ERBB2 and invasive ductal breast carcinoma: The increase in gene expression was even more obvious in the second patient, in whom prior to surgery for invasive ductal carcinoma (pT1c N1a (1/49) L1 V0 G3 R0, M0 ER: 90%, PR: 20%, HER-2/ neu-negative) all of the 12 randomly picked surface EpCAM-positive cells tested showed no relevant expression of any of the genes.