The VEGFR-2 data was collected and preprocessed as described in Section 2.1.2. We divided the preprocessed dataset, which consisted of 4,770 substances represented by 16 types of molecular features, into a training set of 4,115 substances and an external validation set of 655 substances, corresponding to proportions of 86% and 14%, respectively. According to the meta-analysis result, the dataset using RDKit fingerprint with maxPath = 7 (RDK7) gave the highest mean of R 2 of 0.641 (Fig. ), which was significantly higher than the others (p < 0.01) based on Wilcoxon signed-rank tests (Fig. ).