<qa>  What is the pattern of global gene expression in a HNSCC specimen?Previous research by our group using genetic microarray analysis of HNSCC and normal keratinocytes has identified two distinct groups of genetic expression based on clustering patterns of a subgroup of genes. Clinical data was summarized for each group and overall, patient segregation by gene expression profiling was a better predictor of outcome than clinicopathological variables. Further analysis identified 375 genes that discriminate between the genotypic subtypes of HNSCC. Overall, our preliminary data has shown that the pattern of global gene expression in a HNSCC specimen can be used as a predictor of prognosis. We isolated subsets of genes showing the greatest patterns of divergence in gene expression. We have also identified 366 over-expressed and 246 underexpressed genes when comparing primary tumor to normal surgical margins and have identified a similar number of genes whose expression has changed when comparing primary tumor to lymph node metastasis. Combining these data sets we have identified genes which consistently increase or decrease expression during progression from normal tissue to primary tumor, and subsequently to metastatic node. We have selected several candidate genes for subsequent analysis using HNSCC tissue arrays. Through DNA microarray analysis and other techniques for looking at genetic and molecular characteristics, a more detailed knowledge of the malignant transformation process, and alterations with therapy, in these patients may be obtained. This study will seek to perform comprehensive molecular and genetic profiling to improve biomarker development in HNSCC and correlate this data with patient clinical data. Ultimately it is hoped that tumor specific genetic abnormalities may be identified which could provide targets for treatment strategies such as gene therapy, immunotherapy, or other interventions. 