BUB1B and cholangiocarcinoma: For the distribution of H-scores of BubR1, we set a cutoff value to separate low and high expression levels of BubR1 using the median H-score of 140 calculated from 189 CCA tissues, while 24 normal bile ducts (NBDs) showed a significantly lower median H-score of 100 (p < 0.001; Figure 2D).