Gestational trophoblastic neoplasia comprises a unique group of human neoplastic diseases that derive from fetal trophoblastic tissues and represent semiallografts in patients. This group is composed of choriocarcinoma, placental-site trophoblastic tumour, and epithelioid trophoblastic tumour, and many forms are derived from the precursor lesions, hydatidiform moles. Although most patients with gestational trophoblastic neoplasia are cured by chemotherapy and tumour resection, some patients suffer from metastatic diseases that are refractory to conventional chemotherapy. Therefore, new therapeutic regimens are needed to reduce the toxic effects associated with current chemotherapy and to salvage the occasional non-operable patients with recurrent and chemoresistant disease. Until the fundamental biology of gestational trophoblastic neoplasia becomes more clearly understood, development of a new treatment will remain empirical. This review will briefly summarise the recent advances in understanding the molecular aetiology of this group of diseases and highlight the molecules that can be potentially used for therapeutic targets to treat metastatic gestational trophoblastic neoplasia.