We report the expression profiles of MCF10A cells encapsulated in hydrogels of varying stiffness and composition. Cells were encapsulated for 7 days in either 1.) soft alginate and reconstituted basement membrane (rBM), 2.) stiff alginate and rBM, 3,) soft col-1 and rBM, or 4.) stiff col-1. We find global gene expression changes in response to enhanced ECM stiffness, independent of expression changes in response to col-1 exposure. These results provide a comprehensive study of the gene expression changes associated with increased ECM stiffness in addition to the gene expression changes associated with increased col-1 concentration in combination with, and independent of, ECM stiffness. Overall design: Expression profiling of MCF10A cells in four hydrogel conditions were sequenced in duplicate via Illumina HiSeq.