Differential expression of cancer-associated proteins in breastmilk.

Breast cancer that develops during or shortly after pregnancy is frequently more aggressive than cancer diagnosed at other times in a woman's life. To better understand the patterns of cancer-related protein expression in the breasts of lactating women, we determined the differences in total and individual protein expression in milk based on (a) three time points during lactation (early, mid, and late), (b) length of lactation, and (c) parity. Breastmilk was collected from 72 healthy lactating women within 10 days of starting lactation (transitional [T]), 2 months after lactation started, and during breast weaning (W). Sixteen proteins whose expression is altered in breast cancer (11 kallikreins [KLKs], basic fibroblast growth factor [bFGF], YKL-40, neutrophil gelatinase-associated lipocalin, and transforming growth factor [TGF] ß1 and ß2) were evaluated. The concentration of total milk protein decreased over time (p<0.01 at 2 months and W compared with T). After we controlled for total protein, KLK6 and TGFß2 significantly increased, and bFGF decreased from T to W. Neither length of nursing nor parity significantly influenced individual protein expression at the W time point. On the other hand, length of nursing did influence the difference in KLK6, -7, and -8 expression between the W and T time points. Total milk protein concentration is lower in the mid and late phases of nursing. Biomarker differences between T and W milk samples in KLK6, TGFß2, and bFGF are consistent with a protective effect of nursing.

Differential expression of cancer associated proteins in breast milk based on age at first full term pregnancy.

BACKGROUND: First full term pregnancy (FFTP) completed at a young age has been linked to low long term breast cancer risk, whereas late FFTP pregnancy age confers high long term risk, compared to nulliparity. Our hypothesis was that proteins linked to breast cancer would be differentially expressed in human milk collected at three time points during lactation based on age at FFTP. METHODS: We analyzed breast milk from 72 lactating women. Samples were collected within 10 days of the onset of lactation (baseline-BL), two months after lactation started and during breast weaning (W). We measured 16 proteins (11 kallikreins (KLKs), basic fibroblast growth factor, YKL-40, neutrophil gelatinase-associated lipocalin and transforming growth factor (TGF) ß-1 and -2) associated with breast cancer, most known to be secreted into milk. RESULTS: During lactation there was a significant change in the expression of 14 proteins in women < 26 years old and 9 proteins in women > = 26 at FFTP. The most significant (p < .001) changes from BL to W in women divided by FFTP age (< 26 vs. > = 26) were in KLK3,6, 8, and TGFß2 in women < 26; and KLK6, 8, and TGFß2 in women > = 26. There was a significant increase (p = .022) in KLK8 expression from BL to W depending on FFTP age. Examination of DNA methylation in the promoter region of KLK6 revealed high levels of methylation that did not explain the observed changes in protein levels. On the other hand, KLK6 and TGFß1 expression were significantly associated (r2 = .43, p = .0050). CONCLUSIONS: The expression profile of milk proteins linked to breast cancer is influenced by age at FFTP. These proteins may play a role in future cancer risk.

Proteins and carbohydrates in nipple aspirate fluid predict the presence of atypia and cancer in women requiring diagnostic breast biopsy.

BACKGROUND: Herein we present the results of two related investigations. The first study determined if concentrations in breast nipple discharge (ND) of two proteins (urinary plasminogen activator, uPA and its inhibitor, PAI-1) predicted the presence of breast atypia and cancer in pre- and/or postmenopausal women requiring surgery because of a suspicious breast lesion. The second study assessed if these proteins increased the predictive ability of a carbohydrate (Thomsen Friedenreich, TF) which we previously demonstrated predicted the presence of disease in postmenopausal women requiring surgery. METHODS: In the first study we prospectively enrolled 79 participants from whom we collected ND, measured uPA and PAI-1 and correlated expression with pathologic findings. In the second study we analyzed 35 (uPA and PAI-1 in 24, uPA in an additional 11) ND samples collected from different participants requiring breast surgery, all of whom also had TF results. RESULTS: uPA expression was higher in pre- and PAI-1 in postmenopausal women with 1) cancer (DCIS or invasive) vs. either no cancer (atypia or benign pathology, p = .018 and .025, respectively), or benign pathology (p = .017 and .033, respectively); and 2) abnormal (atypia or cancer) versus benign pathology (p = .018 and .052, respectively). High uPA and PAI-1 concentrations and age were independent predictors of disease in premenopausal women, with an area under the curve (AUC) of 83-87% when comparing diseased vs. benign pathology. uPA, TF, and age correctly classified 35 pre- and postmenopausal women as having disease or not 84-91% of the time, whereas combining uPA+PAI-1+TF correctly classified 24 women 97-100% of the time. CONCLUSIONS: uPA and PAI-1 concentrations in ND were higher in women with atypia and cancer compared to women with benign disease. Combining uPA, PAI-1 and TF in the assessment of women requiring diagnostic breast surgery maximized disease prediction. The assessment of these markers may prove useful in early breast cancer detection.

Trans-resveratrol alters mammary promoter hypermethylation in women at increased risk for breast cancer.

Trans-resveratrol, present in high concentration in the skin of red grapes and red wine, has a dose-dependent antiproliferative effect in vitro, prevents the formation of mammary tumors, and has been touted as a chemopreventive agent. Based upon in vitro studies demonstrating that trans-resveratrol downregulates the expression of 1) DNA methyltransferases and 2) the cancer promoting prostaglandin (PG)E(2), we determined if trans-resveratrol had a dose-related effect on DNA methylation and prostaglandin expression in humans. Thirty-nine adult women at increased breast cancer risk were randomized in double-blind fashion to placebo, 5 or 50 mg trans-resveratrol twice daily for 12 wk. Methylation assessment of 4 cancer-related genes (p16, RASSF-1α, APC, CCND2) was performed on mammary ductoscopy specimens. The predominant resveratrol species in serum was the glucuronide metabolite. Total trans-resveratrol and glucuronide metabolite serum levels increased after consuming both trans-resveratrol doses (P < .001 for both). RASSF-1α methylation decreased with increasing levels of serum trans-resveratrol (P = .047). The change in RASSF-1α methylation was directly related to the change in PGE(2) (P = .045). This work provides novel insights into the effects of trans-resveratrol on the breast of women at increased breast cancer risk, including a decrease in methylation of the tumor suppressor gene RASSF-1α. Because of the limited sample size, our findings should be validated in a larger study.

Breast cancer biomarkers predict weight loss after gastric bypass surgery.

BACKGROUND: Obesity has long been associated with postmenopausal breast cancer risk and more recently with premenopausal breast cancer risk. We previously observed that nipple aspirate fluid (n) levels of prostate specific antigen (PSA) were associated with obesity. Serum (s) levels of adiponectin are lower in women with higher body mass index (BMI) and with breast cancer. We conducted a prospective study of obese women who underwent gastric bypass surgery to determine: 1) change in n- and s-adiponectin and nPSA after surgery and 2) if biomarker change is related to change in BMI. Samples (30-s, 28-n) and BMI were obtained from women 0, 3, 6 and 12 months after surgery. FINDINGS: There was a significant increase after surgery in pre- but not postmenopausal women at all time points in s-adiponectin and at 3 and 6 months in n-adiponectin. Low n-PSA and high s-adiponectin values were highly correlated with decrease in BMI from baseline. CONCLUSIONS: Adiponectin increases locally in the breast and systemically in premenopausal women after gastric bypass. s-adiponectin in pre- and nPSA in postmenopausal women correlated with greater weight loss. This study provides preliminary evidence for biologic markers to predict weight loss after gastric bypass surgery.

Serum Müllerian inhibiting substance levels are lower in premenopausal women with breast precancer and cancer.

BACKGROUND: In preclinical studies, müllerian inhibiting substance (MIS) has a protective affect against breast cancer. Our objective was to determine whether serum MIS concentrations were associated with cancerous or precancerous lesions. Blood from 30 premenopausal women was collected and serum extracted prior to their undergoing breast biopsy to assess a suspicious lesion found on imaging or physical examination. Based on biopsy results, the serum specimens were grouped as cancer (invasive or ductal carcinoma in situ), precancer (atypical hyperplasia or lobular carcinoma in situ), or benign. FINDINGS: Serum from women with cancer and precancer (p = .0009) had lower MIS levels than serum from women with benign disease. CONCLUSION: Our findings provide preliminary evidence for MIS being associated with current breast cancer risk, which should be validated in a larger population.

Carbohydrate antigens in nipple aspirate fluid predict the presence of atypia and cancer in women requiring diagnostic breast biopsy.

BACKGROUND: The goal of this prospective study was to determine (a) concentrations of the carbohydrate biomarkers Thomsen Friedenreich (TF) antigen and its precursor, Tn antigen, in nipple discharge (ND) collected from women requiring biopsy because of a suspicious breast lesion; and (b) if concentration levels predicted pathologic diagnosis. METHODS: Adult women requiring biopsy to exclude breast cancer were enrolled and ND obtained. The samples from 124 women were analyzed using an anti-TF and anti-Tn monoclonal antibodies in direct immunoassay. RESULTS: The highest median concentration in ND for TF and Tn was in women with ductal carcinoma in situ (DCIS). TF was higher in women with 1) cancer (DCIS or invasive) vs. either no cancer (atypia or benign pathology, p = .048), or benign pathology (p = .018); and 2) abnormal (atypia or cancer) versus benign pathology (p = .016); and was more predictive of atypia or cancer in post- compared to premenopausal women. Tn was not predictive of disease. High TF concentration and age were independent predictors of disease, correctly classifying either cancer or abnormal vs. benign pathology 83% of the time in postmenopausal women. CONCLUSIONS: TF concentrations in ND were higher in women with precancer and cancer compared to women with benign disease, and TF was an independent predictor of breast atypia and cancer. TF may prove useful in early breast cancer detection.

Nipple aspirate fluid proteome of healthy females and patients with breast cancer.

BACKGROUND: The ductal/alveolar system of the female breast constantly secretes and reabsorbs fluid in nonpregnant/nonlactating women. This fluid, referred to as nipple aspirate fluid (NAF), can be obtained by a noninvasive procedure and it is part of the microenvironment where more than 95% of breast cancers arise. METHODS: Using an Orbitrap mass analyzer coupled to a linear ion trap, we performed an in-depth proteomic analysis of NAF samples obtained from 3 healthy individuals and 3 patients with breast cancer. Multiple fractionation methods such as size-exclusion and anion-exchange chromatography were applied for protein separation before mass spectrometric analysis. RESULTS: We identified more than 800 unique proteins in total, generating the most extensive NAF proteome thus far. Using gene ontology, we classified the identified proteins by their subcellular localization and found that more than 50% were extracellular or plasma membrane proteins. By searching against the Plasma Proteome Database, we confirmed that 40% of the proteins were also found in the plasma. Unigene database searching for transcripts of the proteins not found in the plasma revealed that the vast majority were expressed in the mammary gland. CONCLUSIONS: Our extensive proteome database for NAF may be helpful in the identification of novel cancer biomarkers.

uPA is upregulated by high dose celecoxib in women at increased risk of developing breast cancer.

BACKGROUND: While increased urokinase-type plasminogen activator (uPA) expression in breast cancer tissue is directly associated with poor prognosis, recent evidence suggests that uPA overexpression may suppress tumor growth and prolong survival. Celecoxib has been shown to have antiangiogenic and antiproliferative properties. We sought to determine if uPA, PA inhibitor (PAI)-1 and prostaglandin (PG)E2 expression in nipple aspirate fluid (NAF) and uPA and PGE2 expression in plasma were altered by celecoxib dose and concentration in women at increased breast cancer risk. METHODS: NAF and plasma samples were collected in women at increased breast cancer risk before and 2 weeks after taking celecoxib 200 or 400 mg twice daily (bid). uPA, PAI-1 and PGE2 were measured before and after intervention. RESULTS: Celecoxib concentrations trended higher in women taking 400 mg (median 1025.0 ng/mL) compared to 200 mg bid (median 227.3 ng/mL), and in post- (534.6 ng/mL) compared to premenopausal (227.3 ng/mL) women. In postmenopausal women treated with the higher (400 mg bid) celecoxib dose, uPA concentrations increased, while PAI-1 and PGE2 decreased. In women taking the higher dose, both PAI-1 (r = -.97, p = .0048) and PGE2 (r = -.69, p = .019) in NAF and uPA in plasma (r = .45, p = .023) were correlated with celecoxib concentrations. CONCLUSION: Celecoxib concentrations after treatment correlate inversely with the change in PAI-1 and PGE2 in the breast and directly with the change in uPA in the circulation. uPA upregulation, in concert with PAI-1 and PGE2 downregulation, may have a cancer preventive effect.

Biomarkers associated with breast cancer are associated with obesity.

BACKGROUND: Obesity is linked to the development of postmenopausal breast cancer, and some studies indicate obesity predicts a worse prognosis for premenopausal women who develop the disease. It was our hypothesis that proteins associated with breast cancer would be associated with body mass index (BMI). METHODS: We searched our database of women enrolled in breast health translational research trials for information on BMI and markers predictive of breast cancer (basic fibroblast growth factor (bFGF), prostate-specific antigen (PSA), human kallikrein (hK)2, and urinary plasminogen activator (uPA). Information on BMI and one or more nipple aspirate fluid (NAF) or serum biomarkers was available from 382 women. RESULTS: In this data set, NAF and serum levels of PSA (nPSA and sPSA), and NAF levels hK2, bFGF and uPA were each associated with pre- and/or postmenopausal breast cancer. sPSA was inversely associated with BMI in both pre- (r=-.56, p=.001) and postmenopausal women (r=-.62, p=.0035) without breast cancer. This association was lost when controlling for plasma volume. In women without breast cancer, NAF bFGF (p=.07, premenopausal subjects) and NAF hK2 (p=.09, postmenopausal subjects) were borderline associated with BMI. In women with breast cancer, nPSA was inversely (r=-.53, p=.049) associated with BMI in premenopausal women and directly associated with BMI in postmenopausal women (r=.37, p=.017). nPSA trended higher in hormone sensitive cancers, especially those that expressed progesterone receptor (p=.059). CONCLUSIONS: sPSA was inversely associated with BMI in all pre- and postmenopausal women and specifically in pre- and postmenopausal women without breast cancer. NAF PSA was associated with BMI in pre- and postmenopausal women with breast cancer. Evaluating the change in PSA with changes in weight may provide clues regarding a subject's breast cancer risk.

Prospective multicenter trial to determine the feasibility of collection and predictive ability of breast fluid analysis in postmenopausal women receiving SERMs.

We conducted a prospective ancillary study to the study of tamoxifen and raloxifene (STAR) trial involving 4 institutions to determine: (1) our ability to collect nipple aspirate fluid (NAF) in postmenopausal women taking medication to decrease breast proliferation and (2) NAF biomarkers associated with breast cancer. NAF was collected before and 6 months after starting treatment. Three biomarkers, cytology, fluid volume, and prostate-specific antigen (PSA), were analyzed. NAF was collected from 26 of 33 (79%) enrolled subjects at baseline. We were able to collect fluid in 84% of the subjects who produced NAF at baseline and returned for second aspiration after 6 months of treatment. In these women, cytology was unchanged in 85%, improved in 11%, and worsened in 4% of breasts. Median PSA increased from 37.5 to 112 ng/L after treatment. NAF volume did not significantly change. In conclusion, after treatment with tamoxifen or raloxifene, changes in both NAF cytology and PSA were generally favorable, consistent with their expected antiproliferative effective effect on the breast. Multiinstitutional clinical trials in postmenopausal women using NAF biomarkers as the primary endpoints are feasible.