| ObjectiveTo investigate the expression and its clinical significance of the cancer stem cells maker CD44and the human embryonic stem cells maker Oct4in primary colorectal adenocarcinoma and in human colon cancer cell lines (SW620/SW480), respectively. Furthermore, to observe and compare the quantities, distribution and morphological characteristics of CD44+/Oct4+cells in normal mucosa, adenoma, adenocarcinoma and human colon cancer cell lines (SW620/SW480), respectively, and explore the potential value of CD44+/Oct4+as the markers of colorectal cancer stem cells.MethodsThe CD44+, Oct4+and CD44+/Oct4+cells were marked in normal mucosa (18cases), adenoma (18cases), primary colorectal adenocarcinoma (108cases) and human colon cancer cell lines (SW620/SW480) by tissue microarray, immunohistochemical staining and double immunohistochemical staining technology, respectively. Meanwhile their quantities, distribution, morphological characteristics and clinicopathologic relationship were analyzed and IBM SPSS20.0software was used for statistical analysis. Enumeration data, graded data and comparison of mean were performed using χ2test, spearman rank correlation test and two independent samples t-test or one-way analysis of variance, respectively, and P value less than0.05was considered statistical significance.Results1. The positive expression rates of CD44and Oct4in normal mucosa, adenoma and primary colorectal adenocarcinoma were16.67%(3/18) and5.56%(1/18),44.44%(8/18) and33.33%(6/18),80.19%(85/106) and65.09%(69/106). The differences in the positive rates of CD44and Oct4among the groups were statistically significant (P<0.05). The expressions of CD44and Oct4 were significantly related to the degree of tumor cell differentiation, metastasis of lymph node and Dukes stage (P<0.05). Meanwhile the expressions of CD44was statistically related to the depth of tumor invasion (P<0.05). The analysis of spearman rank correlation showed that the expressions of CD44and Oct4were positively correlated with the degree of pathological changes and Dukes stage (r=0.486/0.417,0.387/0.272, P<0.01) and were negatively correlated with the degree of tumor cell differentiation (r=-0.262/-0.365, P<0.01). Meanwhile, there was a positive correlation between the expressions of CD44and Oct4(r=0.438, P<0.01).2. In normal mucosa, adenoma and primary colorectal adenocarcinoma, the amount of CD44+/Oct4+cells accounted for0%,0%-3.12%and0%-23.15%of all tumor cells, and the average was0%,0.51%and7.05%, the differences were statistically significant by using two independent samples t-test (t’=-9.832, P<0.05). In high, median and low differentiation colorectal adenocarcinoma, the amount of CD44+/Oct4+cells accounted for0%-16.38%,0%-17.54%and2.31%-23.15%of all tumor cells, and the average was3.17%,5.37%and12.67%, the differences were statistically significant by using one-way analysis of variance (F=27.391, P<0.05). The CD44+/Oct4+cells with scarcely cytoplasm in colorectal adenocarcinoma were small nucleus, which was round or oval, deep stained and homogeneous, similar to a lymphocytes. These cells were scattered or distributed focally along the side of the gland basement wall or the side of co-wall in colorectal carcinomas.3. The amount of CD44+/Oct4+cells was not correlated with sex, age, locations, size, gross type of the tumor (P>0.05), but was positively correlated with the differentiation, invasion of tumor cell, metastasis of lymph node and Dukes stage statistically (P<0.05). The analysis of spearman rank correlation showed that the amount of CD44+/Oct4+cells was positively correlated with the degree of pathological changes and Dukes stage (r=0.644, P<0.01; r=0.396, P<0.01).and was negatively correlated with the degree of tumor cell differentiation (r=-0.579, P<0.01).4. Most of the CD44+/Oct4+cells were small round and mono-polar in human colon cancer cell lines SW620and SW480. The average of CD44+/Oct4+cells’ quantity was8.18%, and7.25%, which was similar to the average of double positive cells’ quantity (7.05%) in solid tumor. The difference was not statistically significant by using two independent samples t-test (t’=-1.471, P>0.05and t’=-0.227, P>0.05).Conclusion1. The amount of CD44+/Oct4+cells is positively correlated with malignant degree of tumor indicated by some clinical pathologic parameters. It can be used as an indicator to evaluate the biological behavior of tumor and prognosis of patients. 2. In human colon cancer cell lines SW620and SW480, the quantity and morphological characteristics of CD44+/Oct4+cells are similar to the solid tumor tissues, and to further testify the feasibility of CD44+/Oct4+immunophenotype as a marker of colorectal cancer stem cells in cytology level. It can be used to separate and identify colorectal cancer stem cells.3. The quantity of CD44+/Oct4+cells is little in colorectal adenocarcinoma. The distribution and morphological characteristics of double positive cells are similar to normal stem cells located in the base membrane of bowel mucosa. Hence, the CD44+/Oct4+immunophenotype may be a potential valuable marker of colorectal cancer stem cells. It is an effective index for predicting tumor recurrence, metastasis and prognosis, and it can be used as a therapeutic target for colorectal cancer stem cells targeting therapy in the future. |
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