Background: Screening of cDNA arrays of the IMAGE library identified human zFOC1 as a differentially expressed cDNA that was upregulated in KATO III gastric cancer cells following stimulation with the gastric pathogen Helicobacter pylori. Aims: To determine the expression of zFOC1 in gastric mucosa with and without H pylori infection and in patients with gastric cancer. Results: zFOC1 is localised on chromosome 12q24.3 and encodes a zinc finger protein. Expression studies in human H pylori infected and uninfected gastric biopsies, gastric tumours, and gastric cancer cell lines revealed that zFOC1 gene transcripts are significantly higher in gastric cancer than in non-cancerous gastric tissues. Conclusions: The zFOC1 gene appears to be a tumour marker associated with gastric cancer.