The decreased positivity in the seminiferous tubules with complete preserved spermatogenesis of TGCT patients, compared to non-neoplastic patients, in SALL4, SOX17, RASSF1 and PRSS21 as well as increased CALCA positivity, could be a sign of dysregulated testicular environment due to TGCT or, perhaps, the result of the underlying testicular dysgenesis syndrome in the patients. The gene discussed is SALL4; the disease is testicular germ cell tumor.