Abstract Background Gastric cancer remains one of the leading causes of cancer‐associated mortalities globally. Accumulating evidence support the presence of gastric cancer stem cells (CSCs) and their role in the pathogenesis and therapeutic challenges of gastric cancer. MicroRNAs (miRNAs) may be influenced by the cellular differentiative state and as critical regulators of the cellular fate in development and cancer, can modulate the behavior of CSCs too. Here, we aimed to investigate the expression relevance of three prognostic miRNAs (miR‐21, miR‐10b, and miR‐146a) in CSCs of AGS and MKN‐45 gastric cancer cell lines. Methods Serial sphere‐forming assay in serum‐free culture medium was used to enrich the cellular population with stem‐like properties. Gastro‐spheres were characterized by evaluating the stemness gene expression, clonogenicity, and resistance to docetaxel and cisplatin in comparison with their parental cells. The expression level of miRNAs in gastro‐spheres and their parental cells was measured using quantitative reverse transcription polymerase chain reaction. Results Gastro‐spheres from both cell lines exhibit stem‐like properties: upregulated stemness associated genes ( P < 0.05), more colonogenicity and more resistance to docetaxel ( P < 0.05). MKN‐45 gastro‐spheres exhibited upregulated expression of miR‐21 (1.8‐folds), miR‐10b (1.34‐folds) and miR‐146a (4.8‐folds; P < 0.05) compared with the parental cells. AGS‐derived gastro‐spheres showed upregulation of miR‐21 (4.7‐folds; P < 0.01), miR‐10b (15.2‐folds; P < 0.001) and miR‐146a (39.3‐folds; P < 0.05). Conclusion Our data exhibited upregulation of miR‐21, miR‐10b, and miR‐146a in the stem‐like gastro‐spheres; however; their function in gastric CSCs remains to be verified by further experiments.
Introduction As many as 30% of node-negative breast cancer patients relapse within five years, suggesting that current histological detection methods are inadequate for identifying metastatic disease. Detecting small number of cancer cells in the breast tissue or lymph node by reverse transcription-polymerase chain reaction (RT-PCR) assays using a combination of tissue and cancer specific markers might be very useful in the early detection or monitoring of the treatment. Mammaglobin is a member of the uteroglobin gene family and appears to be expressed only in breast tissue. Carcinoembryonic antigen has been the preferred molecular marker for detection of micro metastases in lymph nodes in almost all carcinomas. Materials and methods Samples were collected from randomly chosen breast cancer patients undergoing modified mastectomy or breast conserving surgery between September 2003 and July 2004. RT-PCR was applied to study the expression of MMG and CEA markers. Breast cancer micrometastases in axillary lymph nodes were also assessed. Results The MMG marker was positive in 9/10 normal breast tissues, 3/3 breast fibroadenomas and 37/39 of breast carcinoma tissues, giving an overall sensitivity of 94%. The sensitivity was 80% for metastatic lymph node samples. On the other hand CEA showed 95% sensitivity for malignant breast tumors and 100% sensitivity for metastatic lymph nodes. Conclusions RT-PCR using a combination of MMG and CEA markers is a powerful tool to complement current routine histopathology techniques for detection of breast cancer metastasis in axillary nodes.
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