As the most commonly occurring cancer in women worldwide,breast cancer poses a formidable public health challenge on a global scale.Breast cancer consists of a group of biologically and molecularly heterogeneous diseases originated from the breast.While the risk factors associated with this cancer varies with respect to other cancers,genetic predisposition,most notably mutations in BRCA1 or BRCA2 gene,is an important causative factor for this malignancy.Breast cancers can begin in different areas of the breast,such as the ducts,the lobules,or the tissue in between.Within the large group of diverse breast carcinomas,there are various denoted types of breast cancer based on their invasiveness relative to the primary tumor sites.It is important to distinguish between the various subtypes because they have different prognoses and treatment implications.As there are remarkable parallels between normal development and breast cancer progression at the molecular level,it has been postulated that breast cancer may be derived from mammary cancer stem cells.Normal breast development and mammary stem cells are regulated by several signaling pathways,such as estrogen receptors(ERs),HER2,and Wnt/b-catenin signaling pathways,which control stem cell proliferation,cell death,cell differentiation,and cell motility.Furthermore,emerging evidence indicates that epigenetic regulations and noncoding RNAs may play important roles in breast cancer development and may contribute to the heterogeneity and metastatic aspects of breast cancer,especially for triple-negative breast cancer.This review provides a comprehensive survey of the molecular,cellular and genetic aspects of breast cancer.
As the most commonly occurring cancer in women worldwide,breast cancer poses a formidable public health challenge on a global scale.Breast cancer consists of a group of biologically and molecularly heterogeneous diseases originated from the breast.While the risk factors associated with this cancer varies with respect to other cancers,genetic predisposition,most notably mutations in BRCA1 or BRCA2 gene,is an important causative factor for this malignancy.Breast cancers can begin in different areas of the breast,such as the ducts,the lobules,or the tissue in between.Within the large group of diverse breast carcinomas,there are various denoted types of breast cancer based on their invasiveness relative to the primary tumor sites.It is important to distinguish between the various subtypes because they have different prognoses and treatment implications.As there are remarkable parallels between normal development and breast cancer progression at the molecular level,it has been postulated that breast cancer may be derived from mammary cancer stem cells.Normal breast development and mammary stem cells are regulated by several signaling pathways,such as estrogen receptors(ERs),HER2,and Wnt/b-catenin signaling pathways,which control stem cell proliferation,cell death,cell differentiation,and cell motility.Furthermore,emerging evidence indicates that epigenetic regulations and noncoding RNAs may play important roles in breast cancer development and may contribute to the heterogeneity and metastatic aspects of breast cancer,especially for triple-negative breast cancer.This review provides a comprehensive survey of the molecular,cellular and genetic aspects of breast cancer.
OBJECTIVE To evaluate the REGγ expression in gastric cancer tissue and gastric cancer cell lines of various differentiation levels and its clinical significance. METHODS Immunohistochemistry was used to detect the expression of REGγ protein in 70 specimens of gastric cancer and 30 specimens of normal gastric mucosa. The relationship between the expression of REGγ protein and the biological behaviors of gastric cancer was analyzed. RT-PCR and Western blot were used to detect the mRNA level and the protein expression of REGγ in normal gastric cell line GES-1, well differentiated gastric cancer cell line MKN-28, moderately differentiated gastric cancer cell line SGC-7901 and poorly differentiated gastric cancer cell line BGC-823. RESULTS The expression rate of REGγ protein in gastric cancer tissue （52/70, 74.29%） was significantly higher than that in normal gastric tissue （12/30, 40%） （P 〈 0.01）. The expression rate of REGγ was correlated with tumor size （P 〈 0.01）, lymph node metastasis （P 〈 0.05）, differentiation degree （P 〈 0.01）, infiltration depth （P 〈 0.01） and distant metastasis （P 〈 0.05）. RT-PCR analysis showed that the expression of REGγ mRNA was 0.459 ± 0.079 in the normal gastric mucosa cell ling 0.588 ±0.118 in the well differentiated gastric cancer cell line, 0.715±0.066 in the moderately differentiated gastric cancer cell line, and 0.873 ± 0.099 in the poorly differentiated gastric cancer cell line, showing a negative correlation between REGγ mRNA expression and differentiation level （P 〈 0.05）. Western blot analysis showed that the expression of REGγ protein was 0.712±0.065 in the normal gastric mucosa cell line, 1.176±0.185 in the well differentiated gastric cancer cell line, 1.533 ± 0.127 in the moderately differentiated gastric cancer cell line, and 2.061± 0.398 in the poorly differentiated gastric cancer cell line, showing a negative correlation between REGγ protein expression and differentiation level （P 〈 0.05）. CONCLUSIO
