Stem Calle

Figure 3-5 Stem-cell niches in various tissues. A, Epidermal stem cells located in the bulge area of the hair follicle serve as a stem cells for the hair follicle and the epidermis. B, Intestinal stem cells are located at the base of a colon crypt, above Paneth cells. C, Liver stem cells (commonly known as oval cells) are located in the canals of Hering (thick arrow), structures that connect bile ductules (thin arrow) with parenchymal hepatocytes (bile duct and Hering canals are stained for cytokeratin 7; D, Corneal stem cells are located in the limbus region, between the conjunctiva and the cornea. courtesy of Tania Roskams, M.D., University of Leuven). (Courtesy of T-T Sun, New York University, New York, NY.) Kumar: Robbins and Cotran: Pathologic Basis of Disease, 7th ed., Copyright © 2005 Saunders

Cell Type	Tissue-Specific Location	Cells or Tissues Produced
Hematopoietic	Bone marrow, peripheral blood	Bone marrow and blood lymphohematopoetic cells
Mesenchymal stem cell	Bone marrow, peripheral blood	Bone, cartilage, tendon, adipose tissue, muscle, marrow stroma, neural cells
Neural stem cells	Ependymal cells, astrocytes (subventricular zone) of the CNS	Neurons, astrocytes, oligodendrocytes
Hepatic stem cells	In or near the terminal bile ductules (canals of Hering)	Oval cells that subsequently generate hepatocytes and ductular cells
Pancreatic Stem cells	Intra-islet Nestin positive cells, oval cells, duct cells	Beta cells
Skeletal muscle Stem cells	Muscle fibers	Skeletal muscle fibers
Stem cells of the skin (keratinocytes)	Basal layer of the epidermis, bulge zone of the hair follicles	Epidermis, hair follicles
Epithelial stem cells of the lung	Tracheal basal and mucus-secreting cells, bronciolar Clara cells, alveolar Type II pneumocyte	Mucous and ciliated cells, type I and II pneumocytes
Stem cells of the intestinal epithelium	Epithelial cells located around the base of each crypt	Paneth’s cells, brush-border enterocytes, mucus secreting goblet cells, enteroendocrine cells

Figure 8-2 Target cells for neoplastic transformation. In many tissues in which cancers arise, the stem cells are the only long-lived cells and are the only cells capable of self-renewal. Because they are already are capable of extensive self-renewal, they are good targets for neoplastic transformation. Dysregulation of the self-renewal process may be simpler in these cells than in progenitor cells that lack this ability. In order for progenitor cells to undergo malignant transformation, they must acquire the ability to undergo extensive self-renewal as a result of oncogenic mutations. Abeloff: Clinical Oncology, 3rd ed., Copyright © 2004 Churchill Livingstone,