Recent studies have revealed that endothelin-1 (ET-1) may be produced by human cancer cell lines and have suggested that in vivo the peptide might play a modulatory role in the growth of stromal cells surrounding tumor cells and/or in the growth of the cancer cells themselves, through paracrine or autocrine mechanisms. Therefore, we investigated whether ET-1 and ET receptors could be expressed in the human gastric cancer cell line HGT-1. By applying the reverse transcriptase polymerase chain reaction (RT-PCR) to total RNA extracted from the cells, using oligonucleotides synthesized from the sequence of the prepro-ET-1 mRNA, we have amplified a cDNA at the expected size (453 bp), which hybridized with a labeled ET-1-specific probe. In addition, RT-PCR was carried out to test whether HGT-1 cells expressed mRNA for ETA and/or ETB receptor subtypes. The amplified products of cDNA were at the size predicted for the ETA receptor (368 bp), whereas no ETB receptor mRNA could be detected.