In this unique project, large palpable DCIS > 5cm without evidence of invasive cancer will be compared to age and molecularly matched invasive cancers from the I SPY 2 TRIAL of stage 2/3 tumors in an effort to understand what prevents invasion despite the development of a large palpable DCIS lesion. By exploring single cell sequencing, mutational analysis, immune multiplex profiling and stromal investigations, the team hopes to illuminate the mechanisms that prevent DCIS from progressing to invasive cancer.