AIM: To investigate the role of DCC gene inactivation in the development and progression of gastric cancer. METHODS: Loss of heterozygosity and loss of expression of the DCC gene was studied in 51 surgical specimens of gastric cancer using detection based on polymerase chain reaction. RESULTS: Loss of heterozygosity was found in 35.3% (18 of 51) of specimens and was detected more often in stage III and IV (50%) than in stage I and II cancers (14.3%) (p < 0.05). Occurrence of loss of heterozygosity was not correlated with histological type, tumour size, depth of invasion, or lymph node metastasis. Loss of expression was found in 49% of cases (25 of 51). Loss of expression was not significantly correlated with any clinicopathological variable. CONCLUSIONS: Loss of heterozygosity and loss of expression of the DCC gene are often encountered in gastric cancer. Loss of heterozygosity of the DCC gene is a late event and associated with malignant progression.