Reticker-Flynn, N.E. et al. Nat. Commun. 3, 1122 (2012).

The deadly ability of cancers to spread depends on their complex interactions with the extracellular environment. Arrays of extracellular-matrix molecules have been used to screen for factors that determine whether cells can attach, but they are limited to testing just a handful of factors. Reticker-Flynn et al. now develop a large-scale, fully automated platform based on a 4,000-element polyacrylamide hydrogel–spotted array. The polyacrylamide pads can trap a wide range of molecules, allowing the researchers to measure adherence of labeled mouse lung adenocarcinoma cells to 38 matrix molecules either alone or in pairwise combinations. They found that adherence profiles of primary tumors and cells from different metastases are distinct and that the profiles depend on combinatorial interactions and correspond to molecules present at tumor sites in vivo.