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View the Table of Contents for the October issue of Cancer Epidemiology, Biomarkers & Prevention.
Willett and Hu Page 1757 Kristal and Potter Page 1759
Further exploration, development, and discussion of dietary assessment methods is healthy, even necessary and should lead us toward improved precision. Willett and Hu maintain that the Food Frequency Questionnaire (FFQ) remains a relevant tool in the study of diet and cancer. The authors state their point that biomarkers are complementary to, rather than a replacement for, FFQs in large epidemiologic studies. In a counterpoint immediately following, Kristal and Potter suggest several alternatives to the FFQ, which would be worth investigating. The discussion of this important topic in these two papers suggests some ways forward.
Blackford et al. Page 1799
A four-country study by Blackford et al. examined salivary cotinine as a marker for nicotine intake and addiction among smokers in relation to numbers and types of cigarettes smoked. In the saliva of smokers in Brazil, China, Mexico, and Poland, cotinine concentration increased linearly with cigarettes smoked up to 20 per day, then stabilized as the number of cigarettes exceeded 20 up to 40 cigarettes. On average, smokers of regular cigarettes consumed more cigarettes and had higher cotinine levels than light cigarette smokers. Cotinine concentration per cigarette smoked did not differ between regular and light cigarette smokers. Results suggest a saturation point for daily nicotine intake and minimal or no reduction in nicotine intake by smoking light cigarettes.
Studts et al. Page 1825
Studies of lung cancer screening have suggested that significant numbers of participants quit smoking after screening. However, most studies have relied solely on self-reported smoking behavior, which may be less accurate among participants in lung cancer screening. To assess the validity of self-reported smoking status among participants in a lung cancer screening trial, Studts et al. compared self-reported smoking status against urinary cotinine levels. By eliminating participants who reported concurrent use of nicotine replacement strategies, the analysis revealed sensitivity of 100% and specificity of 95%. In conclusion, self-reported smoking status among participants in a lung cancer screening trial was highly consistent with urinary cotinine test results.
Page 1841
To explore p53 and PCNA expression and polyamine content as biomarkers in skin cancer chemoprevention trials, Einspahr et al. evaluated their expression in early stages of UV-induced squamous cell tumorigenesis. The authors found significant differences in p53 and polyamines in forearms from the sun-damaged group compared to the group with sun-damage plus AK. No significant differences in p53 or polyamines were seen in 3-month biopsies or as a result of sunscreen use, although PCNA in the sun-damaged group not using sunscreen decreased significantly. The authors conclude that p53 expression and polyamines in skin were elevated in early stages of skin tumorigenesis and were not affected by sunscreen, adding validity to their use as biomarkers in skin cancer chemoprevention trials.
Page 1863
Understanding the effect of oral contraceptives (OCs) on risk of breast cancer in BRCA1 or BRCA2 mutation carriers is important because OC use is a common, modifiable practice. Haile et al. studied 497 BRCA1 and 307 BRCA2 mutation carriers, of whom 195 and 128, respectively, had been diagnosed with breast cancer. The authors found no evidence overall that use of OCs for at least one year is associated with breast cancer risk among BRCA1 and BRCA2 mutation carriers before age 50. For BRCA2 mutation carriers, use of OCs may be associated with an increased risk of breast cancer among women who use them for at least five years. Further studies reporting results separately for BRCA1 and BRCA2 mutation carriers are needed to resolve this important issue.