because of their role in embryonic development and in the postnatal control of cell growth and differentiation. The similarities between cancer and development are evident on many levels. Microscopically, cancerous tissues frequently appear as undifferentiated masses, with some tumor types exhibiting embryonic tissue organization. The increased mobility of cancer cells, leading to local invasion or metastasis, is reminiscent of the migratory behavior of cells during development. We aim to have deeper tumor biology knowledge through gene regulatory network (GRN) models. We consider the characterization of GRNs of tissue specific progenitor/stem cells as a paramount to our understanding of cancerogenesis in colon, lung, and pharynx (CLP) tumor cells. This research proposal underlies the hypothesis that some cancer cells are closely related to progenitor cell of respective tissue, therefore the tumor drug selection should resemble proper stem/progenitor cell differentiation signaling pathway perturbation. We believe that such tumor-customized drug treatment will be more successful, it will shed light on the comprehension of drug effect overall. Moreover it will highlight new aspects of developmental and cancer biology mechanisms. We will use spheroid in vitro model and moreover we will adopt mouse model to validate in vitro data. The predicted outcome of this research is the identification of novel gene regulatory interactions that will be investigated for their roles in carcinogenetic tissues.