The loading rates in the "Cell Adhesion Force Evaluation" section of the Material and Methods section are incorrect. The correct parameters h) and i) should be: h) plateau steps, for this set of data appear after a force plateau of at least 500 nm length at loading rates of less than 27pN/s (see step 2 in Fig. 3A). At loading rates between 27 and 40 pN/s the criterion was not clear enough to avoid false positive or negative step discrimination. i) steep steps consequently occur after an increase in force of at least 40 pN/s. The loading rates in the Results above the "Integrin Expression in PC3 and LNCaP Cells" section are incorrect. The corrected loading rates are: (loading rates between 27 and 40 pN/s ) was less than 7%.