Differently, HER2 amplification mainly occurs with two distinct amplification mechanisms: 30% of HER2-positive breast tumors present a Dmin amplification mechanism with a pattern similar to the ones described for MDM2 (Figure 5A), but the majority of HER2-positive breast cases (~60%) involve intrachromosomal regions called homogeneously staining regions (HSR) (Figure 5B) [67,68]. The gene discussed is MDM2; the disease is breast neoplasm.