In April of 2013, California will be the 5th state mandating that a physician notify a patient if they have dense breast tissue. Eleven more states, and now the federal government, have similar laws in process today. Thanks to the efforts of an advocacy group of breast cancer survivors, D.E.N.S.E (Density Education National Survivors Network), women will now be informed that their condition interferes with the effectiveness of mammograms to identify tumors in their breasts.