Figure 3 Model of the linear progresion from normal, to hyperplastic enlogated lobular units ( HELU), to atypical ductal hyperplasia (ADH), to ductal carcinoma in situ ( DCIS), to occult invasive breast cancer ( IBC), to IBC that has exceeded detection threshold and can be diagnosed by mammogram. Kinetic modeling data suggest that it takes 10 to 20 years for the progression from atypical hyperplasia to a clinically detectable tumor