• The effect of Cancer Stem Cells on Tumor Growth and Cancer
  • Mehrdad Ostadpoor,1,* Majid Gholami-Ahangaran,2 Seyyed Hossein Heidari,3
    1. Graduated of Veterinary Medicine Faculty, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
    2. Associate Professor, Group of Clinical Sciences, Faculty of Veterinary Medicine, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
    3. Graduated of Veterinary Medicine Faculty, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.


  • Introduction: Cancer stem cells (CSCs) are a small subpopulation of self-renewing malignant and oncogenic cells that drive tumor initiation and progression. CSCs play pivotal roles in tumor initiation, progression, cell death resistance, therapy resistance, and tumor recurrence following treatment and remission. Tumor initiation can either be driven by transformed differentiated cells or transformed tissue resident stem cells. Recent research has identified and isolated cancer stem cells (CSCs), which are considered one of the primary causes of resistance to oncological treatments, and contribute to local and distant recurrence. Studies have shown that stem cells and progenitor cells in normal tissues are susceptible to carcinogenic transformation.
  • Methods: In the current study, keywords including Cancer Stem Cells, Tumor Growth, and Metastasis were reviewed from the list of Mesh and other credible websites including PubMed, Science Direct and Google Scholar and the data was organized. The searches comprised all published papers from 2000 to 2023. All of full text was considered and the papers manifested as only abstract was excluded. The full papers selected that specific effect on cancers only. Totally 50 papers were selected and studied in this review.
  • Results: Recent growing evidence suggest that the tumor is composed of heterogeneous populations of cells with different levels of malignity and the tumor development is driven by a specialized cell subset, characterized by self-renewing, multi-potent, and tumor initiating properties. In colon cancers, recent studies in mice have shown that even differentiated intestinal epithelial cells can be potential CSCs. In squamous cell carcinomas the differentiation phenotype seems to be influenced by the cell of origin and the kind of driver mutation, both responsible for the invasiveness and aggressiveness of the tumor. Tumors generated based on CSCs are believed to follow a unidirectional hierarchy, in which only the CSC population can initiate tumor growth. One article reported the dualistic origin of human tumors, suggesting that tumors could arise from blastomeres generated from fertilized eggs, and stem cells generated from reprogrammed somatic cells. Also, CSCs have been identified in tumors of the liver, pancreas, breast, brain, lung, and ovary. Induction of lung cancer in animal models using genetic modification suggests that lung cancer originates from resident stem cells. Other research demonstrated Mesenchymal stem cells (MSCs) that produce VEGF, Angiopoietin-1 (Ang-1) and other pro-angiogenic factors, could differentiate into pericytes and endothelial cells, which support tumor vascularization and growth.
  • Conclusion: CSCs are capable of generating an entire tumor and tend to be more chemo- and radioresistant due to their quiescent state and upregulation of efflux pumps. CSCs also, can evade the immune system, have efficient DNA damage repair mechanisms, and can easily adapt to hostile environments. Consequently, CSCs have been implicated in tumor recurrence, chemoresistance, metastasis, and thus poor clinical outcomes.
  • Keywords: Cancer Stem Cells, Tumor Growth, and Metastasis