Workshop report; Subgroup report: Stomach cancer; Subgroup report: Lymphohaematopoietic neoplasms; Subgroup report: Head and neck cancer; GENERAL CONSIDERATIONS; Metabolic and biochemical issues in the molecular epidemiology of cancer; Exposure biomarkers for the study of toxicological impact on carcinogenic processes; Biomarkers of inherited susceptibility and cancer; Toxicological considerations in the application and interpretation of susceptibility biomarkers in epidemiological studies; Toxicokinetic genetics: an approach to gene-environment and gene-gene interactions in complex metabolic pathways; GENETICS ISSUES; Mechanistic insights from biomarker studies: somatic mutations and rodent/human comparisons following exposure to a potential carcinogen; Cytogenetic biomarkers; Epidemiologic evaluation of cytogenetic biomarkers as potential surrogate endpoints for cancer; Implications of molecular epidemiology results on DNA adducts, their repair and mutations for mechanisms of human cancer; Toxicologic considerations in the application and interpretation of DNA adducts in epidemiology studies; TP53 mutation spectra and load: a tool for generating hypotheses on the aetiology of cancer; Identification and characterization of potential human carcinogens using B6.129tm1 Trp53 heterozygous null mine and loss of heterozygosity at the Trp53 locus; Multiple primary cancers as clues of environmental and heritable causes of cancer and mechanisms of carcinogenesis; TARGET ORGANS; The biologic model of gastric carcinogenesis; Epidemiology of gastric cancer; Genetic pathway of two types of gastric cancer; Biological models for leukaemia and lymphoma; Causal models of leukaemia and lymphoma; Mechanistic considerations in the molecular epidemiology of head and neck cancer; Future studies and design considerations; Design and analysis issues in studies of gene-environment interactions; Emerging biomarker technologies