O6-Alkylguanines, Dietary N-Nitroso Compounds, and Their Precursors in Gastric Cancer

• Published in: Nutrition and cancer 2001-01, Vol.39 (1), p.42-49
• Main Authors: Palli, Domenico, Saieva, Calogero, Coppi, Claudio, Del Giudice, Giuseppe, Magagnotti, Cinzia, Nesi, Gabriella, Orsi, Federica, Airoldi, Luisa
• Format: Article
• Language: English
• Subjects: Aged; Antibodies, Bacterial - blood; Biological and medical sciences; Carcinogenesis, carcinogens and anticarcinogens; Diet; Dimethylamines - analysis; Dimethylnitrosamine - analysis; DNA Adducts - analysis; Female; Food Analysis; Foods and miscellaneous; Gas Chromatography-Mass Spectrometry; Gastric Juice - chemistry; Gastric Mucosa - chemistry; Gastric Mucosa - pathology; Gastroenterology. Liver. Pancreas. Abdomen; Guanine - analysis; Helicobacter pylori - immunology; Helicobacter pylori - pathogenicity; Humans; Male; Medical sciences; Middle Aged; Nitroso Compounds - adverse effects; Nitroso Compounds - analysis; Stomach Neoplasms - chemistry; Stomach Neoplasms - etiology; Stomach. Duodenum. Small intestine. Colon. Rectum. Anus; Surveys and Questionnaires; Tumors
• ISSN: 0163-5581; 1532-7914
• DOI: 10.1207/S15327914nc391_6

Several N-nitroso compounds, present in foods and beverages or formed in the stomach from their precursors, act as alkylating agents. By using a highly reliable technique (high-resolution gas chromatography-mass spectrometry with negative-ion chemical ionization and selected ion recording), we measured a series of specific O 6 -alkylguanines in snap-frozen paired stomach tissue samples (tumor and noninvolved mucosa) obtained at surgery from 24 gastric cancer patients identified in Florence, Italy. Samples of noninvolved mucosa had higher levels of total O 6 -alkylguanines and more frequently detectable levels (54%) than tumor samples (29.2%). O 6 -propylguanine and O 6 -methylguanine were the single adducts most frequently detected in noninvolved mucosa and tumor tissue, respectively. Tumor samples showed higher levels of total O 6 -alkylguanines in female patients (p = 0.03) and among those with a diffuse histological type (p = 0.06) or seronegative for Helicobacter pylori CagA antibodies (p = 0.06). Mean dietary nitrate intake was significantly higher in patients with detectable levels of adducts in tumor samples (p = 0.03). Estimated intakes of dimethylamine and N-nitrosodimethylamine correlated with total levels of O 6 -alkylguanines in noninvolved gastric mucosa. These findings, although based on a small series of cases, support a role for N-nitroso compounds from dietary sources in the etiology of gastric cancer.