APOE and polycystic ovary syndrome: Figure 2B displays the tenfold cross-validation results, where the two dashed lines represent the minimum error criterion (λ.min) and the one–standard error criterion (λ.1se). Under the λ.min criterion, nine variables with nonzero coefficients—AD, T, AMH, TG, DHEAS, ApoE, Lp(a), FSH, and age—were finally selected as key features strongly associated with the diagnosis of polycystic ovary syndrome (PCOS) (Figure 2D).