Proteomics analysis of human breast milk to assess breast cancer risk

Abstract

Detection of breast cancer (BC) in young women is challenging because mammography, the most common tool for detecting BC, is not effective on the dense breast tissue characteristic of young women. In addition to the limited means for detecting their BC, young women face a transient increased risk of pregnancy-associated BC. As a consequence, reproductively active women could benefit significantly from a tool that provides them with accurate risk assessment and early detection of BC. One potential method for detection of BC is biochemical monitoring of proteins and other molecules in bodily fluids such as serum, nipple aspirate, ductal lavage, tear, urine, saliva and breast milk. Of all these fluids, only breast milk provides access to a large volume of breast tissue, in the form of exfoliated epithelial cells, and to the local breast environment, in the form of molecules in the milk. Thus, analysis of breast milk is a non-invasive method with significant potential for assessing BC risk. Here we analyzed human breast milk by mass spectrometry (MS)-based proteomics to build a biomarker signature for early detection of BC. Ten milk samples from eight women provided five paired-groups (cancer versus control) for analysis of dysregulatedproteins: two within woman comparisons (milk from a diseased breast versus a healthy breast of the same woman) and three across women comparisons (milk from a woman with cancer versus a woman without cancer). Despite a wide range in the time between milk donation and cancer diagnosis (cancer diagnosis occurred from 1 month before to 24 months after milk donation), the levels of some proteins differed significantly between cancer and control in several of the five comparison groups. These pilot data are supportive of the idea that molecular analysis of breast milk will identify proteins informative for early detection and accurate assessment of BC risk, and warrant further research. Data are available via ProteomeXchange with identifier PXD007066.

Comparative two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE) of human milk to identify dysregulated proteins in breast cancer

“…The enzymes that are used for the metabolism of lipids as well as their corresponding pathways are dysregulated in different kinds of diseases, including cancer (reviewed in reference ). In a recent study done by our group on 5 paired BC versus control samples, including the same pair that is used for this study, on human breast milk, we found human bile salt also downregulated in 2 (including the same pair that is used in this study) out of 5 BC samples versus controls .…”

“…In our recent previous study several proteins from the casein family were downregulated in four of the five BC versus control comparisons, including kappa-casein isoform X2 [30]. It should be mentioned that among 11 dysregulated caseins identified in the present study, only one casein was found to be upregulated in spot number 347, the other ten caseins were downregulated.…”

“…Downregulation (fold change of 3 to 20) of epidermal and adipose fatty acid binding proteins also has been observed in prostate cancer in a study done on both prostate cancer cell lines and prostate cancer tumor tissues using RT-PCR [69]. Regarding the alterations in fatty acids and their related proteins in BC, it must be mentioned that in our previous study done on five paired BC versus control samples, including the same pair used for this study, on human breast milk, we found fatty acid synthase also downregulated in all five out of five BC samples versus controls [30].…”

“…Investigation of potential BC biomarkers is an emerging technology for risk assessment and early diagnosis of BC. Recently, different studies have been performed to investigate potential biomarkers of caner [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], including the investigations on breast milk [25][26][27][28][29][30]. As reviewed previously, a non-invasive tool for early detection of BC could be particularly beneficial for women of reproductive age, as current imaging tools are less effective in detecting cancer in the relatively dense breasts of younger women, and because the incidence of pregnancy associated BC is predicted to increase as the age of first pregnancy increase.…”

“…As reviewed previously, a non-invasive tool for early detection of BC could be particularly beneficial for women of reproductive age, as current imaging tools are less effective in detecting cancer in the relatively dense breasts of younger women, and because the incidence of pregnancy associated BC is predicted to increase as the age of first pregnancy increase. Empirical studies support the use of human milk to investigate potential BC biomarkers [27][28][29][30][31][32][33][34][35]. Dysregulated proteins in breast milk could provide potential biomarkers of BC.…”