GDF15 and neoplasm: We observed a statistically significantly positive correlation between MIC-1 expression in tumor tissues (0.077 ± 0.013) and matched serum samples (2085.9 ± 1477.6 pg/mL) from these patients (r = 0.569, P < 0.001; Figure 1b), and the serum MIC-1 level in these patients with upregulated expression of MIC-1 in tumor tissues (n = 51) was significantly higher than that with down-regulated expression of MIC-1 (n = 13) (P =0.004; Figure 1c).