BACKGROUND: Colorectal cancer is a common malignant tumor in digestive tract. Theory of tumor stem cells (TSCs) offers a new approach to understand the development mechanism of colorectal cancer. OBJECTIVE: To review the progress in the existence, origin and identification of colorectal cancer stem cells (Co-CSCs). RETRIEVAL STRATEGY: Pubmed was undertaken to identify relevant articles published from January 1990 to July 2007 with the of "colorectal cancer,stem cell,tumor stem cells" in English.At the same time, Vip database was undertaken to identify the relevant articles published between January 1990 and July 2007 with the key words of "colorectal cancer, stem cell, tumor stem cells" in Chinese. The data were selected primarily, and then quotations of each article were checked. Inclusive criterion: the articles related to the advances of the existence, origin and identification of Co-CSCs were selected. Exclusive criterion: the articles with repetitive research were excluded. Totally 63 relevant articles were selected and 33 of them met the inclusive criterion. The 30 excluded articles were of old or repetitive content. LITERATURE EVALUATION: Of the 33 inclusive articles, 28 were on the existence and origin of Co-CSCs, 4 were about the isolation and identification of Co-CSCs, and 1 was about the problems and prospect. DATA SYNTHESIS: TSCs is a rare population of cells in tumor tissues with infinitely proliferative and self-renewal potential that drive the formation and growth of tumors. It may become a new target to eradicate malignant tumor. TSCs have been discovered in leukemia and some solid tumors. Intestine stem cells are poorly differentiated. Its phenotype is difficult to identify. There are many reports on the quantity, location, origin, function and relation with intestinal disease. Co-CSCs have been isolated and identified as EpCAMhigh/CD44+ cells recently, which accelerate to understand the mechanism of colorectal cancer. CONCLUSION: The discovery of Co-CSCs is one of the advances in researching of malignant tumor. TSCs may become a new target to eradicate malignant tumor, and brings hope to cure it.

BACKGROUND: Cancer stem cells have bean a hot topic in life science research. EpCAMhigh/CD44+ colorectal cancer stem cells are beneficial to observe morphological characteristics and distribution of cancer stem cells.OBJECTIVE: To investigate the quantity, location, distribution and hematoxylin-easin staining morphologic features of colorectal cancer stem cells (Co-CSCs).DESIGN, "rIME AND SETrlNG: The observational study was performed at the Department of Pathology, Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA from March to August 2008.MATERIALS: A total of 67 colorectal cancer paraffin embedding samples were collected from 200512007 archive at the Department of Pathology, Lanzhou General Hospital of Lanzhou Military Area Command of Chinese PLA, comprising 27 males and 40 females, aged 29 90 years.METHODS: EpCAM and CD44 was used to label cancer stem cells in paraffin embedding colorectal cancer samples. The locations of EpCAM and CD44 double positive cells were detected by SP(streptavidin HRP) immunohistochemical staining and double immunohistochemical staining. The morphologic features of them were investigated on hematoxylin-easin staining at the same position.MAIN OUTCOME MEASURES: Number, location, distribution of EpCAM and CD44-posltive cells, and morphology following hematoxylin-eosin staining.RESULTS: The number of double-positive cells accounted for 0.1% to 30.0% of all tumor cells, and the cells were scattered or distributed focally along the basement of glandular-like structure. The cells with scarcely cytoplasm were cube or oval, and its nucleus was oval or high cylindrical, deep stained and homogeneous; The quantity of double-positive cells were negatively correlated with the differentiation of colorectal cancer.CONCLUSION: Cancer stem cells are the causes of tumor development, metastasis and recurrence and drug resistance. To observe the number, location, distribution and morphology of Co-CSCs and to analyze the relationship between Co-CSCs and pathological parameters will provide guidance for the diagnosis, staging, prognostic evaluation and clinical prognosis of cotorectal carcinoma.