BMC Cancer 2009, 9:11 http://www.biomedcentral.com/1471-2407/9/11 Table 4: Univariate analysis of clinicopathologic parameters and gene expression Parameter GLUT3 HSAL2 PACE4 DOI Tumor size pStage Advanced T stage Recurrence N+ p < 0.0001 p = 0.015 p = 0.024 p = 0.009 p = 0.038 NS NS p-value p = 0.047 NS NS NS NS NS NS NS NS NS NS DOI = depth of invasion; pStage = pathologic stage; NS = not significant; N+ = presence of lymph node metastasis classified based on lymph node status and the presence of extracapsular spread. Among the genes that were shown to be associated with metastasis included MMP-9 [38]. Our findings show overexpression of numerous genes that have been previously shown in other DNA microar- ray studies to have a potential role in the development of head and neck carcinogenesis; these include MMP-1 and KRT16. Furthermore, we have identified and validated GLUT3 and HSAL2 to be potential prognosticator of head and neck SCC. Although the present study, like the others, is based on a relatively small number of patients and the findings do not allow us to draw definitive conclusion regarding their biological importance, it is the first to use large scale transcriptional profiling for predicting survival outcome in oral tongue SCC. Conclusion The use of high-density oligonucleotide probe arrays to identify gene expression differences between oral tongue SCC and normal tissues provide powerful means to decode the molecular events involved in the genesis and progression of oral SCC. Although these initial findings will need to be validated in relationship to clinical param- eters and outcome in larger patient cohorts, the character- ization of genes identified to be significant predictors by oligonucleotide microarray analysis may provide novel targets for the prognostication and treatment of oral cavity cancer. Finally, a large multi-institutional study including specimens of uniform characteristics using independent techniques to verify gene expression at the RNA, DNA and protein levels will be vital in reaching our ultimate of goal of improving the care of head and neck cancer patients. Abbreviations SCC: squamous cell carcinoma; CGH: comparative genomic hybridization; RT: reverse transcription; PCR: polymerase chain reaction; RR: risk ratio; CI: confidence intervals; EST: expressed sequence tag. Competing interests The authors declare that they have no competing interests. Authors' contributions CLE and PO performed all RNA extraction, RNA prepara- tion and real-time RT-PCR experiments and correlation and outcome analysis. They also drafted the manuscript. ST, TW and YY collected clinical data on patients involved in the study. NS performed all statistical analysis of the microarray data. DLC and RG reviewed all the histologic specimens. 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