Invasive leader cells: metastatic oncotarget

Invasion into surrounding tissues is the first step of metastasis, and an understanding of the molecular basis of the invasive process may suggest novel strategies for anti-metastatic therapy. Breast tumors typically invade as adherent groups of cells, a process known as collective invasion. In vivo, collective invasion occurs within a complex tissue environment and involves interactions among the cancer cells, stromal cells, and the extracellular matrix (ECM). An additional challenge to understanding cancer invasion is that primary breast tumors contain diverse cancer cells with varied molecular phenotypes. It is difficult to determine the relative contribution of these subpopulations to invasion from analysis of histologic sections. We sought to reduce this complexity and t