[Elevation of β-subunit of human chorionic gonadotropin in urological patients-not always a germ cell tumor]

The determination of the β‑subunit of human chorionic gonadotropin (HCG) is routinely used in urology as a tumor marker for germ cell tumors. This review highlights the differential diagnoses of β‑HCG elevation unrelated to germ cell cancer.

Causes of elevated β‑HCG levels include, among others, measurement errors due to the homology between luteinizing hormone (LH) and β‑HCG or in cases of immunoglobulin A (IgA) deficiency syndrome, reduced excretion in renal insufficiency, iatrogenic causes (e.g., substitution therapy, during androgen deprivation therapy), or hormonal disorders. Additionally, β‑HCG is produced autocrinely by 10-30% of all malignant nongerm cell tumors. In urothelial carcinoma, literature reports show positive detection in 30-76% of serum samples, 35-73% of urine samples, and approximately 35% in immunohistochemical analyses. Apart from testicular tumors, β‑HCG currently has no established role in routine tumor diagnostics. The expression pattern in the metastatic stage of urothelial carcinoma correlates with therapeutic response.

In cases of implausible β‑HCG elevation during testicular tumor diagnostics or follow-up, one must consider the numerous differential diagnoses. In the future, β‑HCG could become a promising marker for monitoring hormone-expressing, metastatic urothelial carcinoma.