Single-strand conformation polymorphism analysis of the epidermal growth factor receptor at codon 497

A variant human epidermal growth factor (EGF) receptor (HER) with a transition (G to A) at codon 497, resulting in a substitution of a lysine for an arginine, was recently demonstrated in several human pancreatic cancer cell lines. In the present study, we compared the frequency of expression of wild-type (HER497R) and variant (HER497K) EGF receptors in normal and malignant pancreatic tissue samples using single-strand conformation polymorphism analysis. Both receptors were expressed in normal (42%) and malignant (46%) tissues. Three samples (two normal and one cancer) expressed only HER497K. The cancer sample that was homozygous for HER497K exhibited strong EGF receptor immunoreactivity. The high frequency of HER497K expression suggests that it is due to a relatively common polymorphism in the HER coding region. Its presence in some of the cancer samples suggests that, like the wild-type receptor, HER497K also has a role in pancreatic cancer.