A 51-year-old female underwent resection of two synchronous liver tumours, a hepatocellular carcinoma and an adenoma. DNA analysis revealed allele loss on chromosome 17 (17p13, near the locus of p53 tumour suppressor gene) in the hepatocellular carcinoma but not in the adenoma. This finding may support the view that loss of p53 tumour suppressor gene is associated with tumour progression.