From the Guidelines
Tumors that secrete human chorionic gonadotropin (hCG) include gestational trophoblastic diseases, testicular germ cell tumors (particularly choriocarcinoma and seminoma), and some ovarian germ cell tumors, while alpha-fetoprotein (AFP) is primarily secreted by hepatocellular carcinoma, yolk sac tumors, and some testicular non-seminomatous germ cell tumors (especially embryonal carcinoma and teratoma) 1.
Tumor Markers
The secretion of hCG and AFP by different types of tumors is crucial for diagnosis, monitoring treatment response, and detecting recurrence.
- hCG is secreted by:
- Gestational trophoblastic diseases (including hydatidiform mole and choriocarcinoma)
- Testicular germ cell tumors (particularly choriocarcinoma and seminoma)
- Some ovarian germ cell tumors
- AFP is secreted by:
- Hepatocellular carcinoma
- Yolk sac tumors (endodermal sinus tumors)
- Some testicular non-seminomatous germ cell tumors (especially embryonal carcinoma and teratoma)
Clinical Value
These tumor markers are valuable for:
- Diagnosis of testicular cancer
- Monitoring treatment response
- Detecting recurrence
- Prognostic stratification The biological basis for these secretions relates to the embryonic origins of the tumor cells - hCG is normally produced by placental tissue, while AFP is produced by fetal liver and yolk sac during development 1.
Important Considerations
Elevated levels of these markers in adults typically indicate the presence of these specific malignancies, though some benign conditions can cause mild elevations.
- The half-life of AFP is 5-7 days, and the half-life of hCG is 1-3 days 1.
- Persistent or increasing tumor markers after orchiectomy usually indicate metastatic disease.
- Circulating serum microRNAs (miRNAs) are reported to have a high sensitivity and specificity for testicular cancer diagnosis 1.
From the Research
Tumors that Secrete hCG
- Choriocarcinoma, a subtype of testicular germ cell tumors, secretes human chorionic gonadotropin (hCG) 2, 3, 4
- Testicular germ cell tumors, including non-seminomatous germ cell tumors (NSGCTs), can also secrete hCG 5, 6
- Trophoblastic tumors of placental and germ cell origin secrete hCG 3
Tumors that Secrete AFP
- Yolk sac tumors, a type of non-seminomatous germ cell tumor, secrete alpha-fetoprotein (AFP) 5, 6
- Embryonal carcinoma, another type of non-seminomatous germ cell tumor, can also secrete AFP 6
- Teratoma, a type of germ cell tumor, can secrete AFP in some cases 6
Relationship between hCG and AFP Secretion
- Elevated serum levels of hCG and AFP are used as tumor markers for testicular germ cell tumors 5
- The presence of a small component of choriocarcinoma in a mixed germ cell tumor is typically associated with relatively low-level elevations of serum hCG levels, and is not associated with aggressive disease 6
- Elevated serum levels of hCGbeta are strongly associated with poor prognosis in patients with testicular germ cell tumors 3