UICC World Cancer Congress 2006

Objective:To investigate the relationship between genetic characteristics and incidence risk of nasopharyngeal carcinoma (NPC) and to explore its inheritance model.

Methods:147 NPC pedigrees reported during 1998-2000 from Sihui cancer registry in Guangdong were interviewed. The questionnaire included questions regarding income levels, housing, domestic pollution, dietary intake, smoking, occupation, individual disease history and familial disease history. The data were analyzed by regressive logistic model using REGTL program of SAGE3.1.

Results:The results showed that Smoking and individual disease history significantly associated with risk of NPC. Comparing heavy smokers (smoking more than 20 cigarettes per day) with non-smokers, the odds ratio of NPC is 5.19 (95% CI: 1.89-14.27). The NPC risk for people with chronic rhititis increased to 8.40 (95%CI: 2.24-31.55) and with other diseases including faucitis, chronic bronchitis, tuberculosis and hepatitis to 2.74 (1.34-5.63) from people without these disease. The prevalence rate of NPC is 2.82% in proband's families comparing to 0.30% in spouse families and a relative risk of NPC is 9.44 (95%CI: 1.23-72.21). The results of complex segregation analysis show mode of Mendelian autosomal dominant inheritance of a major gene that decides susceptibility of NPC provides the best fit to the data. The frequency of the disease allele was 0.1012. The maximum cumulative probability of NPC occurrence among individuals with AA genotype was 28.3% in the age 60 and 78.2% in the age 80. Since mode of Mendelian dominant inheritance is accepted, it suggests a major gene decides the susceptibility of individual to NPC.