New approaches are needed for the early detection of
breast cancer. Proteomic profiling technologies, such as surface-enhanced
laser desorption ionization mass spectrometry (SELDI-MS), may be able to identify
tumor markers in biological fluids. The objective of this study was to determine whether there are differences in
protein expression patterns in nipple aspirate fluid (NAF) from the cancerous and noncancerous breasts of patients with
unilateral breast cancer and the breasts of healthy volunteers. Paired NAF samples were obtained from 23 women with stage I or II unilateral invasive
breast carcinoma and five healthy female volunteers. Aliquots of the samples were applied to SELDI
Protein-chip arrays (WCX2 and IMAC3-Cu++), and
protein expression was analyzed using time-of-flight MS. A total of 463 distinct peaks were detected and analyzed. In
breast cancer patients, no differences in
protein expression were identified between the breast with the intact primary
carcinoma and the contralateral noncancerous breast. Seventeen peaks were overexpressed in
cancer-bearing breasts compared to breasts of healthy volunteers (p < 0.0005). When spectra from the nontumor-bearing breasts of
breast cancer patients were compared with spectra from breasts of healthy volunteers, two peaks that were overexpressed in
breast cancer patients and one peak that was underexpressed in
breast cancer patients were detected (p < 0.0027). SELDI-MS was able to identify differences in the phenotypic proteomic profile of NAF samples obtained from patients with early-stage
breast cancer and healthy women. Proteomic screening techniques such as SELDI-MS analysis of NAF may be useful for
breast cancer screening and diagnosis.