| Abstract: | 本計畫第一年以/sup 32/P-postlabeling assay分析比較高空氣汙染地區之肺癌病患之肺組織中PAH-DNA adducts的含量和種類與低汙染地區之肺癌患者DNA adducts有何不同以提出空氣汙染和肺癌發生的相關性。首先必須先確定肺癌患者之肺組織中DNA adducts含量和罹患肺癌之危險性具有正相關性。因此本計畫先比較73位肺癌患者和33位非癌症患者之肺組織中DNA adduct的含量是否有差異結果發現肺癌患者之DNA adduct平均含量為49.58.plmin.33.39 adducts/10/sup 8/ nucleotides,而非癌症患者僅有18.00.plmin.15.33 adducts/10/sup 8/ nucleotides,其間有非常顯著的差異(p<0.001)。而這其間的差異經Multivariate linear regression統計分析結果顯示,和年齡、性別、抽煙狀態以及參與代謝主要空氣汙染物---多環芳香烴之CYP1A1和GSTM1的基因多形性都沒有相關性。再經過Multivariate logistic regression統計分析發現僅有年齡和DNA adduct含量能做為評估發生肺癌的危險因子。DNA adduct高於48.66 adducts/10/sup 8/ nucleotides者發生肺癌的危險性是低DNA adduct含量者的25.2倍(p=0.003)。而年齡僅有1.1倍(p=0.02)。因此肺組織中的DNA adduct含量可做為罹患肺癌的危險生物指標。另外,本計畫已完成分析低空氣汙染地區包括新竹、苗栗、台中和高空氣汙染地區包括雲林、嘉義、台南的男、女性肺癌死亡率在高、低空氣汙染地區之間都有統計上的差異。在高汙染地區的不抽煙之肺癌患者,具有較高DNA adduct的樣本數較低汙染地區為多,但由於肺癌患者在高汙染地區的樣本較少,因此在現階段分析的樣本結果在統計上沒有差異(p=0.092)。另外本計畫也成功的化學合成出含有1.4%之Benzo[a]pyrene(BaP)代謝活化物---BPDE-calf thymus DNA adducts,並發展出BaP-DNA adduct的Polyclonal antibody。其50% inhibition value 1.6 fmole。分析DNA adduct的最低值為3.2 adducts/10/sup 8/ nucleotides。其敏感性較過去其他學者所發展出的抗體為高。因此將來分析肺組織之DNA adducts可用ELISA方法分析,較/sup 32/ P-postlabeling assay所得知結果,更能準確定出PAH-DNA adducts之含量。
In the first year's project, we compare the DNA adduct levels between lung cancer and non-cancer control to confirm the DNA adduct level in lung target tissue may be used as a risk biomarker of lung cancer. This result is important for the determination of the relationship between the DNA adduct level and lung cancer incidence. The DNA adduct levels of non-tumorous lung tissues resected from 73 lung cancer patients and 33 non-cancer controls were evaluated by /sup 32/P-postlabeling assay. Our data showed that DNA adduct levels of lung cancer patients were significantly higher than those of non-cancer controls (p<0.001). Multivariate linear regression showing the difference in DNA adduct level between cases and controls was independent among varieties including age, gender, smoking status, polymorphisms of CYP1A1 and GSTM1. Multivariate logistic regression indicated that person with high DNA adduct level (>48.7 adducts/10/sup 8/ nucleotides) had 25.2-fold of risk for lung cancer comparing with person with low DNA adduct level (<48.7 adducts/10/sup 8/ nucleotides). This result suggests that DNA adduct level in lung target tissue may be used as a risk biomarker of lung cancer. The specific aim of this project is to explore the relationships between environmental exposure and lung cancer incidence. Thus, we also compare the DNA adduct levels of non-smoking lung cancer patients living either in a high pollution area including Hsinchu, Miaoli, and Taichung, or in low pollution area including Yunlin, chiayi, and Tainan. No significantly different was observed in DNA adduct levels of lung cancer patients between high and low pollution area, because of relatively lower patient number in high pollution area comparing to the those in low pollution area. In this year's project, the polyclonal antibody of BaP-DNA adduct has been developed by our laboratory. The 50% inhibition value and detection limit of DNA adduct level were 1.6 fmole and 3.2 adducts/10/sup 8/ nucleotides, respectively. The detection sensitivity of BaP-DNA adduct levels was higher than antibodies developed by other laboratories. The ELISA method to detect the PAH-DNA adduct in lung tissue will be performed in following experiments in this project. |
