Thirty-five percent of patients (82) had tumours with greater than 10 fmol mg-1 I125-EGF binding (EGFr+) and 47% (109) and cystolic ER concentrations greater than 5 fmol mg-1 (ER+), with a marked inverse relationship between EGFr and ER (P less than 0.00001). Here, EGF is linked to neoplasm.