Under malignant conditions PMCA calcium pumps have been associated to breast cancer outcomes since PMCA2 has been positively associated with HER2 expression in human ductal carcinoma in situ and PMCA2 null mice develop less tumours when crossed with a HER2 cancer mouse model, indicating that it may be particularly important in HER2+ breast cancers growth [48]. The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.