Normal MECs are regarded as natural tumor suppressors due to their anti-tumorigenic, anti-angiogenic, and anti-invasive functions.141–145 In this context, they express tumor suppressor proteins including P63, tumor protein p73, laminin 1, and maspin.80,146,147 However, DCIS-associated MECs differ from normal MECs. The gene discussed is TP63; the disease is ductal breast carcinoma in situ.