DNA ploidy pattern and tumour spread in gastric cancer

The DNA ploidy pattern of gastric cancer was studied in 58 patients to investigate the heterogeneity between primary tumour and metastases. In both primary tumours and lymph node metastases, diploid patterns accounted for 33 per cent, whereas all liver metastases were aneuploid. The percentage of polyploid cells was higher in the liver metastases than in primary tumours and lymph node metastases. When the heterogeneity of DNA ploidy pattern between primary tumour and metastasis was evaluated, diploid tumours had a significantly lower rate of lymph node metastasis heterogeneity than aneuploid tumours. When the DNA ploidy pattern and survival were evaluated, the patients who had a diploid pattern in both primary tumour and metastasis had a significantly higher survival rate than the patients who had an aneuploid pattern in the primary tumour and metastasis (57 per cent versus 26 per cent at 5 years). These data suggest that cell heterogeneity is a common phenomenon in gastric cancer, and this may be important in the evolution of the disease. Furthermore, the role of the DNA ploidy pattern as a prognostic factor is emphasized.