the situation of drug-resistant tumors. Signs and symptoms Vaginal bleeding is a common symptom of gestational choriocarcinoma. In the event the gestational choriocarcinoma has already spread to other parts of the body, bleeding events in other organs may be the first symptom. If the choriocarcinoma has metastasized to the lungs, one of the most common organs of metastasis, then symptoms may include abnormally quick breathing, coughing, and chest pain. However, it is also possible for there to be none of these symptoms and only a difference in biomarkers in an individual instead. Uterine enlargement as seen in an ultrasound can be a presenting sign of gestational choriocarcinoma. Transvaginal ultrasounds may also be used in screening for the disease, with the positron emission tomography (PET) scan, computed tomography (CT), and magnetic resonance imaging (MRI) in locations such as the abdomen, pelvis, and brain being other imaging options. Chest x-rays may also be used to see if gestational choriocarcinoma has potentially spread to the lungs. Human chorionic gonadotropin is a hormone produced by the trophoblast and can be measured in both urine and blood. Another option of measuring this biomarker level is through lumbar puncture, which can show fluid-to-serum ratio of human chorionic gonadotropic and reflect whether the disease has potentially spread to the central nervous system. Elevated or rising human chorionic gonadotropin can be a sign of gestational choriocarcinoma, though it is also used as a biomarker in other types of gestational trophoblastic diseases (GTD). It is useful not only for diagnosis but also for monitoring disease progression, treatment response, and potential of recurring gestational choriocarcinoma. Causes Gestational choriocarcinoma (GC) is the most aggressive form of trophoblastic tumor; it most commonly arises from certain fertilization defects, such as molar pregnancy, which results in increased level of growth factors and uncontrolled proliferation of trophoblasts in the uterus. Statistics from clinical cases have shown that GC is associated with any pregnancy events, with 50% of GC arise from hydatidiform moles, 25% from gestation, and 25% from abortion or tubal pregnancy. Risk factors The exact underlying causes for this disease are still not fully elucidated, part of the reasons being that this condition is very rare and it is clinically hard to distinguish it from invasive mole, which are other type of trophoblastic tumor that present some similarities as GC. But several risk factors have been reported to have association with gestational choriocarcinoma. Maternal