have no effect of the DNA repair efficiency of XPD (Lunn et al. 2000; Hemminki et al. 2001; Laine´ et al. 2007). In addition, results regarding the role of this polymorphism in carcinogenesis are quite inconsis- tent, showing an association between the A variant genotype (encoding Asn) either with decreased (Lovatt et al. 2005; He et al. 2008) or, more commonly, with increased (Hu et al. 2004; Wang et al. 2008; Gangwar et al. 2009) risk of cancer development. Data regarding the Arg156Arg poly- morphism are sparse and also inconsistent: the presence of the A allele was correlated with both increased (Harth et al. 2008) and with decreased (Lovatt et al. 2005) cancer risk. We think it is likely that these polymorphisms do not play a ‘universal’ role in cancer pathogenesis. Our results showing that

Acknowledgments This work was supported by the Polish Ministry of Education and Science grant PBZ-MEiN-9/2/2006 (K143/P01/2007/1)

References

Afanas’ev I (2009) Superoxide and nitric oxide in senescence and aging. Front Biosci 14:3899–3912

and aging. Front Biosci

:

–

Andreassi MG (

) DNA damage, vascular senescence and atherosclerosis. J Mol Med

:

–

Andressoo JO, Hoeijmakers JH (

) Transcription-coupled repair and premature ageing. Mutat Res

:

–

Andressoo JO, Weeda G, de Wit J, Mitchell JR, Beems RB, van Steeg H, van der Horst GT, Hoeijmakers JH (

) An Xpb mouse model for combined xeroderma pigmen- tosum and cockayne syndrome reveals progeroid features upon further attenuation of DNA repair. Mol Cell Biol

:

–

Arking DE, Krebsova A, Macek M Sr, Macek M Jr, Arking A, Mian IS, Fried L, Hamosh A, Dey S, M

ntosh I, Dietz HC (

) Association of human aging with a functional variant of klotho. Proc Natl Acad Sci USA

:

–

Blagosklonny MV (

) Aging: ROS or TOR. Cell Cycle

:

–

Blander G, de Oliveira RM, Conboy CM, Haigis M, Guarente L (

) Superoxide dismutase

knock-down induces senescence in human fibroblasts. J Biol Chem

:

–

Bonafe` M, Olivieri F (

) Genetic polymorphism in long- lived people: cues for the presence of an insulin/IGF- pathway-dependent network affecting human longevity. Mol Cell Endocrinol

:

–

Brewster AM, Alberg AJ, Strickland PT, Hoffman SC, Hel- zlsouer K (

) XPD polymorphism and risk of sub- sequent cancer in individuals with nonmelanoma skin cancer. Cancer Epidemiol Biomarkers Prev

:

–

Burhans WC, Weinberger M (

) DNA replication stress, genome instability and aging. Nucleic Acids Res

:

–

Coin F, Marinoni JC, Rodolfo C, Fribourg S, Pedrini AM, Egly JM (

) Mutations in the XPD helicase gene result in XP and TTD phenotypes, preventing interaction between XPD and the p

subunit of TFIIH. Nat Genet

:

–

Crews DE (

) Senescence, aging, and disease. J Physiol Anthropol

:

–

Cullinane C, Weber CA, Dianov G, Bohr VA (

) Resto- ration of preferential and strand specific gene repair in group

Chinese hamster ovary mutants (UV

) by the XPD (ERCC

) gene. Carcinogenesis

:

–

de Boer J, Andressoo JO, de Wit J, Huijmans J, Beems RB, van Steeg H, Weeda G, van der Horst GT, van Leeuwen W, Themmen AP, Meradji M, Hoeijmakers JH (

) Pre- mature aging in mice deficient in DNA repair and tran- scription. Science

:

–

Di Massimo C, Scarpelli P, Di Lorenzo N, Caimi G, di Orio F, Ciancarelli MG (

) Impaired plasma nitric oxide availability and extracellular superoxide dismutase activ- ity in healthy humans with advancing age. Life Sci

:

–

D

tefano PS, Curtis R, Geddes BJ (

) Insulin resistance, glycemic control and adiposity: key determinants of healthy lifespan. Curr Alzheimer Res

:

–

Ehrlich R, Harris A, Kheradiya NS, Winston DM, Ciulla TA, Wirostko B (

) Age-related macular degeneration and the aging eye. Clin Interv Aging

:

–

Evans E, Moggs JG, Hwang JR, Egly JM, Wood RD (

) Mechanism of open complex and dual incision formation by human nucleotide excision repair factors. EMBO J

:

–

Fan L, Fuss JO, Cheng QJ, Arvai AS, Hammel M, Roberts VA, Cooper PK, Tainer JA (

) XPD helicase structures and activities: insights into the cancer and aging phenotypes from XPD mutations. Cell

:

–

Finch CE, Ruvkun G (

) The genetics of aging. Annu Rev Genomics Hum Genet

:

–

Flachsbart F, Caliebe A, Kleindorp R, Blanche´ H, von Eller- Eberstein H, Nikolaus S, Schreiber S, Nebel A (

) Association of FOXO

A variation with human longevity

USA

:

–

Frederick GD, Amirkhan RH, Schultz RA, Friedberg EC (

) Structural and mutational analysis of the xero- derma pigmentosum group D (XPD) gene. Hum Mol Genet

:

–

Gangwar R, Ahirwar D, Mandhani A, Mittal RD (

) Influence of XPD and APE

DNA repair gene polymor- phism on bladder cancer susceptibility in north India. Urology

:

–

Go¨zu¨kara EM, Parris CN, Weber CA, Salazar EP, Seidman MM, Watkins JF, Prakash L, Kraemer KH (

) The human DNA repair gene, ERCC

(XPD), corrects ultra- violet hypersensitivity and ultraviolet hypermutability of a shuttle vector replicated in xeroderma pigmentosum group D cells. Cancer Res

:

–

Hari R, Burde V, Arking R (

) Immunological confirmation of elevated levels of C

n superoxide dismutase protein in an artificially selected long-lived strain of Drosophila melanogaster. Exp Gerontol

:

–

Harth V, Schafer M, Abel J, Maintz L, Neuhaus T, Besuden M, Primke R, Wilkesmann A, Thier R, Vetter H, Ko YD, Bruning T, Bolt HM, Ickstadt K (

) Head and neck squamous-cell cancer and its association with polymor- phic enzymes of xenobiotic metabolism and repair. J Toxicol Environ Health A

:

–

Hayflick L (

) Biological aging is no longer an unsolved problem. Ann N Y Acad Sci

:

–

He X, Ye F, Zhang J, Cheng Q, Shen J, Chen H (

) Sus- ceptibility of XRCC

, XPD, and XPG genetic variants to cervical carcinoma. Pathobiology

:

–

Hemminki K, Xu G, Angelini S, Snellman E, Jansen CT, Lambert B, Hou SM (

) XPD exon

and

poly- morphisms and DNA repair in human skin in situ. Car- cinogenesis

:

–

Herskind AM, M

ue M, Holm NV, Sorensen TI, Harvard B, Vaupel JW (