Receptors for epidermal growth factor and estradiol in canine mammary tumors

Both growth factors and steroid hormones are known to be associated with breast cancer. We have studied the epidermal growth factor receptor (EGFR) in canine mammary tumors and have shown the presence of a single class of 125I-EGF binding receptor sites in 9 out of 13 (70%) tumors, using Scatchard plot. The dissociation constant (KD) was 10(-9)M. An inverse correlation between EGFR and estrogen receptor (ER) was observed in 54% of the tumors. Our data suggest that EGFR might be used as a biochemical marker in canine mammary tumors.