Correlation between Cigarette Smoking and Urine Cotinine Level in Gastric Cancer Patients

Various substances in cigarette smoke including nicotine have been shown to promote/induce cancer cell proliferation. Since cotinine has a longer half life and stability in the blood, it has become the preferred biomarker for cigarette smoking exposure. Seventy-three gastric cancer patients were included in this study. The tumor tissues were stained with H & E for pathological evaluation. The cotinine levels were measured in urine using a competitive ELISA. Tumors were 90% adenocarcinoma with 63% intestinal and 37% diffuse subtypes. Tumors were poorly (45.2%) or moderately differentiated (41.1%) and localized mainly (77%) in the upper part of stomach. The levels of cotinine were significantly different between smoker (283.83 ± 178.10 ng/mL) and non-smoker (39.28 ± 113.34 ng/mL) groups (p < 0.001). However, there is no-significant correlation between tumor characteristics and cotinine level in smoker patients. Cotinine level correlates with smoking in gastric patients, however, correlation with the tumor features has not been observed.