| AIM:To investigate the expression, relationship and its clinicopathologic significance of the cancer stem cell makers CD44 and CD166 in primary colorectal carcinoma. Further to examine the quantity, location, distribution and morphological characteristics of colorectal cancer stem cells (Co-CSCs) CD44+/CD166+ in normal mucosa, adenoma and adenocarcinoma and to analyze their relationship with clinicopathological factors. To investigate the expressions and the morphologic features of the cancer stem cell makers CD44,CD166 in human colon cancer cell line(SW480).Methods:61 cases of human colorectal carcinoma,10 cases of normal mucosa and 18 cases of adenoma were collected and made into three tissue microarrays each containing 42 dots. Expressions of CD44,CD166 proteins were detected by SP (streptavidin HRP) immunohistochemical staining in these tissue microarrays. The locations of CD44 and CD166 double positive cells were detected by SP (streptavidin HRP) immunohistochemical staining and double immunohistochemical staining. The cell cycle of the three successive generations of human colon cancer cell line (SW480) was analyzed by Flow Cytometry. The morphologic features and the expressions of positive cells were detected by hematoxylin-eosin staining,SP (streptavidin HRP) immunohistochemical stainingResults:1. The expressions of CD44 and CD166 in colorectal carcinoma were significantly higher than in normal mucosa and adenoma with atypical hyperplasia. Significant relationship was found among the expression of CD44, pathological grade and depth of invasion (χ2=19.882,6.459, P<0.05). The expression of CD166 was also correlated with pathological grade and depth of invasion (χ2= 10.802,8.041, P＜0.05). Meanwhile, there was a positive correlation between the expressions of CD44 and CD166 (r=0.333, P=0.009<0.01)2. There was no CD44 and CD166 double positive cells in normal intestine mucosa, and a very small amount of CD44 and CD166 double positive cells in adenoma, and also CD44 double-positive cells being observed in colorectal carcinoma. The number of double positive cells accounted for 5%-15% of all tumor cells, and the cells were scattered or distributed focally along the basement of gland basal side. The cells with scarcely cytoplasm were round, and its nucleus was oval or high cylindrical, deep stained and homogeneous. The expressions of double positive cells in colorectal carcinoma were significantly higher than in adenoma (P<0.01). The quantity of double-positive cells was positively correlated with the differentiation of colorectal carcinoma (r=0.449 P=0.000<0.01). The quantity of double-positive cells was positively correlated with the depth of invasion (r=0.291 P=0.023<0.05).3. There were two kinds of morphology of SW480 tumor cells:one was large-polygon with abundant cytoplasm and bigger irregular nucleus, rough chromatin; Another one was small-round with scarcely cytoplasm and smaller nucleus, deep stained. Strong cytoplasm CD44,CD166 staining in SW480 cell line were observed. The number of small-round cells accounted for 10% to 20% of all tumor cells, were similar with the round cells of the colorectal carcinoma.Conclusion:1. As the surface markers of colorectal cancer stem cell, CD44 and CD166 are highly related to differentiation and invasion of colorectal carcinoma. Both of them are cooperative with each other. Therefore, detecting and analyzing their expression and relationship of two markers in colorectal carcinoma has a certain value to evaluation of the biological behavior and prognosis.2. The number of double-positive cells accounted for 1% to 15% of all tumor cells, and the cells were scattered or distributed focally along the basement of gland basal side. The cells with scarcely cytoplasm were round, and its nucleus was oval or high cylindrical, deep stained and homogeneous. The quantity of double-positive cells was negatively correlated with the differentiation of colorectal carcinoma. Cancer stem cells are the causes of tumor occurrence, development. To observe the number, location, distribution and morphology of Co-CSCs can contribute to the diagnosis and prognostic evaluation of colorectal carcinoma.3. The morphology and immunophenotype of small-round cells in human colon cancer cell line SW480 are similar with the small round cells in the colorectal carcinoma tissue. The small-round cells have the characteristics of tumor stem cells.
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