ERBB2 and neoplasm: Importantly, a low variation in staining intensity was found for ER, PR, HER2, CK5/6 and EGFR expression in the primary tumour and nodal metastasis (over 90 % of the cases showed the same level of expression for these markers), suggesting that P-cadherin may be a candidate prognostic biomarker to explore in the lymph nodes [69].