ERBB2 and hepatocellular carcinoma: Interestingly, SKBR3 and AU565, representing a subgroup of HER2+ tumors which is predicted to be sensitive to ATRA due to co-amplification of the RARA and ERBB2 loci (Paroni et al, 2012), are the only ER−/HER2+ cell lines present in group A. Similarly, HCC-1599 and MDA-MB157 are the only Basal cell lines in groups A and B, respectively.