p53 gene expression in relation to indoor exposure to unvented coal smoke in Xuan Wei, China

Lung cancer mortality rates in Xuan Wei County which are among the highest in China, have previously been associated with exposure to indoor emissions from burning smoky coal. To determine if this association is stronger amon g lung cancer patients with abnormal expression of p53, we performed a popu lation-based case-control study. Ninety-seven newly diagnosed lung cancer p atients and 97 controls, individually matched by age, sex, and home fuel ty pe were enrolled. We used immunocytochemical methods to assess p53 protein accumulation in exfoliated tumor cells isolated from sputum samples. As exp ected the amount of lifetime smoky coal use was associated with an overall increase in lung cancer risk. Compared with subjects who used bs than 130 t ons of smoky coal during their lifetime, the odds ratios (OR)for lung cance r were 1.48 (95% confidence interval [CI] 0.73 to 3.02)for subjects exposed to 130 to 240 tons, and 3.21 (95% CI, 1.23 to 9.03) for subjects who used more than 240 tons of smoky coal (P for trend 0.01). The effect was due alm ost exclusively to the pattern in women, almost all of whom were nonsmokers . Further, among highly exposed women, the association was substantially la rger and achieved statistical significance only among patients with sputum samples that were positive for p53 overexpression (OR, 18.72; 95% CI, 1.77 to 383.38 vs OR 4.80; 95% CI, 0.66 to 43.87 for p53-negative cases). This s tudy suggests that exposure to the combustion products of smoky coal in Xua n Wei is more strongly associated with women who have lung cancer accompani ed by p53 protein overexpression in exfoliated tumor cells.