Later, Rodrigo-Torres et al. found that ductular reaction cells express Hnf1β in human liver cirrhosis; thus, they used Hnf1βCreER/R26RYfp/LacZ mice, which carry the yellow fluorescent protein (YFP) gene downstream of Hnf1β-cre, to track HNF1+ biliary duct cells. Here, HNF1B is linked to cirrhosis of liver.