[1] Klein G, Klein E. Epstein-Barr virus and human lymphomas. The Lymphomas. Eds G. Canellos, T. Lister, J. Sklar. Philadelphia: W. B. Saunders Company, 1998: 63-73.

[2] Glucksmann A. Cell deaths in normal vertebrate ontogeny. Biol Rev Camb Philos Soc. 1951;26(1):59-86.

[3] Butenko ZA. Apoptosis regulating oncogenes in the mechanisms of lymphoma and carcinogenesis. Eksperimentalnaya Onkologiya. 1995; 17(3): 165-171

[4] Butenko ZA. Programmed cell death in malignant lymphomas. Dopovidi Nats Akad Nauk Ukrainy. 1999;(1):185-8.

[5] Khanson KP. Apoptosis: current status of the problem. Izv Akad Nauk. Ser Biol. 1998;(2):134-41.

[6] Wilson W, Chabner BA. Principles of chemotherapy for lymphomas. The Lymphomas. Eds G. Canellos, T. Lister, J. Sklar. Philadelphia: W. B. Saunders Company,1998:235-46.

[7] Teodoro JG, Branton PE. Regulation of apoptosis by viral gene products. J Virol. 1997;71(3):1739-46.

[8] Messam CA, Pittman RN. Asynchrony and commitment to die during apoptosis. Exp Cell Res. 1998;238(2):389-98.

[9] Tschopp J, Irmler M, Thome M. Inhibition of fas death signals by FLIPs. Curr Opin Immunol. 1998;10(5):552-8.

[10] Fil'chenkov AA, Stoika RS. Apoptosis and cancer. Kyiv, Morion, 1999; 184 p.

[11] Hengartner MO. Programmed cell death in the nematode C. elegans. Recent Prog Horm Res. 1999;54:213-22.

[12] Wu D, Chen PJ, Chen S, Hu Y, Nu?ez G, Ellis RE. C. elegans MAC-1, an essential member of the AAA family of ATPases, can bind CED-4 and prevent cell death. Development. 1999;126(9):2021-31.

[13] Yuan J, Shaham S, Ledoux S, Ellis HM, Horvitz HR. The C. elegans cell death gene ced-3 encodes a protein similar to mammalian interleukin-1 beta-converting enzyme. Cell. 1993;75(4):641-52.

[14] Zou H, Henzel WJ, Liu X, Lutschg A, Wang X. Apaf-1, a human protein homologous to C. elegans CED-4, participates in cytochrome c-dependent activation of caspase-3. Cell. 1997;90(3):405-13.

[15] Van de Craen M, Van Loo G, Pype S, Van Criekinge W, Van den brande I, Molemans F, Fiers W, Declercq W, Vandenabeele P. Identification of a new caspase homologue: caspase-14. Cell Death Differ. 1998;5(10):838-46.

[16] Thornberry NA, Lazebnik Y. Caspases: enemies within. Science. 1998;281(5381):1312-6.

[17] Enari M, Sakahira H, Yokoyama H, Okawa K, Iwamatsu A, Nagata S. A caspase-activated DNase that degrades DNA during apoptosis, and its inhibitor ICAD. Nature. 1998;391(6662):43-50.

[18] Tsujimoto Y, Cossman J, Jaffe E, Croce CM. Involvement of the bcl-2 gene in human follicular lymphoma. Science. 1985;228(4706):1440-3.

[19] Reed JC. Bcl-2 family proteins: regulators of apoptosis and chemoresistance in hematologic malignancies. Semin Hematol. 1997;34(4 Suppl 5):9-19.

[20] Minn AJ, Kettlun CS, Liang H, Kelekar A, Vander Heiden MG, Chang BS, Fesik SW, Fill M, Thompson CB. Bcl-xL regulates apoptosis by heterodimerization-dependent and -independent mechanisms. EMBO J. 1999;18(3):632-43.

[21] Narita M, Shimizu S, Ito T, Chittenden T, Lutz RJ, Matsuda H, Tsujimoto Y. Bax interacts with the permeability transition pore to induce permeability transition and cytochrome c release in isolated mitochondria. Proc Natl Acad Sci U S A. 1998;95(25):14681-6.

[22] Finucane DM, Bossy-Wetzel E, Waterhouse NJ, Cotter TG, Green DR. Bax-induced caspase activation and apoptosis via cytochrome c release from mitochondria is inhibitable by Bcl-xL. J Biol Chem. 1999;274(4):2225-33.

[23] Wang HG, Reed JC. Bc1-2, Raf-1 and mitochondrial regulation of apoptosis. Biofactors. 1998;8(1-2):13-6.

[24] Kuo TH, Kim HR, Zhu L, Yu Y, Lin HM, Tsang W. Modulation of endoplasmic reticulum calcium pump by Bcl-2. Oncogene. 1998;17(15):1903-10.

[25] Inohara N, Gourley TS, Carrio R, Mu?iz M, Merino J, Garcia I, Koseki T, Hu Y, Chen S, N??ez G. Diva, a Bcl-2 homologue that binds directly to Apaf-1 and induces BH3-independent cell death. J Biol Chem. 1998;273(49):32479-86.

[26] Wiman KG. p53: emergency brake and target for cancer therapy. Exp Cell Res. 1997;237(1):14-8.

[27] Mitry RR, Sarraf CE, Wu CG, Pignatelli M, Habib NA. Wild-type p53 induces apoptosis in Hep3B through up-regulation of bax expression. Lab Invest. 1997;77(4):369-78.

[28] Jost CA, Marin MC, Kaelin WG Jr. p73 is a simian [correction of human] p53-related protein that can induce apoptosis. Nature. 1997;389(6647):191-4.

[29] Osada M, Ohba M, Kawahara C, Ishioka C, Kanamaru R, Katoh I, Ikawa Y, Nimura Y, Nakagawara A, Obinata M, Ikawa S. Cloning and functional analysis of human p51, which structurally and functionally resembles p53. Nat Med. 1998;4(7):839-43.

[30] Elsing A, Burgert HG. The adenovirus E3/10.4K-14.5K proteins down-modulate the apoptosis receptor Fas/Apo-1 by inducing its internalization. Proc Natl Acad Sci U S A. 1998;95(17):10072-7.

[31] Suzuki A, Araki T, Miura M, Tsutomi Y. Functional absence of FADD in PLC/PRF/5 hepatoma cells: possible involvement in the transformation to hepatoma in HBV-infected hepatocytes. Proc Soc Exp Biol Med. 1999;221(1):72-9.

[32] Thome M, Schneider P, Hofmann K, Fickenscher H, Meinl E, Neipel F, Mattmann C, Burns K, Bodmer JL, Schr?ter M, Scaffidi C, Krammer PH, Peter ME, Tschopp J. Viral FLICE-inhibitory proteins (FLIPs) prevent apoptosis induced by death receptors. Nature. 1997;386(6624):517-21.

[33] Djerbi M, Screpanti V, Catrina AI, Bogen B, Biberfeld P, Grandien A. The inhibitor of death receptor signaling, FLICE-inhibitory protein defines a new class of tumor progression factors. J Exp Med. 1999;190(7):1025-32.

[34] Gottlieb SL, Myskowski PL. Molluscum contagiosum. Int J Dermatol. 1994;33(7):453-61.

[35] Bertin J, Armstrong RC, Ottilie S, Martin DA, Wang Y, Banks S, Wang GH, Senkevich TG, Alnemri ES, Moss B, Lenardo MJ, Tomaselli KJ, Cohen JI. Death effector domain-containing herpesvirus and poxvirus proteins inhibit both Fas- and TNFR1-induced apoptosis. Proc Natl Acad Sci U S A. 1997;94(4):1172-6.

[36] Perez D, White E. E1B 19K inhibits Fas-mediated apoptosis through FADD-dependent sequestration of FLICE. J Cell Biol. 1998;141(5):1255-66.

[37] Boulakia CA, Chen G, Ng FW, Teodoro JG, Branton PE, Nicholson DW, Poirier GG, Shore GC. Bcl-2 and adenovirus E1B 19 kDA protein prevent E1A-induced processing of CPP32 and cleavage of poly(ADP-ribose) polymerase. Oncogene. 1996;12(3):529-35.

[38] Hershberger PA, Dickson JA, Friesen PD. Site-specific mutagenesis of the 35-kilodalton protein gene encoded by Autographa californica nuclear polyhedrosis virus: cell line-specific effects on virus replication. J Virol. 1992;66(9):5525-33.

[39] Bertin J, Mendrysa SM, LaCount DJ, Gaur S, Krebs JF, Armstrong RC, Tomaselli KJ, Friesen PD. Apoptotic suppression by baculovirus P35 involves cleavage by and inhibition of a virus-induced CED-3/ICE-like protease. J Virol. 1996;70(9):6251-9.

[40] Bump NJ, Hackett M, Hugunin M, Seshagiri S, Brady K, Chen P, Ferenz C, Franklin S, Ghayur T, Li P, et al. Inhibition of ICE family proteases by baculovirus antiapoptotic protein p35. Science. 1995;269(5232):1885-8.

[41] Resnicoff M, Valentinis B, Herbert D, Abraham D, Friesen PD, Alnemri ES, Baserga R. The baculovirus anti-apoptotic p35 protein promotes transformation of mouse embryo fibroblasts. J Biol Chem. 1998;273(17):10376-80.

[42] Manji GA, Hozak RR, LaCount DJ, Friesen PD. Baculovirus inhibitor of apoptosis functions at or upstream of the apoptotic suppressor P35 to prevent programmed cell death. J Virol. 1997;71(6):4509-16.

[43] Chen P, Tian J, Kovesdi I, Bruder JT. Interaction of the adenovirus 14.7-kDa protein with FLICE inhibits Fas ligand-induced apoptosis. J Biol Chem. 1998;273(10):5815-20.

[44] Ekert PG, Silke J, Vaux DL. Inhibition of apoptosis and clonogenic survival of cells expressing crmA variants: optimal caspase substrates are not necessarily optimal inhibitors. EMBO J. 1999;18(2):330-8.

[45] Chiou SK, Tseng CC, Rao L, White E. Functional complementation of the adenovirus E1B 19-kilodalton protein with Bcl-2 in the inhibition of apoptosis in infected cells. J Virol. 1994;68(10):6553-66.

[46] See RH, Shi Y. Adenovirus E1B 19,000-molecular-weight protein activates c-Jun N-terminal kinase and c-Jun-mediated transcription. Mol Cell Biol. 1998;18(7):4012-22.

[47] Br?ker BM, Fickenscher H. Herpesvirus saimiri strategies for T cell stimulation and transformation. Med Microbiol Immunol. 1999;187(3):127-36.

[48] Nava VE, Cheng EH, Veliuona M, Zou S, Clem RJ, Mayer ML, Hardwick JM. Herpesvirus saimiri encodes a functional homolog of the human bcl-2 oncogene. J Virol. 1997;71(5):4118-22.

[49] Sarid R, Sato T, Bohenzky RA, Russo JJ, Chang Y. Kaposi's sarcoma-associated herpesvirus encodes a functional bcl-2 homologue. Nat Med. 1997;3(3):293-8.

[50] Cheng EH, Nicholas J, Bellows DS, Hayward GS, Guo HG, Reitz MS, Hardwick JM. A Bcl-2 homolog encoded by Kaposi sarcoma-associated virus, human herpesvirus 8, inhibits apoptosis but does not heterodimerize with Bax or Bak. Proc Natl Acad Sci U S A. 1997;94(2):690-4.

[51] Afanas'eva TA, Gurtsevich VE. [Molecular biological aspects of carcinogenesis associated with the Epstein-Barr virus]. Mol Biol (Mosk). 1998;32(6):940-7.

[52] Butenko AK. Smirnova IA. Kishinskaya EG. Detection of EBV genome in the lymph-node and peripheral-blood cells from patients of Chernobyl region with malignant-lymphomas. Eksp Onkol. 1994;16(2-3):164-8.

[53] Miller G. Biology of Epstein-Barr virus. Viral Oncology. Ed. G. Klein. New York: Raven press, 1980: 713-738.

[54] Yao QY, Ogan P, Rowe M, Wood M, Rickinson AB. Epstein-Barr virus-infected B cells persist in the circulation of acyclovir-treated virus carriers. Int J Cancer. 1989;43(1):67-71.

[55] Kenney JL, Guinness ME, Curiel T, Lacy J. Antisense to the epstein-barr virus (EBV)-encoded latent membrane protein 1 (LMP-1) suppresses LMP-1 and bcl-2 expression and promotes apoptosis in EBV-immortalized B cells. Blood. 1998;92(5):1721-7.

[56] Kawanishi M. Epstein-Barr virus BHRF1 protein protects intestine 407 epithelial cells from apoptosis induced by tumor necrosis factor alpha and anti-Fas antibody. J Virol. 1997;71(4):3319-22.

[57] Komano J, Sugiura M, Takada K. Epstein-Barr virus contributes to the malignant phenotype and to apoptosis resistance in Burkitt's lymphoma cell line Akata. J Virol. 1998;72(11):9150-6.

[58] Haviv I, Matza Y, Shaul Y. pX, the HBV-encoded coactivator, suppresses the phenotypes of TBP and TAFII250 mutants. Genes Dev. 1998;12(8):1217-26.

[59] Wang XW, Gibson MK, Vermeulen W, Yeh H, Forrester K, St?rzbecher HW, Hoeijmakers JH, Harris CC. Abrogation of p53-induced apoptosis by the hepatitis B virus X gene. Cancer Res. 1995;55(24):6012-6.

[60] Elmore LW, Hancock AR, Chang SF, Wang XW, Chang S, Callahan CP, Geller DA, Will H, Harris CC. Hepatitis B virus X protein and p53 tumor suppressor interactions in the modulation of apoptosis. Proc Natl Acad Sci U S A. 1997;94(26):14707-12.

[61] Maheswaran S, Englert C, Lee SB, Ezzel RM, Settleman J, Haber DA. E1B 55K sequesters WT1 along with p53 within a cytoplasmic body in adenovirus-transformed kidney cells. Oncogene. 1998;16(16):2041-50.

[62] Nevels M, Spruss T, Wolf H, Dobner T. The adenovirus E4orf6 protein contributes to malignant transformation by antagonizing E1A-induced accumulation of the tumor suppressor protein p53. Oncogene. 1999;18(1):9-17.

[63] Querido E, Marcellus RC, Lai A, Charbonneau R, Teodoro JG, Ketner G, Branton PE. Regulation of p53 levels by the E1B 55-kilodalton protein and E4orf6 in adenovirus-infected cells. J Virol. 1997;71(5):3788-98.

[64] Shen Y, Zhu H, Shenk T. Human cytomagalovirus IE1 and IE2 proteins are mutagenic and mediate "hit-and-run" oncogenic transformation in cooperation with the adenovirus E1A proteins. Proc Natl Acad Sci U S A. 1997;94(7):3341-5.

[65] Zhu H, Shen Y, Shenk T. Human cytomegalovirus IE1 and IE2 proteins block apoptosis. J Virol. 1995;69(12):7960-70.

[66] Bresnahan WA, Albrecht T, Thompson EA. The cyclin E promoter is activated by human cytomegalovirus 86-kDa immediate early protein. J Biol Chem. 1998;273(34):22075-82.

[67] Speir E, Modali R, Huang ES, Leon MB, Shawl F, Finkel T, Epstein SE. Potential role of human cytomegalovirus and p53 interaction in coronary restenosis. Science. 1994;265(5170):391-4.

[68] Yanai N, Obinata M. Apoptosis is induced at nonpermissive temperature by a transient increase in p53 in cell lines immortalized with temperature-sensitive SV40 large T-antigen gene. Exp Cell Res. 1994;211(2):296-300.

[69] McCarthy SA, Symonds HS, Van Dyke T. Regulation of apoptosis in transgenic mice by simian virus 40 T antigen-mediated inactivation of p53. Proc Natl Acad Sci U S A. 1994;91(9):3979-83.

[70] Jung YK, Yuan J. Suppression of interleukin-1beta converting enzyme (ICE)-induced apoptosis by SV40 large T antigen. Oncogene. 1997;14(10):1207-14.

[71] Conzen SD, Snay CA, Cole CN. Identification of a novel antiapoptotic functional domain in simian virus 40 large T antigen. J Virol. 1997;71(6):4536-43.

[72] Kim SH, Banga S, Jha KK, Ozer HL. SV40-mediated transformation and immortalization of human cells. Dev Biol Stand. 1998;94:297-302.

[73] Cook JL, Routes BA, Sompayrac L. Experimental tumour induction by SV40 transformed cells. Dev Biol Stand. 1998;94:303-9.

[74] Swan DC, Vernon SD, Icenogle JP. Cellular proteins involved in papillomavirus-induced transformation. Arch Virol. 1994;138(1-2):105-15.

[75] Lee JE, Kim CY, Giaccia AJ, Giffard RG. The E6 and E7 genes of human papilloma virus-type 16 protect primary astrocyte cultures from injury. Brain Res. 1998;795(1-2):10-6.

[76] Eick D, Hermeking H. Viruses as pacemakers in the evolution of defence mechanisms against cancer. Trends Genet. 1996;12(1):4-6.

[77] Edwards KM, Davis JE, Browne KA, Sutton VR, Trapani JA. Anti-viral strategies of cytotoxic T lymphocytes are manifested through a variety of granule-bound pathways of apoptosis induction. Immunol Cell Biol. 1999;77(1):76-89.

[78] Atkinson EA, Barry M, Darmon AJ, Shostak I, Turner PC, Moyer RW, Bleackley RC. Cytotoxic T lymphocyte-assisted suicide. Caspase 3 activation is primarily the result of the direct action of granzyme B. J Biol Chem. 1998;273(33):21261-6.

[79] Komiyama T, Quan LT, Salvesen GS. Inhibition of cysteine and serine proteinases by the cowpox virus serpin CRMA. Adv Exp Med Biol. 1996;389:173-6.

[80] Shresta S, Pham CT, Thomas DA, Graubert TA, Ley TJ. How do cytotoxic lymphocytes kill their targets? Curr Opin Immunol. 1998;10(5):581-7.

[81] Barry M, McFadden G. Virus encoded cytokines and cytokine receptors. Parasitology. 1997;115 Suppl:S89-100.

[82] Vozianov AF, Butenko AK, Zak KP. Cytokines: biological and antitumor properties. K.: Naukova Dumka, 1998. 317 p.

[83] Smyth MJ, Trapani JA. The relative role of lymphocyte granule exocytosis versus death receptor-mediated cytotoxicity in viral pathophysiology. J Virol. 1998;72(1):1-9.

[84] Malejczyk J, Malejczyk M, Breitburd F, Majewski S, Schwarz A, Expert-Besan?on N, Jablonska S, Orth G, Luger TA. Progressive growth of human papillomavirus type 16-transformed keratinocytes is associated with an increased release of soluble tumour necrosis factor (TNF) receptor. Br J Cancer. 1996;74(2):234-9.

[85] Feng P, Chan SH, Ooi EE, Soo MY, Loh KS, Wang D, Ren EC, Hu H. Elevated blood levels of soluble tumor necrosis factor receptors in nasopharyngeal carcinoma: correlation with humoral immune response to lytic replication of Epstein-Barr virus. Int J Oncol. 1999;15(1):167-72.

[86] Strockbine LD, Cohen JI, Farrah T, Lyman SD, Wagener F, DuBose RF, Armitage RJ, Spriggs MK. The Epstein-Barr virus BARF1 gene encodes a novel, soluble colony-stimulating factor-1 receptor. J Virol. 1998;72(5):4015-21.

[87] Lalani AS, Graham K, Mossman K, Rajarathnam K, Clark-Lewis I, Kelvin D, McFadden G. The purified myxoma virus gamma interferon receptor homolog M-T7 interacts with the heparin-binding domains of chemokines. J Virol. 1997;71(6):4356-63.

[88] Sieg S, Yildirim Z, Smith D, Kayagaki N, Yagita H, Huang Y, Kaplan D. Herpes simplex virus type 2 inhibition of Fas ligand expression. J Virol. 1996;70(12):8747-51.

[89] Schmitt CA, Lowe SW. Apoptosis and therapy. J Pathol. 1999;187(1):127-37.

[90] Phylchenkov AA. A role for apoptosis in tumorigenesis and its importance for cancer therapy: Recent insights. Eksperimentalnaya Onkologiya. 1998; 20(3-4): 259-70.

[91] Cinatl J Jr, Cinatl J, Vogel JU, Kotchetkov R, Driever PH, Kabickova H, Kornhuber B, Schwabe D, Doerr HW. Persistent human cytomegalovirus infection induces drug resistance and alteration of programmed cell death in human neuroblastoma cells. Cancer Res. 1998;58(2):367-72.

[92] Tanaka Y, Kameoka M, Ota K, Itaya A, Ikuta K, Yoshihara K. Establishment of persistent infection with HIV-1 abrogates the caspase-3-dependent apoptotic signaling pathway in U937 cells. Exp Cell Res. 1999;247(2):514-24.

[93] De Clercq E, Andrei G, Balzarini J, Hatse S, Liekens S, Naesens L, Neyts J, Snoeck R. Antitumor potential of acyclic nucleoside phosphonates. Nucleosides Nucleotides. 1999;18(4-5):759-71.

[94] Neyts J, Sadler R, De Clercq E, Raab-Traub N, Pagano JS. The antiviral agent cidofovir [(S)-1-(3-hydroxy-2-phosphonyl-methoxypropyl)cytosine] has pronounced activity against nasopharyngeal carcinoma grown in nude mice. Cancer Res. 1998;58(3):384-8.

[95] Hatse S, Schols D, De Clercq E, Balzarini J. 9-(2-Phosphonylmethoxyethyl)adenine induces tumor cell differentiation or cell death by blocking cell cycle progression through the S phase. Cell Growth Differ. 1999;10(6):435-46.

[96] Franek F, Holy A, Votruba I, Eckschlager T. Acyclic nucleotide analogues suppress growth and induce apoptosis in human leukemia cell lines. Int J Oncol. 1999;14(4):745-52.

[97] Li PX, Ngo D, Brade AM, Klamut HJ. Differential chemosensitivity of breast cancer cells to ganciclovir treatment following adenovirus-mediated herpes simplex virus thymidine kinase gene transfer. Cancer Gene Ther. 1999;6(2):179-90.

[98] Soler MN, Milhaud G, Lekmine F, Treilhou-Lahille F, Klatzmann D, Lausson S. Treatment of medullary thyroid carcinoma by combined expression of suicide and interleukin-2 genes. Cancer Immunol Immunother. 1999;48(2-3):91-9.

[99] Hall SJ, Mutchnik SE, Yang G, Timme TL, Nasu Y, Bangma CH, Woo SL, Shaker M, Thompson TC. Cooperative therapeutic effects of androgen ablation and adenovirus-mediated herpes simplex virus thymidine kinase gene and ganciclovir therapy in experimental prostate cancer. Cancer Gene Ther. 1999;6(1):54-63.

[100] Bouali-Benazzouz R, Lain? M, Vicat JM, Boisseau S, R?my C, Fouilh? N, Thomas F, Nissou MF, Benabid AL, Berger F. Therapeutic efficacy of the thymidine kinase/ganciclovir system on large experimental gliomas: a nuclear magnetic resonance imaging study. Gene Ther. 1999;6(6):1030-7.

[101] Engelmann C, Panis Y, Bolard J, Diquet B, Fabre M, Nagy H, Soubrane O, Houssin D, Klatzmann D. Liposomal encapsulation of ganciclovir enhances the efficacy of herpes simplex virus type 1 thymidine kinase suicide gene therapy against hepatic tumors in rats. Hum Gene Ther. 1999;10(9):1545-51.

[102] Craperi D, Vicat JM, Nissou MF, Mathieu J, Baudier J, Benabid AL, Verna JM. Increased bax expression is associated with cell death induced by ganciclovir in a herpes thymidine kinase gene-expressing glioma cell line. Hum Gene Ther. 1999;10(4):679-88.

[103] Herman JR, Adler HL, Aguilar-Cordova E, Rojas-Martinez A, Woo S, Timme TL, Wheeler TM, Thompson TC, Scardino PT. In situ gene therapy for adenocarcinoma of the prostate: a phase I clinical trial. Hum Gene Ther. 1999;10(7):1239-49.

[104] Raez L, Cabral L, Cai JP, Landy H, Sfakianakis G, Byrne GE Jr, Hurley J, Scerpella E, Jayaweera D, Harrington WJ Jr. Treatment of AIDS-related primary central nervous system lymphoma with zidovudine, ganciclovir, and interleukin 2. AIDS Res Hum Retroviruses. 1999;15(8):713-9.

[105] Shand N, Weber F, Mariani L, Bernstein M, Gianella-Borradori A, Long Z, Sorensen AG, Barbier N. A phase 1-2 clinical trial of gene therapy for recurrent glioblastoma multiforme by tumor transduction with the herpes simplex thymidine kinase gene followed by ganciclovir. GLI328 European-Canadian Study Group. Hum Gene Ther. 1999;10(14):2325-35.