NOXO1 and neoplasm: We found that the mean mRNA expression ratios of NOX1 or its accessory genes in HT-29 cells (normalized to β-actin) were ≈15,000 (×10−6) for NOX1; ≈20,000 (×10−6) for NOXO1; and 1100 (×10−6) for NOXA1 (Table 1); these experiments, in conjunction with our previous study (40), strongly suggest that among human tumor cells lines, NOX1 is most frequently expressed in those originating from the colon (31).