We consistently saw high LAMP2 staining in regions of tumours expected to be acidic, such as the peri-luminal region of DCIS and cells in areas of microinvasion (Figs 6d and 7b; Supplementary Figs 6A and 7A), which are consistent with our previous observation in DWC experiments that invasion is stimulated by acidosis8. The gene discussed is LAMP2; the disease is ductal breast carcinoma in situ.