Stem cells are undifferentiated cells and play a critical role in tissue development, homeostasis, and regeneration. Stem cells self-renewal divisions are controlled by intrinsic and extrinsic factors. Failure of stem cells function in tissue maintenance results in degenerative diseases, on the other hand, the overproliferation of stem cells results in tumor development (Singh et al., Cell Research, 2005; Singh et al., Oncogene, 2006; Singh et al., Cell Stem Cell, 2007; Singh et al., Journal of Cellular and Molecular Medicine, 2011; Singh, Current Medicinal Chemistry, 2012; Singh, Cancer Letters, 2013; Singh et al., Nature, 2016; Singh et al. Nature Communications, 2016; Singh et al., Advances in Experimental Medicine and Biology, 2019). Our current research is directed toward understanding the molecular genetic mechanisms by which stem cells regulate tissue homeostasis, regeneration, (Obara et al., Scientific Reports, 2019) and tumorigenesis. We are utilizing model organisms and various tissues and cell systems to understand the above mechanisms. We are also involved in cancer drug screening to identify novel regulators of regeneration, and cancer therapy (Choi et al., Cancer Letters, 2019), and exploring the role of tumor-targeting bacteria for cancer therapy (Igarashi et al., Translational Oncology, 2020).