PDX1 and neoplasm: For passaged PDX1 there was a correlation (r = 0.8, p = 0.003 by Pearson correlation coefficient) between hAAT serum levels and tumor weight (Figure 1D). After accounting for the clustering serum hAAT and tumor weight data from different PDX lines did not show such correlation, which was in line with the highly heterogeneous nature of these tumors (beta = −434.72, p = 0.258) (Figure 1E).