AFP and seminoma: As identified by conditional Random Forest modeling with non-endocrine explanatory factors, the most important parameter for discrimination between the hormonal subsets (neutral: n = 157, testicle: n = 72, pituitary: n = 72) was HCG, followed by age at surgery, NSGCT histology, testosterone replacement therapy, LDH, AFP, LVI and percentage of seminoma histology (Supplementary Fig. S7A).