ERBB2 and ductal breast carcinoma in situ: For ERBB2 (Fig. 5d), S3R prioritized CCND1 (regulator of cell proliferation), a DCIS-enriched local neighbourhood (ductal epithelial context where HER2 activity concentrates), and Niche 2 (epithelial/tumour-dense), together consistent with HER2 (ERBB2) signaling coupled with CCND1 in compact epithelial territories [45].