Salivary Protein Profiles among HER2/neu-Receptor-Positive and -Negative Breast Cancer Patients: Support for Using Salivary Protein Profiles for Modeling Breast Cancer Progression

Abstract

Purpose. The objective of this study was to compare the salivary protein profiles from individuals diagnosed with breast cancer that were either HER2/neu receptor positive or negative. Methods. Two pooled saliva specimens underwent proteomic analysis. One pooled specimen was from women diagnosed with stage IIa HER2/neu-receptor-positive breast cancer patients (n = 10) and the other was from women diagnosed with stage IIa HER2/neu-receptor-negative cancer patients (n = 10). The pooled samples were trypsinized and the peptides labeled with iTRAQ reagent. Specimens were analyzed using an LC-MS/MS mass spectrometer. Results. The results yielded approximately 71 differentially expressed proteins in the saliva specimens. There were 34 upregulated proteins and 37 downregulated proteins.

Figure 1

This figure illustrates the protein profiles for HER2/neu-receptor-positive and HER2/neu-receptor-negative samples. As shown in the far right red and green dyed gel comparisons, there are numerous differences between the two profiles.

Figure 2

This figure demonstrates the differences in salivary protein profiles between HER2/neu -positive and HER2/neu -negative samples. Please change.

Figure 3

The figure represents the natural logarithm differential expression of salivary proteins. To the right and left of the figure listed in rank order of expression are the up- and downregulated proteins, respectively.

Figure 4

This figure represents the percentage of expressed proteins according to their cellular function.

Figure 5

It illustrates the presence of profilin-1 in the SKBR3 and HSG cell lysates and saliva sampled from healthy, benign, and malignant tumor patients. Profilin is a downregulated protein in the presence of malignancy, and it is visualized by the lighter bands associated with malignancy. It is also worth noting that the Her2/neu-receptor-negative band is darker than the Her2/neu-receptor-positive counterpart suggesting further downregulation of the profiling-1 protein.