Tamoxifen-resistant breast cancer cells possess cancer stem-like cell properties / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cancer stem cells (CSCs) are the cause of cancer recurrence because they are resistant to conventional therapy and contribute to cancer growth and metastasis. Endocrinotherapy is the most common breast cancer therapy and acquired tamoxifen (TAM) resistance is the main reason for endocrinotherapy failure during such therapy. Although acquired resistance to endocrine treatment has been extensively studied, the underlying mechanisms are unclear. We hypothesized that breast CSCs played an important role in TAM-induced resistance during breast cancer therapy. Therefore, we investigated the biological characteristics of TAM-resistant (TAM-R) breast cancer cells.</p><p><b>METHODS</b>Mammosphere formation and tumorigenicity of wild-type (WT) and TAM-R MCF7 cells were tested by a mammosphere assay and mouse tumor xenografts respectively. Stem-cell markers (SOX-2, OCT-4, and CD133) and epithelial-mesenchymal transition (EMT) markers were tested by quantitative real-time (qRT)-PCR. Morphological observation was performed to characterize EMT.</p><p><b>RESULTS</b>After induction of TAM resistance, TAM-R MCF7 cells exhibited increased proliferation in the presence of TAM compared to that of WT MCF7 cells (P < 0.05), indicating enhanced TAM resistance of TAM-R MCF7 cells compared to that of WT MCF7 cells. TAM-R MCF7 cells showed enhanced mammosphere formation and tumorigenicity in nude mice compared to that of WT MCF7 cells (P < 0.01), demonstrating the elevated CSC properties of TAM-R MCF7 cells. Consistently, qRT-PCR revealed that TAM-R MCF7 cells expressed increased mRNA levels of stem cell markers including SOX-2, OCT-4, and CD133, compared to those of WT MCF7 cells (P < 0.05). Morphologically, TAM-R MCF7 cells showed a fibroblastic phenotype, but WT MCF7 cells were epithelial-like. After induction of TAM resistance, qRT-PCR indicated that MCF7 cells expressed increased mRNA levels of Snail, vimentin, and N-cadherin and decreased levels of E-cadherin, which are considered as EMT characteristics (P < 0.05).</p><p><b>CONCLUSION</b>TAM-R MCF7 cells possess CSC characteristics and may be responsible for TAM resistance during breast cancer therapy.</p>

Bioinformatics analysis of breast cancer bone metastasis related gene-CXCR4

OBJECTIVE@#To analyze breast cancer bone metastasis related gene-CXCR4.@*METHODS@#This research screened breast cancer bone metastasis related genes by high-flux gene chip.@*RESULTS@#It was found that the expressions of 396 genes were different including 165 up-regulations and 231 down-regulations. The expression of chemokine receptor CXCR4 was obviously up-regulated in the tissue with breast cancer bone metastasis. Compared with the tissue without bone metastasis, there was significant difference, which indicated that CXCR4 played a vital role in breast cancer bone metastasis.@*CONCLUSIONS@#The bioinformatics analysis of CXCR4 can provide a certain basis for the occurrence and diagnosis of breast cancer bone metastasis, target gene therapy and evaluation of prognosis.

Long-term results of surgical treatment of stomach cancer: clinical experience of forty years from Sun Yat-sen University Cancer Center / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the approaches to improve therapeutic effect of stomach cancer by analysis of the long-term results of surgical treatment of this disease.</p><p><b>METHODS</b>Prognostic factors of stomach cancer were analyzed by Cox multivariate regression model based on clinical data of 2561 stomach cancer cases who underwent surgical treatment from 1964 to 2004 at Sun Yat-sen University Cancer Center. Survival rates were calculated by life table method.</p><p><b>RESULTS</b>Gastrectomy was performed for 1950 cases with resectability of 76.1%, among which there were 1192 cases of curative resection (46.5%) and 758 cases of non-curative resection (29.6%). The other 611 cases of palliative operation included bypass procedures and laparotomy. Operative mortality of all cases was 0.8% and morbidity was 5.1%. For all cases the 1-, 3- and 5-year survival rate was 52.4%, 38.6% and 35.5%, respectively. The stage-specific 5-year survival rate was 86.8% (Stage I), 58.7% (Stage II), 28.4% (Stage III) and 7.6% (Stage IV), respectively. The 5-year survival after curative resection in the period of 40 years was 45.5%, and increased to 52.7% in the last two decades and 61.8% in recent decade. Stage-specific case proportion during the earlier two decades was 1.4% (Stage I), 10.6% (Stage II), 23.1% (Stage III) and 64.9% (Stage IV), respectively, and that during the recent two decades was 9.3%, 18.5%, 35.3% and 36.8%, respectively. The 5-year survival rate of cases during the earlier two decades was 18.0% and increased to 37.5% during the recent two decades. Multivariate analysis indicated that main prognostic factors of stomach cancer included TNM staging, curative resection and multidisciplinary treatment.</p><p><b>CONCLUSIONS</b>Early detection and curative resection were the most important measures to improve therapeutic effect of stomach cancer. A surgery-predominant multidisciplinary treatment individualizing biological characteristics of tumor, staging of disease and tumor site will contribute to improvement of therapeutic effect of stomach cancer.</p>