Variations of EGF-R surface expression in squamous cell carcinomas of the head and neck region. 
It has been previously found that the epidermal growth factor receptor (EGF-R) is highly expressed in squamous cell carcinomas of the head and neck region (SCCHN) and that this expression correlates with malignant transformation and tumor development.  We examined 9 SCCHN cell lines and a control keratinocyte cell line for EGF-R expression, utilizing fluorescence-activated cell sorting (FACS) and Western blot analysis.  Immuno-cytochemistry was performed to evaluate the receptor's cellular distribution.  We found the EGF-R to be up-regulated in SCCHN.  Surprisingly we did not see a clear correlation between tumor staging, grading or Stat3 signaling and EGF-R level but we observed up to three distinct EGF-R specific bands in our Western blots, implicating the presence of different protein isoforms.  Our data suggest that not only the amount but also the receptor function, including the presence of mutations, need to be considered in SCCHN malignancies.