Glycoprotein Profiles of Human Breast Cells Demonstrate a Clear Clustering of Normal/Benign versus Malignant Cell Lines and Basal versus Luminal Cell Lines

Gene expression profiling has defined molecular subtypes of breast cancer including those identified as luminal and basal. To determine if glycoproteins distinguish various subtypes of breast cancer, we obtained glycoprotein profiles from 14 breast cell lines. Unsupervised hierarchical cluster analysis demonstrated that the glycoprotein profiles obtained can serve as molecular signatures to classify subtypes of breast cancer, as well as to distinguish normal and benign breast cells from breast cancer cells. Statistical analyses were used to identify glycoproteins that are overexpressed in normal versus cancer breast cells, and those that are overexpressed in luminal versus basal breast cancer. Among the glycoproteins distinguishing normal breast cells from cancer cells are several proteins known to be involved in cell adhesion, including proteins previously identified as being altered in breast cancer. Basal breast cancer cell lines overexpressed a number of CD antigens, including several integrin subunits, relative to luminal breast cancer cell lines, whereas luminal breast cancer cells overexpressed carbonic anhydrase 12, clusterin, and cell adhesion molecule 1. The differential expression of glycoproteins in these breast cancer cell lines readily allows the classification of the lines into normal, benign, malignant, basal, and luminal groups.