To identify genes whose expression is specifically associated to gestational trophoblastic diseases the differential display technique was performed. This strategy resulted in the isolation of an EST named UNCDD1 which identified a clone containing a 3315bp insert from HeLa cell line cDNA library. This cDNA encodes a protein called GTT1/StarD7 of 295 aminoacids that shows 49% of similarity with the phosphatidylcholine transfer protein and has a START domain. Northern blot assays performed with normal, benign and malignant gestational trophoblastic samples revealed a 3.5kb transcript exclusively expressed in the JEG-3 choriocarcinoma cell line. However, semiquantitative RT-PCR analysis carried out with the same samples demonstrated GTT1/StarD7 expression throughout all of them but the expression level was more than 3 times higher in JEG-3 cell line. Semiquantitative RT-PCR assays performed in diverse human tumour cell lines revealed GTT1/StarD7 expression in all of them with the highest levels detected in JEG-3, JAR, HT-29 and HepG2 cells. Finally, an increase of 100% in GTT1/StarD7 expression was observed when dexamethasone was added to JEG-3, HT-29 and HepG2 cell cultures. In conclusion , the high GTT1/StarD7 expression profile in JEG-3 cells, its lipids binding domain and dexametasone regulation suggest that GTT1/StarD7 may play an important role in the phospholipid-mediated signaling of gestational trophoblastic tumours cellular events.