In all patients, the serum Gal-3 level was higher in women than in men (13.63 vs. 11.80, p < 0.05), and it showed a statistically significant positive correlation with age (rho = 0.281; p = 0.012), gender (rho = 0.220; p = 0.049), serum peptide C levels (rho = 0.957; p = 0.006), and serum IGF-1 levels (rho = −0.417; p < 0.001, Supplementary Materials Figure S1) in all patients, and for patients without T2D (T2D-), it also showed a statistically significant positive correlation with fasting plasma glucose (rho = −0.406; p = 0.009) (Table 1). The gene discussed is LGALS3; the disease is type 2 diabetes mellitus.