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Cancer stem cells are believed to be responsible for the cancer-initiating step and resistance to chemotherapy drugs. Studies have shown that cancer stem cells are silent and have no metabolic activity. The main reasons behind tumors resistant to therapies are lack of activity of cancer stem cells and division of cancer cells. This cell population, like normal stem cells, is capable of self-renewing and responsible for survival of tumor and its genetic and metabolic differences. Cancer stem cells can undergo chemotherapy during the treatment, but, the incidence of secondary tumor occurs due to unequal division of cancer stem cells and new tumor cells grow that are multi resistant to chemotherapeutic agents. Therefore, identifying and characterizing cancer stem cell will lead to a better understanding of its controlling pathways and developing better diagnostic and therapeutic methodologies in basic and clinical cancer researches. In this review the role of cancer stem cells in development of cancer and their heterogenic properties in gene expression and metabolism of the tumor has discussed. Finally, new therapeutic strategies that are often based on the use of nanocarriers are presented.

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Background and purpose: Angiogenesis provides proper nutrition and helps to the development and spread of cancer cells. Cancer stem cells are a rare population of tumor cells responsible for initiation, spreading and growth of cancer. Angiogenesis occurs more in cancer stem cells compared with other cancer cells. Ibuprofen, as a member of nonsteroidal anti-inflammatory drugs (NSAIDs) group is used for prevention and treatment of certain cancers. In the present study, we investigated the effect of ibuprofen on angiogenesis in gastric cancer stem cells.

Materials and methods: Gastric cancer stem cells of MKN45 cell line was isolated by spheroid colony formation technique. Gastric cancer stem cells were treated with various concentrations of ibuprofen. The angiogenic properties in gastric cancer stem cells treated with ibuprofen was compared with control cells using two-dimensional angiogenesis.

Results: Angiogenesis reduced in the cancer stem cells treated with ibuprofen compared with the control cancer stem cells.

Conclusion: Ibuprofen decreased angiogenesis in gastric cancer stem cells.

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Background and purpose: High cancer related mortality can be due to the presence of cancer stem cells (CSCs). Studies suggest aldehyde dehydrogenase (ALDH1) as a marker of CSCs. The aim of this study was to investigate its expression in colorectal cancer and also its association with clinicopathologic characteristics.
Materials and methods: In a retrospective study, patients with colorectal cancer attending Sari Imam Khomeini Hospital were enrolled. The intensity and distribution of ALDH1 expression in tumor and non-tumoral adjacent tissue samples were measured by immunohistochemistry. Data were analyzed using SPSS V18.
Results: Forty patients including 20 males and 20 females were studied. The frequency and intensity of ALDH1 expression in tumoral and non-tumoral tissues were not significantly different. The expression intensity was not related to age, type of adenocarcinoma, and tumor location, but it was found to be higher in women (P=0.08). Mild ALDH1 expression was higher in well-differentiated grade (P= 0.07). Discontinuous distribution was higher in non-mucinous adenocarcinoma (P= 0.06) and well-differentiated grade (P= 0.028).
Conclusion: In this study, ALDH1 expression was not significantly different in the samples of colorectal cancer and normal adjacent. But, higher intensity of expression in women and discontinuous distribution were observed in well-differentiated and non-mucinous samples. The role of ALDH1 as a CSC marker in colorectal cancer requires further investigations.