Soluble Fas level and cancer mortality: findings from a nested case-control study within a large-scale prospective study

Soluble Fas (sFas) is known to play an important role in the development of cancers of various sites. To confirm whether or not the serum sFas level can be a predictor of cancer, we conducted a nested case-control study within a large-scale population-based cohort study in Japan. Serum samples were collected from 39,242 participants (13,839 men and 25,403 women) at baseline, all of whom were followed until 1997 for mortality and until 1994 for cancer incidence. Three controls were randomly selected and matched to each cancer case for gender, age and residential area. Serum values of sFas were measured by enzyme-linked immuno-adsorbent assay, using commercially available kits. The odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated using conditional logistic models, based on 798 total cancer mortality cases and their 2,353 matched controls. The risk of total cancer mortality was increased according to sFas levels, and the OR of the highest quartile compared with that of the lowest was 1.81 (95% CI; 1.40-2.34) after adjusting for smoking and drinking status, and body mass index. This positive association remained unaltered when cases were divided into 2 groups according to the observation period. Our results suggest that serum sFas has a possibility to detect people at high risk for cancer prior to diagnosis, since it increased before cancer diagnosis in those apparently healthy people.