This Review describes the work conducted by the TRANSBIG consortium in the development of the MINDACT (Microarray In Node negative Disease may Avoid ChemoTherapy) trial. The goal of the trial is to provide definitive evidence regarding the clinical relevance of the 70-gene prognosis signature, and to assess the performance of this signature compared with that of traditional prognostic indicators for assigning adjuvant chemotherapy to patients with node-negative breast cancer. We outline the background work and the key questions in node-negative early-stage breast cancer, and then focus on the MINDACT trial design and statistical considerations. The challenges inherent in this trial in terms of logistics, implementation and interpretation of the results are also discussed. We hope that this article will trigger further discussion about the difficulties of setting up and analyzing trials aimed at establishing the worth of new methods for better selection of patients for cancer treatment.

The study of lymphatic endothelial cells and lymphangiogenesis has, in the past, been hampered by the lack of lymphatic endothelial-specific markers. The recent discovery of several such markers has permitted the isolation of lymphatic endothelial cells (LECs) from human skin. However, cell numbers are limited and purity is variable with the different isolation procedures. To overcome these problems, we have transfected human dermal microvascular endothelial cells (HDMVECs) with a retrovirus containing the coding region of human telomerase reverse transcriptase (hTERT), and have produced a cell line, hTERT-HDLEC, with an extended lifespan. hTERT-HDLEC exhibit a typical cobblestone morphology when grown in culture, are contact-inhibited, and express endothelial cell-specific markers. hTERT-HDLEC also express the recognized lymphatic markers, Prox-1, LYVE-1 and podoplanin, as well as integrin ␣9, but do not express CD34. They also form tube-like structures in three-dimensional collagen gels when stimulated with vascular endothelial growth factors -A and -C. Based on these currently recognized criteria, these cells are LEC. Surprisingly, we also found that the widely studied HMEC-1 cell line expresses recognized lymphatic markers; however, these cells are also CD34-positive. In summary, the ectopic expression of hTERT increases the life span of LECs and does not affect their capacity to form tubelike structures in a collagen matrix. The production and characterization of hTERT-HDLEC will facilitate the study of the properties of lymphatic endothelium in vitro. The blood and lymphatic vascular systems are anatomically and histologically closely related but distinct, and do not anastomose except at the level of the main lymphatic ducts. The blood vascular system supplies nutrients and oxygen to the body while the lymphatic vasculature is crucial for immune cell traffic and the uptake of extracellular fluid. The formation of new blood vessels from pre-existing blood vessels (angiogenesis) occurs in physiological (eg, postnatal growth, inflammation, and tissue repair) and pathological (eg, tumor recruitment of blood vessels) settings. Lymphangiogenesis is the formation of new lymphatic vessels from pre-existing lymphatic capillaries, and occurs in similar settings. Blood endothelial cells (BECs) and lymphatic endothelial cells (LECs) are quiescent cells that line the lumina of blood and lymphatic vessels.The lymphatic system has traditionally been overshadowed by the greater emphasis placed on the blood vascular system. This has been due in part to the absence of suitable markers that distinguish lymphatic from blood vascular endothelium. In the past few years, this limitation has been overcome. Lymphatic markers include LYVE-1, a lymphatic endothelial receptor for the extracellular matrix/lymphatic fluid glycosaminoglycan hyaluronan; 1 Prox-1, a homeobox gene product involved in regulating early lymphatic development; 2 podoplanin, a glomerular podocyte membrane mucoprotein; 3 and vascular endothelial growth factor re...

Funding sourcesThe Belgian Health Care Knowledge Centre (KCE) funded and sponsored the trial via the KCE Trials Programme (study ID KCE16012), a national public funding programme of noncommercial trials. No funding from the manufacturers of the study devices was received. Involvement of the sponsor included refinement of the study design and statistical analyses but they were not involved in data collection. KCE members reviewed the manuscript for statistical correctness and interpretation. The corresponding author had the final responsibility for the decision to publish.