KRT5 and neoplasm: AP-2α/β isoforms: AP-2α/β protein expression was studied in 309 ER negative patients and showed no significant association with either tumour size, lymph node stage, histological grade, development of metastasis, vascular invasion, tumour type, menopausal status, PgR, CK19, HER3, HER4, E-cadherin, EGFR, CK5/6, CK14, p53 or Bcl2 (data not shown).