Salivary protein profile modeling for studying breast cancer progression

Objectives: A model that can reflect the presence and progression of malignancy among women would enhance our knowledge of breast cancer. The idea is the use of salivary protein profiling as a novel model for determining breast cancer activity and its response to therapy. We hypothesize that, secondary to breast cancer, the malignancy’s rapid growth alters the proteomic content of the tissue microenvironment and that these changes may manifest in up or down regulation of salivary protein concentrations, which can be used as a sentinel body fluid for breast cancer modeling.

Methods: We tested the model by comparing Zinc alpha2 glycoprotein concentrations across four types of breast tissue cells lines which were grown in culture and monitored continuously until each cell line reached confluence allowing for a protein analysis to be performed. The breast tissue cell lines are as follows: 184B5-Normal; AU565-positive for Her2, Her3, Her4 and p53; HCC-negative for Her2 neu, Progesterone Receptor and Estrogen Receptor positive for p53; SKBR3-Her 2 neu/ over expressed. Zn2GC expression was compared between the four different cell lines in two types of Elisa plates. The total protein in each cell lysate was analyzed in accordance with the amount of Zn2GC captured on the MA Elisa plate

Results: ELISA assays indicated that Zn2GP concentrations are up regulated in malignant breast cancer cell lines as compared to a healthy control. Additionally, Zn2GP concentrations are up regulated in the saliva of breast cancer patients in comparison to healthy and benign tumor subjects. Salivary Zn2GP concentrations were modulated in response to treatment and in the presence of tumor recurrence.

Conclusions: The results suggest that salivary gland secretions may have utility in modeling breast cancer progression.  Additionally, salivary Zn2GC may have potential for monitoring patient response to treatment and for the presence of tumor recurrence.