The authors of this study used miRNA array platforms and quantitative reverse transcriptase–PCR to measure miRNA levels in wild type versus Ahr-null mice, in dioxin-sensitive Long-Evans (L-E; Turku/AB) rats versus dioxin-resistant Han/Wistar (H/W; Kuopio) rats and in rat 5L and mouse Hepa-1 hepatoma cells in culture. The gene discussed is AHR; the disease is hepatocellular carcinoma.