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Am J Transl Res 2013;5(6):563-581
Review Article
CD133: to be or not to be, is this the real question?
Elena Irollo, Giuseppe Pirozzi
Department of Experimental Oncology, Istituto Nazionale Tumori Fondazione G. Pascale, Naples, Italy
Received August 7, 2013; Accepted August 31, 2013; Epub September 25, 2013; Published September 30, 2013
Abstract: CD133 (prominin-1) is a member of the transmembrane glycoprotein family and was initially described
as a specific marker to select human hematopoietic progenitor cells. Later it was recognised as an important
marker to identify and isolate the specific cell subpopulation termed “cancer stem cells” (CSCs). Many studies
showed that CD133+ cells have stemness properties such as self-renewal, differentiation ability, high
proliferation and they are also able to form tumors in xenografts. Moreover it has been demonstrated that CD133+
cells are more resistant to radiation and standard chemotherapy than CD133- cells. Despite this other
investigations demonstrated that also CD133- cells can show the same characteristics as those positive for
CD133+. Hence, some inconsistencies among published data on CD133 function can be ascribed to different
causes questioning the main role as specific marker of cancer stem cells. In fact, many authors indicate that
CD133 is expressed both in differentiated and undifferentiated cells, and CD133- cancer cells can also initiate
tumors. Indeed, it is still a matter of debate whether CD133+ cells truly represent the ultimate tumorigenic
population. However, the belief that CD133 may act as a universal marker of CSCs has been met with a high
degree of controversy in the research community. In this review there is an attempt to highlight: i) the role and
function of CD133, with an overview of the current stage of knowledge regarding this molecule, ii) the difficulty
often encountered in its identification iii) the utility of CD133 expression as a prognostic marker. (AJTR1308002).
Keywords: Prominin-1 (CD133), cancer stem cells, epithelial-mesenchymal transition, glycosylation, epigenetic
regulation, circulating tumor cells
Address correspondence to: Dr. Giuseppe Pirozzi or Dr. Elena Irollo, Department of Experimental Oncology,
Istituto Nazionale Tumori Fonda-zione G. Pascale, Via Mariano Semmola, 80131 Naples, Italy. Tel: +39 81
5903534; Fax: +39 81 5903814; E-mail: g.pirozzi@istitutotumori.na.it (Giuseppe Pirozzi); e.irollo@istitutotumori.na.
it (Elena Irollo)
Review Article
CD133: to be or not to be, is this the real question?
Elena Irollo, Giuseppe Pirozzi
Department of Experimental Oncology, Istituto Nazionale Tumori Fondazione G. Pascale, Naples, Italy
Received August 7, 2013; Accepted August 31, 2013; Epub September 25, 2013; Published September 30, 2013
Abstract: CD133 (prominin-1) is a member of the transmembrane glycoprotein family and was initially described
as a specific marker to select human hematopoietic progenitor cells. Later it was recognised as an important
marker to identify and isolate the specific cell subpopulation termed “cancer stem cells” (CSCs). Many studies
showed that CD133+ cells have stemness properties such as self-renewal, differentiation ability, high
proliferation and they are also able to form tumors in xenografts. Moreover it has been demonstrated that CD133+
cells are more resistant to radiation and standard chemotherapy than CD133- cells. Despite this other
investigations demonstrated that also CD133- cells can show the same characteristics as those positive for
CD133+. Hence, some inconsistencies among published data on CD133 function can be ascribed to different
causes questioning the main role as specific marker of cancer stem cells. In fact, many authors indicate that
CD133 is expressed both in differentiated and undifferentiated cells, and CD133- cancer cells can also initiate
tumors. Indeed, it is still a matter of debate whether CD133+ cells truly represent the ultimate tumorigenic
population. However, the belief that CD133 may act as a universal marker of CSCs has been met with a high
degree of controversy in the research community. In this review there is an attempt to highlight: i) the role and
function of CD133, with an overview of the current stage of knowledge regarding this molecule, ii) the difficulty
often encountered in its identification iii) the utility of CD133 expression as a prognostic marker. (AJTR1308002).
Keywords: Prominin-1 (CD133), cancer stem cells, epithelial-mesenchymal transition, glycosylation, epigenetic
regulation, circulating tumor cells
Address correspondence to: Dr. Giuseppe Pirozzi or Dr. Elena Irollo, Department of Experimental Oncology,
Istituto Nazionale Tumori Fonda-zione G. Pascale, Via Mariano Semmola, 80131 Naples, Italy. Tel: +39 81
5903534; Fax: +39 81 5903814; E-mail: g.pirozzi@istitutotumori.na.it (Giuseppe Pirozzi); e.irollo@istitutotumori.na.
it (Elena Irollo)
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