Agnieszka and colleagues, by the use of a series of human breast carcinomas with matched lymph node metastasis, showed that P-cadherin expression varied considerably (increased or decreased) between primary tumour and nodal metastasis (29.2 % of total cases), and that all the primary cases with P-cadherin enhancement in the lymph nodes were triple negative breast carcinomas (i.e., breast carcinomas that are negative for ER, PR and HER2). Here, PGR is linked to breast carcinoma.