All seven of a set of CD34 monoclonal antibodies that recognize epitopes on an approximately 110 Kd glycoprotein on human hemopoietic progenitor cells also bind to vascular endothelium. Capillaries of most tissues are CD34 positive, as are umbilical artery and, to a lesser extent, vein, but the endothelium of most large vessels and the endothelium of placental sinuses are not. Angioblastoma cells and parafollicular mesenchymal cells in fetal skin are also CD34 positive, as are some stromal elements. An approximately 110 Kd protein can be identified by Western blot analysis with CD34 antibodies in detergent extracts of freshly isolated umbilical vessel endothelial cells, and CD34 mRNA is present in cultured umbilical vein cells as well as other tissues rich in vascular endothelium (breast, placenta). These data indicate that the binding of CD34 antibodies to vascular endothelium is to the CD34 gene product, and not to crossreactive epitopes. Despite the presence of CD34 mRNA in cultured, proliferating endothelial cells, the latter do not bind CD34 antibodies. In addition, CD34 antigen cannot be upregulated by growth factors. We conclude that under these conditions, CD34 protein is downregulated or processed into another form that is unreactive with CD34 antibodies. Electron microscopy of umbilical artery, breast, and kidney capillary vessels reveals that in all three sites, CD34 molecules are concentrated on membrane processes, many of which interdigitate between adjacent endothelial cells. However, well-established endothelial cell contacts with tight junctions are CD34 negative. CD34 may function as an adhesion molecule on both endothelial cells and hematopoietic progenitors.

PURPOSE Standard adjuvant chemotherapy for triple-negative breast cancer (TNBC) includes a taxane and an anthracycline. Concomitant capecitabine may be beneficial, but robust data to support this are lacking. The efficacy and safety of the addition of capecitabine into the TNBC adjuvant treatment regimen was evaluated. PATIENTS AND METHODS This randomized, open-label, phase III trial was conducted in China. Eligible female patients with early TNBC after definitive surgery were randomly assigned (1:1) to either capecitabine (3 cycles of capecitabine and docetaxel followed by 3 cycles of capecitabine, epirubicin, and cyclophosphamide) or control treatment (3 cycles of docetaxel followed by 3 cycles of fluorouracil, epirubicin, and cyclophosphamide). Randomization was centralized without stratification. The primary end point was disease-free survival (DFS). RESULTS Between June 2012 and December 2013, 636 patients with TNBC were screened, and 585 were randomly assigned to treatment (control, 288; capecitabine, 297). Median follow-up was 67 months. The 5-year DFS rate was higher for capecitabine than for control treatment (86.3% v 80.4%; hazard ratio, 0.66; 95% CI, 0.44 to 0.99; P = .044). Five-year overall survival rates were numerically higher but not significantly improved (capecitabine, 93.3%; control, 90.7%). Overall, 39.1% of patients had capecitabine dose reductions, and 8.4% reported grade ≥ 3 hand-foot syndrome. The most common grade ≥ 3 hematologic toxicities were neutropenia (capecitabine, 136 [45.8%]; control, 118 [41.0%]) and febrile neutropenia (capecitabine, 50 [16.8%]; control, 46 [16.0%]). Safety data were similar to the known capecitabine safety profile and generally comparable between arms. CONCLUSION Capecitabine when added to 3 cycles of docetaxel followed by 3 cycles of a 3-drug anthracycline combination containing capecitabine instead of fluorouracil significantly improved DFS in TNBC without new safety concerns.

The incidence of young cases of breast cancer is higher in China compared to the western world. We aimed to explore differences in risk factors, clinicopathological features and treatment modes of young female breast cancer compared to older patients in West China. We collected clinical information from 12,209 female breast cancer patients in West China, including risk factors, clinicopathological features and treatment modes, from January 2010 to December 2012. Chi-square tests and the multivariate logistic regression analysis were applied for statistical analysis. There were 2,682 young (≤40 years) cases and 9,527 older cases at the time of breast cancer diagnosis. Young patients had a greater tumor diameter at diagnosis, and a higher probability of axillary lymph node and distant metastasis (P < 0.05). The progesterone receptor positive expression rate, estrogen receptor/progesterone receptor double positive expression rate, and human epidermal growth factor receptor 2 (HER2) negative expression rate was higher in young patients compared to older patients (P < 0.05). For young patients, the age at menarche was earlier, they had lower marriage rates, fewer pregnancies and births, and a lower breastfeeding rate (P < 0.05). A higher proportion of young patients underwent advanced operations, neoadjuvant and adjuvant chemotherapy, radiotherapy, and endocrine therapy compared to older patients (P < 0.05). We found significant differences in the clinicopathological features, risk factors and treatment modes between young (≤40 years) and older (>40 years) female breast cancer patients in West China. As some of these results differ from those found in the western female population, it is likely that the mechanism of tumorigenesis of young female breast cancer patients in West China may differ from that in western developed countries. Further investigation into the regional differences in breast cancer tumorigenesis is warranted.

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