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The magnitude and patterns of associations between smoking and risk of nasopharyngeal carcinoma (NPC) in high-incidence regions remain uncertain. Associations with active and passive tobacco smoking were estimated using multivariate logistic regression in a population-based case-control study of 2,530 NPC cases and 2,595 controls in Guangdong and Guangxi, southern China, in 2010-2014. Among men, risk of NPC was significantly higher in current smokers compared with never smokers (odds ratio (OR) = 1.32,95% confidence interval (CI): 1.14,1.53) but not in former smokers (OR = 0.92, 95% CI: 0.73,1.17). Risk increased with smoking intensity (per 10 cigarettes/ day, OR = 1.09, 95% CI: 1.03,1.16), smoking duration (per 10 years, OR = 1.11,95% CI: 1.06,1.16), and cumulative smoking (per10pack-years, OR = 1.08, 95% CI: 1.04,1.12). Risk decreased with later age at smoking initiation (per year, OR = 0.97, 95% CI: 0.96, 0.98) but not greater time since smoking cessation. Exposures to passive smoking during childhood (OR = 1.24, 95% CI: 1.03, 1.48) and from a spouse during adulthood (OR = 1.30, 95% CI: 1.03, 1.63) were independently associated with increased NPC risk in never-smoking men and women, but exposure- response trends were not observed. In conclusion, active and passive tobacco smoking are associated with modestly increased risk of NPC in southern China; risk is highest among long-term smokers. [ABSTRACT FROM AUTHOR]

AIB1, a candidate oncogene in breast cancer, is commonly amplified and overexpressed in several types of human cancers. In this study, expression and amplification of AIB1 in nasopharyngeal carcinoma (NPC) were studied by immunohistochemical analysis and fluorescence in situ hybridization using tissue microarrays, including 80 specimens of NPC and 20 specimens of nonneoplastic nasopharyngeal mucosa. In this NPC cohort, overexpression and amplification of AIB1 was detected in 36 (51%) of 71 and 3 (7%) of 46 NPCs, respectively. Overexpression of AIB1 was observed more frequently in NPCs in late T stages (T3/T4, 24/35 [69%]) than in earlier stages (T1/T2, 12/36 [33%]; P 05). In addition, 18 (72%) of 25 NPCs with lymph node metastasis (N1-3) showed overexpression of AIB1; the frequency was significantly higher than that in NPCs without node metastasis (N0, 18/49 [39%]; P 05). These findings suggest that overexpression of AIB1 in NPCs may be important in the acquisition of an invasive and/or metastatic phenotype. [ABSTRACT FROM AUTHOR]