Cathepsin D andepidermal growth factor inhumanbreast cyst fluid

Although thedataare notunivocal (Page etal., 1978; Du- pontetal., 1985), several studies suggest that women with grosscystic disease havea greater risk ofdeveloping breast cancer(Haagensen etal., 1981). Thesecystsare lined by apocrine orflattened epithelium, theformer being atgreater riskofneoplastic transformation (Haagensen etal., 1981; Dixonetal., 1985). Because ofthese observations, breast cyst fluid (BCF)whichiseasily obtainable fromcystsbyaspira- tion, hasbeenextensively investigated inorder toidentify specific biochemical features related tocystevolution (Brad- lowetal., 1981; Jaspar etal., 1980; Boccardo etal., 1988; Battaglia etal., 1989; Hamedetal., 1990; Laietal., 1990). Theconcentrations ofelectrolytes inBCFhasbeenshownto becorrelated withthepathohistology ofthebreast (Dixon et al., 1985). Moreover we (Battaglia etal., 1989) andothers (Jaspar etal., 1980; Boccardo etal., 1988; Hamedetal., 1990; Todaro etal., 1980) reported thatBCFcontain large amountsofEpidermal GrowthFactor (EGF), whichhasa mitogenic effect on normal andneoplastic breast cells invitro andseems tobeinvolved intheautocrine regulation of breast cancerinvivo(Todaro etal., 1980; Osborne etal., 1980; Taketani etal., 1983). Thefinding thathigher EGF concentrations are present inapocrine thanflattened cysts havesuggested thatthisgrowth factor may beinvolved in mammary carcinogenesis (Boccardo etal., 1988; Battaglia et al., 1989; Hamedetal., 1990; Laietal., 1990). Garcia etal. (1986) reported thatBCFalso contain varying concentrations ofa Mr 52,000 (52K)secreted protein induced byoestrogen inMCF-7cells (Westley etal., 1979). Thisprotein hasbeen identified aspro-Cath-D, aproteolytic enzyme which displays a mitogenic effect invitro (Vignon etal., 1986; Morisset et al., 1986; Briozzo etal., 1988). Since atpresent no dataconcerning theconcentration of CathD indifferent cysttypes areavailable, we havestudied itsdistribution inseveral BCF,andresults havebeencor- related withEGF levels andcytological findings.