Using qRT-PCR normalized to ribosomal 18S rRNA, the xenograft OE19 tumour cells showed a ∼10 fold reduction in HER2 expression compared to the parental OE19 cells (p < 0.00005) and a ∼20 fold increase in mRNA levels compared to the cell line Het1A (p < 0.00005) (Supplementary Figure 6). The gene discussed is ERBB2; the disease is neoplasm.