Since PKD1 expression was correlated with the invasive phenotype of breast cancer cell lines (Table 2) and since its highest expression level was observed in a mesenchymal-like breast cancer cell line (i.e. Hs578T), the relationship between PKD1 expression levels and EGFR, vimentin and E-cadherin levels was analysed. The gene discussed is EGFR; the disease is breast cancer.