Introduction: Breast cancer often takes many years and multiple genetic or epigenetic mutations for detectable tumor development to occur. The mutation or loss of expression of key tumor suppressor genes, such as p53 and BRCA1, is associated with a higher risk and earlier development of breast cancer. My hypothesis is that proper functioning of these tumor suppressor genes will protect against epigenetic changes associated with the early initiation of cancer. To test this hypothesis we will compare syngeneic immortalized breast epithelial cells with and without engineered mutations in BRCA1 or p53. We will expose the cells in the presence or absence of cytokines to mimic chronic inflammation and examine the levels of DNA methyltransferases and TET methylcytosine dioxygenases.

Materials and Methods: Cell lines used will be MCF10A breast cells with an engineered BRCA185delAG mutation and/or Crispr/cas9 knockout of 53, as well as four immortalized human mammary epithelial cell lines (2 BRCA mutant and 2 BRCA WT) with and without p53 knockouts. Quantitative RT-PCR and Western blot analysis will be  performed to assess levels of the methylation machinery. Immunohistochemistry will be performed to look at DNMT1, DNMT3a and DNMT3b expression in normal breast tissue from the Rays of Hope Center for Breast Research Registry.

Results: Thus far, it appears the p53 knockout (p53KO) is associated with elevated DNMT expression in two of the four HMEC lines, in addition to the MCF10A cells. 

Conclusion: These results suggest the loss of p53 activity may facilitate breast epithelial transformation through altered epigenetic changes.