EGF in breast cyst fluid: relationships with intracystic androgens, estradiol and progesterone

Plasma enterolactone and breast cancer risk in the Nurses' Health Study II

Lignans are plant-based phytoestrogens with both estrogenic and anti-estrogenic properties that may be important for breast carcinogenesis. Retrospective studies have observed decreased breast cancer risk associated with high circulating enterolactone concentrations, a biomarker of lignan intake, but results from prospective studies are conflicting. To prospectively examine this association, we measured plasma enterolactone levels in 802 breast cancer cases and 802 matched controls nested among predominantly premenopausal women in the Nurses' Health Study II cohort. We used conditional logistic regression and polytomous logistic regression models, adjusting for known breast cancer risk factors, to calculate relative risks (RR) and 95 % confidence intervals (CI). Compared to women with enterolactone concentrations ≤4 nmol/L, the multivariate-adjusted RRs for breast cancer were 1.18 (95 % CI 0.86-1.62), 0.91 (95 % CI 0.66-1.25), and 0.96 (95 % CI 0.70-1.33) for women with enterolactone levels in the second to the fourth quartiles, respectively; P trend = 0.60. Results were similar across tumors defined by estrogen and progesterone receptor status. Among premenopausal women with follicular estradiol levels below the median (<47 pg/mL), women in the highest category of enterolactone levels had a 51 % lower breast cancer risk compared to those in the lowest category (95 % CI 0.27-0.91); P trend = 0.02. No association was observed among women with high-follicular estradiol levels (≥47 pg/mL), (comparable RR = 1.39, 95 % CI 0.73-2.65; P interaction = 0.02). We did not observe an overall association between plasma enterolactone and breast cancer risk in a large nested case-control study of US women. However, a significant inverse association was observed among premenopausal women with low-follicular estradiol levels, suggesting that enterolactone may be important in a low-estrogen environment. This should be confirmed in future studies.

Complement C3f serum levels may predict breast cancer risk in women with gross cystic disease of the breast

Gross cystic disease (GCDB) is a breast benign condition predisposing to breast cancer. Cryopreserved sera from GCDB patients, some of whom later developed a cancer (cases), were studied to identify potential risk markers. A MALDI-TOF mass spectrometry analysis found several complement C3f fragments having a significant increased abundance in cases compared to controls. After multivariate analysis, the full-length form of C3f maintained a predictive value of breast cancer risk. Higher levels of C3f in the serum of women affected by a benign condition like GCDB thus appears to be correlated to the development of breast cancer even 20 years later.

BIOLOGICAL SIGNIFICANCE

Increased complement system activation has been found in the sera of women affected by GCDB who developed a breast cancer, even twenty or more years later. C3f may predict an increased breast cancer risk in the healthy population and in women affected by predisposing conditions.

Breast cyst fluid plasmin activity and its effect on TGF-beta2 activation

There are two types of breast cyst and women with apocrine breast cyst may have a higher risk of developing breast cancer than cyst lined by flattened epithelium. Transforming growth factor-beta's growth inhibitory effect on epithelial cells suggests a potential protective role in breast cancer. The aim of this study was to investigate the presence of plasmin in both breast cyst groups and the possible role of plasmin on transforming growth factor beta activation. Presence of high plasmin level may indicate its importance on activation process, but some other proteases may also involve in this activation mechanism.

Breast cyst fluids increase the proliferation of breast cell lines in correlation with their hormone and growth factor concentration

OBJECTIVE AND DESIGN

Gross cystic disease (GCD) of the breast is reported to occur in 7% of women in the developed world and, although not premalignant, is thought to be associated with an increased risk of breast cancer. Hormone and growth factor concentration levels were measured in breast cyst fluid (BCF) to correlate them with their mitogenic activity in tumour (MCF-7) or nontransformed (MCF-10A) cells.

RESULTS

Oestradiol (E2), oestrone (E1), E2-sulfate (E2-S), E1-sulfate (E1-S) and epidermal growth factor (EGF) concentrations were, as expected, significantly higher in type I than in type II cysts, while transforming growth factor-beta 2 (TGF-beta2) showed higher levels in type II cysts. Fifty per cent of the BCF samples stimulated [3H]-thymidine incorporation into MCF-7 cells while 34.5% inhibited this parameter. In MCF-10A cells, most BCF samples were stimulatory (85%). E2, E1 and EGF concentrations in BCF samples correlated significantly and positively with cell proliferation in MCF-7 cells, whereas a significant negative correlation was found for TGF-beta2. In MCF-10A cells, only E2-S and E1-S exhibited significant positive correlation, whereas a significant negative correlation was found for TGF-beta2. Progesterone (Pg), E2 and EGF incubated under the same conditions had a stimulatory effect on [3H]-thymidine incorporation into MCF-7 cells, whereas TGF-beta2 inhibited this parameter. Pg, E2, E1 and EGF significantly stimulated this parameter in MCF-10A cells.

CONCLUSIONS

The stimulatory action of BCF on cell proliferation in a model of human breast epithelial cells could partly explain the increased incidence of breast cancer in cyst-bearing women.

Human gross cyst breast disease and cystic fluid: bio-molecular, morphological, and clinical studies

For more than one and a half century the cystic disease of the breast has been recognized as the most frequent female benign breast lesion. Although some conundrums and controversies exist about the relation between gross cysts and breast cancer, recent evidence suggests that the multidisciplinary study of gross cystic breast disease (GCBD) may be a powerful tool for predicting the natural history of the multifaceted gross cyst pathology. A lot of papers have been published on breast cyst fluids (BCF) concerning biochemical, hormonal and morphological aspects, demonstrating that the intracystic fluid contains a wide variety of components (such as ions, lipids, proteins, enzymes, growth factors and antigens) and suggesting that their profile provides additional knowledge on both physiopathology and etiologic pathways of human gross cystic breast disease. The aim of this overview is the critical evaluation of all data accumulated in the last thirty years, in order to highlight the utility of biochemical and epidemiological studies to identify gross cysts, if any, at higher breast cancer risk.

Serum enterolactone levels and the risk of breast cancer in women with palpable cysts

Low levels of lignans, namely enterolactone, have been reported to be associated with an increased risk of breast cancer in the general female population. We assessed, retrospectively, the relationship between serum enterolactone concentrations and the occurrence of breast cancer in women with palpable cysts. The levels of enterolactone in cryopreserved serum aliquots, obtained from 383 women with palpable cysts at the time of their first cyst aspiration, were measured using a time-resolved fluoroimmunoassay (TR-FIA). After a median follow-up time of 6.5 years (range 0.5-12.75 years), 18 women were found to have developed an invasive breast cancer. Median values of serum enterolactone were significantly lower in women who subsequently developed breast cancer: 8.5 nM/l versus 16.0 nM/l: P=0.04. Odd Ratios (OR) for breast cancer were: 0.36 (P=0.03), 0.57 (P=0.3) and 0.38 (P=0.25) for 25th (8 nM/l), 50th (16 nM/l) and 75th (24 nM/l) percentile values, respectively. The receiver operating characteristic (ROC) analysis showed a satisfactory accuracy for enterolactone as a breast cancer risk indicator (area under the curve (AUC)=0.64: P=0.04). Logistic regression analysis confirmed that the enterolactone concentration had a strong protective effect on the breast cancer risk. These findings may have important clinical implications with regard to interventional diet-focused chemo-preventive trials.

Enterolactone in breast cyst fluid: correlation with EGF and breast cancer risk

The purpose of our study was to investigate whether enterolactone does accumulate into breast cyst fluid and whether it correlates with breast cancer risk. We included 258 women who had at least one cyst aspiration and known intracystic cation and epidermal growth factor (EGF) concentration values. For 191 of such women serum aliquots were also available. The median value of serum enterolactone was 17 nM/l (range 1-140 nM/l). The median intracystic level of enterolactone was much higher (63 nM/l, range 0-872 nM/l) and was significantly higher in type I cysts (p = 0.000). This cyst type contained also significantly higher levels of EGF (p = 0.000). A direct relationship was found between serum and cyst fluid enterolactone levels (p = 0.000) and between cyst enterolactone and EGF levels (p = 0.03), the latter correlation being evident especially in type II cysts. Twelve patients in the cohort of women were found to have developed a breast cancer. After univariate analysis breast cancer risk was associated with cyst type and especially with EGF concentration. No association was evident for enterolactone concentration. However, enterolactone concentration appeared to significantly decrease the risk of patients with high EGF concentrations. Our results show that enterolactone does accumulate in breast cysts, and that it modulates the risk related to the intracystic level of EGF, which is confirmed to be a strong predictor of breast cancer risk.

The expression of EGFR family ligands in breast carcinomas

Expression of EGF, HB-EGF, TGF-alpha, HRG-alpha, HRG-beta1, and HRG-beta3 in 100 frozen breast carcinoma materials was immunohistochemically studied. Among these tumors, 67% were positive for EGF, 53% for HB-EGF, 57% for TGF-alpha, 60% for HRG-alpha, 53% for HRG-beta1, and 63% for HRG-beta3 in the neoplastic epithelial cells. No significant associations between expression of the growth factors and clinicopathological features like tumor size, histologic grade, node status, ploidy, ER status, and c-erbB-4 expression were observed, with the exceptions that significant relations were present between EGF expression and tumor size (p = 0.01) and between HRG-beta3 expression and node status (p = 0.02). The expressions of these growth factors showed no association with cancer-specific survival by the Kaplan Meier analysis.

Intracystic epidermal growth factor level is predictive of breast-cancer risk in women with gross cystic disease of the breast

Women affected by gross cystic disease of the breast have an increased risk of breast cancer. We report here the incidence of breast cancer by cyst type and intracystic epidermal growth factor (EGF) concentration. Our retrospective study included 504 women who had at least 1 cyst aspiration between 1985 and 1993. Cyst fluids were processed for electrolyte concentration (n = 378), EGF concentration (n = 347) or both (n = 337). Age-standardized incidence ratios (SIRs) were estimated using the population of the Genoa Cancer Registry. A multivariate Poisson regression model was used to estimate relative risks (RRs) when the study groups were compared directly. By June 1999, 19 invasive breast cancers had developed in the cohort of women. The age SIR of breast cancer calculated for the whole cohort was 3.32 (95% confidence interval 2.00-5.18). The ratio was not affected by age and was only moderately increased in women with a positive family history of breast cancer and type I cysts (i.e., those with a Na+/K+ ratio <3). However, it was significantly increased in women with high EGF concentrations. Direct comparisons confirmed that age, cyst type and family history only moderately increased the RR, whereas EGF concentration was a strong predictor of risk. Our results confirm that women affected by palpable cysts have an increased risk of developing breast cancer and suggest that the risk is higher in women with high intracystic EGF concentrations.

Insulin-like growth factor binding protein-3 in breast cyst fluid: relationships with insulin-like growth factors I and II and transforming growth factor-beta 1 and 2

Women who have palpable breast cysts with intracystic Na/K > 3 may have a lower risk of developing breast cancer than those with intracystic Na/K < 3. In this study significantly higher concentrations of insulin-like growth factor-binding protein-3 (IGFBP-3), insulin-like growth factors I and II (IGF-I, IGF-II) and transforming growth factor-beta 2 (TGF-beta2) were found in the Na/K > 3 sub-group. No difference was found in transforming-growth factor-beta 1 (TGF-beta1) levels between the two sub-groups of breast cysts. A positive correlation was obtained for IGFBP-3 and TGF-beta1 in the Na/ K > 3 sub-group consistent with reports that TGF-beta1 may regulate the production of IGFBP-3. Equimolar amounts of total IGFs and IGFBP-3 in breast cyst fluid imply that most, if not all, of these IGFs are protein-bound. The significantly higher concentrations of TGF-beta2 in the Na/K > 3 sub-group may partly explain the lower risk of breast cancer in this group of women.

Prostate-specific antigen in breast cyst fluid: possible role of prostate-specific antigen in hormone-dependent breast cancer

Prostate-specific antigen (PSA) is a 33 kDa serine protease which is produced by many different tissues in the body and has been shown to be present in low concentrations in breast milk and in about 30% of breast cancers. The presence of PSA in breast cancers is associated with the presence of steroid-hormone receptors and may be a favourable prognostic indicator. In this study, PSA immunoreactivity was measured in breast cyst fluid obtained from women with palpable breast cysts which is the most common benign breast disease. PSA was found to be present in very low concentrations in breast cyst fluid. In an attempt to understand the possible role of PSA in the breast, the effect of PSA on growth of the hormone-dependent MCF-7 and hormone-independent MDA-MB-231 human breast cancer cell lines was studied. In addition, the effect of PSA on oestrone sulphatase activity and oestrogen 17-oxidoreductase activity in these cell lines was investigated. PSA, in low concentrations, was found to inhibit MCF-7 cell growth and to stimulate the conversion of oestradiol to the less potent oestrogen oestrone in this cell line. PSA had no effect on the MDA-MB-231 cell line. Our findings suggest that PSA may act as a negative growth regulator in hormone-dependent breast cancers.

Epidermal growth factor content of breast cyst fluids from women with breast cancer or proliferative disease of the breast

The intracystic electrolyte content is generally used to identify different breast cyst subpopulations: cysts containing high K+ levels have been associated with an increased risk of subsequent breast cancer. In order to define whether other biochemical features of breast cyst fluid (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). Median intracystic EGF levels were significantly higher in patients with breast cancer or atypical hyperplasia than in cysts of women without any 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 not different either from controls or from the other study groups. No significant difference among groups was observed in the prevalence of Na+/K+ < 3 cysts, this being the most frequently observed type of cysts in all groups except in that with proliferative disease without atypia. No significant difference in EGF levels between cysts ipsilateral or contralateral to the biopsy was observed within each histological group. Our results indicate that EGF levels are higher in cysts aspirated from breasts with an associated proliferative pathology, either benign or neoplastic. The determination of intracystic EGF, combined with that of electrolyte content, might help to identify a subset of patients with gross cystic disease of the breast at potentially higher risk of developing breast cancer.

Presence of immunoassayable transforming growth factor-beta 1 (TGF-beta 1) in breast cyst fluid (BCF): relationship with the intracystic electrolyte and epidermal-growth-factor (EGF) content

We evaluated the presence and distribution of transforming growth factor-beta 1 (TGF-beta 1) in breast cyst fluid (BCF), and its relationship with intracystic epidermal growth factor (EGF). EGF and TGF-beta 1 were determined by radioimmunoassay on 47 BCFs (27 of the Na+/K+ < 3 type and 20 of the Na+/K+ > 3 type). As expected, EGF levels were inversely correlated with the Na+/K+ ratio, and were consequently higher in Na+/K+ < 3 cysts as compared with Na+/K+ > 3 cysts, (p < 0.005). By contrast, TGF-beta 1 levels were directly correlated with the Na+/K+ ratio (p < 0.01), being higher in Na+/K+ > 3 cysts, though not significantly (p = 0.057). A significant negative relationship was found between EGF and TGF-beta 1 concentration. When the analysis was performed separately in the 2 cyst sub-populations, EGF and TGF-beta 1 were found to be negatively and significantly correlated in Na+/K+ < 3 cysts only (p < 0.01). Our results demonstrate that Na+/K+ < 3 cysts contain high levels of EGF, a growth-stimulating factor, and very low levels of TGF-beta 1, a growth-inhibiting factor. This may provide an explanation for the higher risk of breast cancer observed in women with Na+/K+ < 3 cysts. Our results also suggest that EGF accumulation in this type of cysts might be regulated by TGF-beta 1.

Oncostatin M, interleukin 2, interleukin 6 and interleukin 8 in breast cyst fluid

Women with breast cysts lined by apocrine epithelium (intracystic Na/K < 3) may have a higher risk of developing breast cancer than those whose breast cysts are lined by "flattened" epithelium (intracystic Na/K < 3). In this study, the concentrations of the cytokines, oncostatin M (OSM), interleukin 2 (IL-2), interleukin 6 (IL-6) and interleukin 8 (IL-8) were measured in breast cyst fluid, OSM, IL-2 and IL-6 having been shown to have growth-inhibitory actions on tumour cells. All cytokines were measured by "sandwich" enzyme immunoassays. IL-2 was not detectable in breast cyst fluid. OSM, IL-6 and IL-8 concentrations were significantly higher in the high-electrolyte-ratio group. Although significant positive correlations were found between OSM and IL-6, OSM and IL-8, OSM and Na/K, IL-6 and IL-8, IL-6 and Na/K and IL-8 and Na/K when all samples were analysed together, analysis of the correlations between these analytes in each subgroup separately suggests that the control of production of these cytokines or the mechanism of entry into cyst fluid is likely to be different for the 2 cyst types. The significantly higher intracystic concentrations of OSM and IL-6 in the high-electrolyte-ratio group may partly explain the lower risk of breast cancer in this group of women.

Tumor markers in patients with advanced breast cancer as prognosticators: a preliminary study

A retrospective study was performed on 69 breast cancer patients (stage II, N = 18; advanced disease, N = 51) in order to assess the prognostic value of circulating prolactin (PRL), CEA, CA 15-3, insulin-like growth factor-1 (IGF-1), and epidermal growth factor (EGF) by RIA/IRMA. These markers were compared with short-term prognosis (two years). Significant difference was observed only for PRL ( < 20.0 ng/ml vs. > 20.0 ng/ml), which provide an independent predictor of short-term prognosis in advanced breast cancer.

Possible regulation of soluble ICAM-1 levels by interleukin-1 in a sub-set of breast cysts

There are 2 main groups of breast cysts characterized by their intracystic sodium-to-potassium ratios. Women who have intracystic Na/K < 3 may have a higher risk of developing breast cancer than those who have intracystic Na/K > 3. The cell adhesion molecule, ICAM-I, has been shown to be inducible by interleukin-I (IL-I). Furthermore, ICAM-I may be involved in the progression of metastasis in certain malignancies. The aim of this study was to measure intracystic soluble ICAM-I (sICAM-I) and IL-I alpha/beta levels and to assess the relationships between these substances. Wide-ranging concentrations of sICAM-I, IL-I alpha and IL-I beta were found in breast-cyst fluid. The high-electrolyte-ratio group had intracystic levels of sICAM-I and IL-I beta which were significantly higher than those of the low-electrolyte-ratio group. No significant difference was found between IL-I alpha concentrations in the 2 groups of breast cysts. Strong positive correlations were found between sICAM-I and IL-I alpha, sICAM-I and IL-I beta, and IL-I alpha and IL-I beta. The significance of the higher concentrations of sICAM-I in the high-electrolyte-ratio group remains to be determined, but the results of this study suggest that sICAM-I levels in the high-electrolyte-ratio group may be regulated in part by IL-I alpha and IL-I beta.

Relationships between oestrogen-inducible proteins, oestradiol and electrolyte ratio in breast cyst fluid

Women who have breast cysts with intracystic Na+/K+ < 3 may have a higher risk of developing breast cancer than women who have breast cysts with intracystic Na+/K+ > 3. In this study wide-ranging intracystic concentrations of cathepsin D and pS2 (oestrogen inducible proteins/polypeptides) as well as oestradiol were found. The concentrations of cathepsin D and oestradiol were significantly higher in the low electrolyte ratio cyst group than in the high electrolyte ratio cyst group. No significant difference was found between pS2 concentrations in the two groups. The significantly higher intracystic concentrations of cathepsin D, a mitogenic lysosomal endopeptidase and oestradiol in the low electrolyte ratio group may partly provide an explanation for the higher risk of breast cancer which has been observed in this group of women.