We demonstrate that the effects of cell–cell contact and of changes in cell shape have only a minor effect on the angular distribution of light scattering from mammalian fibroblast cells. This result is important for the development of light scattering as a noninvasive tool for tissue diagnostics such as cancer detection. Changes in cell organization that are not accompanied by changes in internal cellular structure may not be measurable. On the other hand, changes in internal cellular structure should be measurable without interference from changes in overall cellular organization. The second major result of this work is that there are small but significant differences between light scattering of tumorigenic and nontumorigenic cells grown in a three-dimensional culture system. The cause of the differences in light scattering are likely due to the nontumorigenic cells arresting in the G1 phase of the cell cycle, while the tumorigenic cells continue to proliferate.