Abstract

 Background and Objectives

 Uncontrolled self renewal plays a direct function in different types of carcinoma progression. Here we examined the expression of self renewal regulatory factors such as Oct4, Nanog, Sox2, Nucleostemin, Zfx, Bmi-1 in colon, prostate, bladder and liver cancers in human samples and cancer cell lines.

 Materials and Methods

 We used RT-PCR to examine the expression of these genes in 10 tumors of bladder, 5 tumors of prostate, 5 tumors of colon , 5 normal tissues of colon, and cancer cell lines. The expression of Oct-4 and Nucleostemin at protein level was further determined by immunocytochemical (ICC) analysis in cancer cell lines.

 Results

 We designed specific primers to amplify a segment of Oct4, Nanog, Sox2, Nucleostemin, Bmi and Zfx. As expected DNA fragment of these genes based on designated primer was amplified in the PCR reaction. We detected the expression of these genes in almost all of the examined tumor samples and cancer cell lines that we used. Oct4 and Nucleostemin proteins were expressed in both nuclear and cytoplasmic in cancer cell lines. No immunoreactivity was observed in negative controls, which were incubated in the absence of primary antibody.

 Conclusions

 Collectively, our results indicated that in a tumor population a rare subpopulation of cells within the tumor cell mass has the potential of self renewal, and suggested that their expression can be used as potential tumor markers in diagnosis and/or prognosis of tumors. These results confirm the potential value of the cancer stem-cell theory in cancer therapy.