What substance is primarily secreted by choriocarcinomas?

Choriocarcinomas are a type of gestational trophoblastic neoplasm that originates from the placenta and is characterized by the malignant transformation of trophoblast cells. One of the hallmark features of choriocarcinomas is their production of beta-human chorionic gonadotropin (β-hCG). This hormone is produced during pregnancy and is typically detectable in the blood and urine of pregnant women. In the case of choriocarcinoma, the levels of β-hCG can be significantly elevated, which is often used as a biomarker for diagnosis and monitoring of the disease.

The rationale for identifying β-hCG as the primary substance secreted by choriocarcinomas lies in the differentiation of the tumor from other types of tumors and its relationship to placental tissue. Tracking levels of beta-hCG can provide insight into the tumor's activity and response to treatment, making it not only a diagnostic marker but also a tool for ongoing management.

In contrast, the substances listed in the other choices do not play a significant role in the pathology of choriocarcinomas. Alpha-fetoprotein is primarily associated with hepatocellular carcinoma and certain germ cell tumors, luteinizing hormone is involved in regulating the menstrual cycle