otide Polymorphism (SNP) array and GDAS software.Both RNA and DNA were extracted from each tumor.

Method of Data Analysis: Software packages: GCOS,GDAS, RMA, SAM.

Results: Our work demonstrates clear patterns of chro-mosomal imbalances and gene expression profiles asso-ciated with both UK and Sri Lankan oral cancer and thatthese are grossly different. Within each cohort sub-groups can be defined on the basis of gene expressionpatterns and close correlations are drawn with clinicalfeatures of the tumors. We shall also demonstrate howchromosomal imbalances appear to have an effect ongene expression patterns and that these are unique toeach cohort.

Conclusion: This work clearly demonstrates uniquepatterns of chromosomal imbalance and gene expres-sion associated with oral cancer arising from two distinctaetiological groups. Furthermore these patterns can becorrelated to the clinical course of the disease.

References

Alizadeh AA, et al: Nature 403:503, 2000Nagata M, et al: Int J Cancer 106:683, 2003O’Donnell R, et al: Oncogene online 2004 doi:10.1038/sj.onc.208285

Gene Expression Changes in Response toTherapeutic Doses of Irradiation andMolecular Manipulation to Change SuchResponses in an Oral Cancer Cell LineVictor Lopes, FRCS, FDSRCS, Department ofMaxillofacial Surgery, University Hospital BirminghamNHS Trust, Edgbaston, Birmingham, West MidlandsB15 2TH, UK (Offer N; Wei WB; Murray P)

Statement of the Problem: Investigating the effects ofionising radiation on cells cultured in-vitro has alwaysbeen difficult because of concerns regarding dosimetry.Frequently investigators have been forced to use gammasources and have assumed 100% dose absorption. Wehave developed a protocol that simulates a biologicalsystem and is carefully dose controlled. This system willallow adherent oral cancer cell lines to be irradiated in amanner similar to a tumor within the body. As a result itis possible to study genome wide gene expressionchanges in oral cancer cell lines; about which to datelittle is understood.

Materials and Methods: We examined the gene expres-sion changes in the oral cancer cell line SCC4 at 3, 6, and12 hours post-irradiation with gamma rays. Therapeuticdoses of irradiation (2-4 Gy) were used in a single frac-tion. RNA was extracted from the cells in culture andeach irradiation was repeated 3 times. We used theAffymetrix focus array to determine gene expression ateach time point. Gene expression changes were vali-dated by RT-PCR and Western blotting.

Method of Data Analysis: Software packages GCOS,RMA, and SAM.

Results: Using therapeutic doses of radiation (2-4 Gy)we can show that the great majority of gene expressionchanges occur within the first 3 hours after irradiationand that by 12 hours there are few changes in geneexpression compared to unirradiated cells. We also dem-onstrate that a large proportion of the conventional DNAdamage response genes are not activated after a singlefraction of radiation to the p53 mutant cell line SCC4.However we are able to demonstrate a dramatic upregu-lation of one of the cohesin sub-units which is respon-sible for homologous recombination (DNA repair). Wehave also shown that this same gene is not upregulatedin p53 wild type cell lines in response to irradiation butis upregulated in a proportion of ex-vivo irradiated pri-mary oral cancers. We shall also present data showingthat manipulation of the expression of this gene canhave effects on the cell dramatically changing the re-sponse of the cell to irradiation.

Conclusion: Modifying the cellular response to irradi-ation may in future prove to be a useful therapeuticintervention. In particular, amplifying cellular responsemay allow radiation dose reduction. This would be mostadvantageous when radiation is used as an adjuvant ther-apy. Here the benefits are less clear when compared topotential complications. Dose reduction would reducecomplications and improve the safety profile of adjuvantradiotherapy.

References

Birkenbihl RP, et al: Nucleic Acids Res 20:6605, 1992Zhang Y, et al: Radiat Res 161:667, 2004

Characterization of Neuropilin-1 inSquamous Cell Carcinoma of the Tongue:A Laboratory StudySanjay Sharma, BDS, MBBS, FDSRCS, MRCSI, MRCS, 5Cadgwith Place, Port Solent, Hampshire PO6 4TD, UK(Quintera-Ortiz M; Spedding A; Anand R; Faris K;Brennan P; Cree I)

Statement of the Problem: Angiogenesis is a key pro-cess in the growth of all solid tumors. Neuropilin-1 hasrecently been identified as a co-receptor for vascularendothelial growth factor receptor 2 (VEGFR2) and en-hances the binding of VEGF-165 to VEGFR2 promotingendothelial cell proliferation. Neuropilin-1 has been de-scribed in breast, prostate, and lung cancers. We aim tocharacterize neuropilin-1 in squamous cell carcinoma.

Materials and Methods: Immunohistochemical stain-ing of 38 paraffin fixed sections of primary tongue squa-mous cell carcinoma (SCC) with antibodies to NRP-1,VEGF-165, and CD34. Real-time quantitative polymerasechain reaction (RT-qPCR) and Western blots of SCC celllines for mRNA and protein respectively.

Oral Abstract Session 2

40 AAOMS • 2005