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 tr ansition (G to A) at codon 497, resulting in a substitution of a lysin e for an arginine, was recently demonstrated in several human pancreat ic cancer cell lines. In the present study, we compared the frequency of expression of wild-type (HER497R) and variant (HER497K) EGF recepto rs in normal and malignant pancreatic tissue samples using single-stra nd conformation polymorphism analysis. Both receptors were expressed i n normal (42%) and malignant (46%) tissues. Three samples (two normal and one cancer) expressed only HER497K. The cancer sample that was hom ozygous for HER497K exhibited strong EGF receptor immunoreactivity. Th e high frequency of HER497K expression suggests that it is due to a re latively 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.