Functional DNA Repair Assays for Lung Cancer Risk: Prospective Analysis
1. Create immortalized lymphoblastoid cell lines (LCLs) from cryopreserved B lymphocytes derived from PLCO vials that were step-frozen in DMSO.
2. Perform functional or related assays on 200 LCLs, comparing cases and controls for:
a. Single strand DNA break damage as an indicator of capacity to handle oxidative DNA damage (Comet Assay). Lung cancer cases will have higher levels of DNA damage than controls.
b. Capacity to repair bulky DNA adducts (Host cell reactivation (HCR) assay using benzo(a)pyrene diol epoxide (BPDE) as the test mutagen). Lung cancer cases will have a lower capacity to repair bulky adducts compared to controls.
c. Sensitivity to inducers of double strand DNA breaks (mutagen sensitivity assay for unrepaired chromatid breaks after bleomycin exposure). Lung cancer cases will have increased frequencies of chromatid breaks compared to controls.
3. Follow-on study: Re-sequence for DNA repair pathway gene variants among the 40 persons occupying the extremes in the distribution tails for each of the 3 assays. This aim is designed to discover the gene variants contributing to the extremes in the phenotypes measured. Because cryopreserved lymphocytes were collected before cancer onset from more than 50,000 participants in the PLCO Trial, PLCO investigators are in a unique position to carry out these studies. In addition, these cell lines will be a continuing resource, growing increasingly valuable with further characterization and will provide an unlimited source of DNA.
Neil Caporaso (NCI, DCEG)
Michael Hauptmann (NCI, DCEG)
Richard Hayes (NCI, DCEG)
Wen-Yi Huang (NCI, DCEG)
Irene Jones (Lawrence Livermore Nat'l Laboratory)
Margaret Spitz (UT M.D. Anderson Cancer Center (UTMDACC))
Qingyi Wei (UTMDACC)
Douglas Reding (Marshfield Clinic)
Alice Sigurdson (NCI, DCEG)
Jeffery Struewing (LPG, CCR, NCI, NIH)
Xifeng Wu (UTMDACC)
Prospective analysis of DNA damage and repair markers of lung cancer risk from the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.
Sigurdson AJ, Jones IM, Wei Q, Wu X, Spitz MR, Stram DA, Gross MD, Huang WY, Wang LE, Gu J, Thomas CB, Reding DJ, Hayes RB, Caporaso NE
Carcinogenesis. 2011 Jan; Volume 32 (Issue 1): Pages 69-73 PUBMED