EPIDERMAL GROWTH-FACTOR CONTENT OF BREAST CYST FLUIDS FROM WOMEN WITHBREAST-CANCER OR PROLIFERATIVE DISEASE OF THE BREAST

The intracystic electrolyte content is generally used to identify diff erent breast cyst subpopulations: cysts containing high K+ levels have been associated with an increased risk of subsequent breast cancer. I n order to define whether other biochemical features of breast cyst fl uid (BCF) might further explain such an increased risk, we determined the content of epidermal growth factor (EGF), a known mitogenic factor for normal and transformed breast epithelium, in cysts of women with breast cancer or proliferative lesions of the breast (atypical ductal or lobular hyperplasia and proliferative disease without atypia). Medi an intracystic EGF levels were significantly higher in patients with b reast cancer or atypical hyperplasia than in cysts of women without an y clinical or instrumental evidence of proliferative disease chosen as controls (p < 0.05 and p < 0.01, respectively). In patients affected by proliferative disease without atypia, intracystic EGF levels were n ot different either from controls or from the other study groups. No s ignificant difference among groups was observed in the prevalence of N a+/K+ < 3 cysts, this being the most frequently observed type of cysts in all groups except in that with proliferative disease without atypi a. No significant difference in EGF levels between cysts ipsilateral o r contralateral to the biopsy was observed within each histological gr oup. Our results indicate that EGF levels are higher in cysts aspirate d from breasts with an associated proliferative pathology either benig n or neoplastic. The determination of intracystic EGF, combined with t hat of electrolyte content, might help to identify a subset of patient s with gross cystic disease of the breast at potentially higher risk o f developing breast cancer.