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The screening of cDNA expression libraries has proven to be a powerful method for identifying new tumor antigens. A limited number of tumor antigens for squamous cell carcinoma of the head and neck (SCCHN) have been identified. Immunoscreening of 2 million recombinant clones of a human SCCHN cDNA expression library derived from tumors of 4 patients led to isolation of 30 immunoreactive clones. These clones represented 8 distinct genes: mitochondrial transcription factor A, palladin, eukaryotic translation elongation factor 1 alpha 1, HDCMA18p, centromere autoantigen C, serologically defined colon cancer antigen 3, HSC70-interacting protein, and protein kinase C-binding protein. All of the identified genes are ubiquitously expressed in normal tissues. We used quantitative real time-PCR (QRT-PCR) to study the expression levels of selected genes in tumors and matched normal tissue samples from SCCHN patients. QRT-PCR showed elevated (defined by a greater than 2-fold difference) tumor expression of palladin in 8 of 14 (57%) paired tissue samples. Palladin is required for the normal organization of the actin cytoskeleton and focal adhesions. In addition, higher tumor expression was observed for mitochondrial transcription factor A (42 %), HDCMA18p (50%), and protein-kinase C-binding protein (55%) as compared to the matched normal tissue. These results suggest that altered transcriptional regulation of these genes may contribute to the development and progression of SCCHN. Further studies are required to elucidate specific functions of these proteins in malignancy.

[Proc Amer Assoc Cancer Res, Volume 45, 2004]