Yiyun Lin, MS (Advisor: Nicholas Navin, PhD)

Investigating The Rare Aneuploid Cells in Normal Breast and Therapeutic Resistance in Triple Negative Breast Cancer Using Single Cell Genomics

     Aneuploid epithelial cells are common in breast cancer, however their presence in normal breast tissues is not well understood.  To address this question, we applied single cell DNA sequencing to profile copy number alterations (CNAs) in 83,206 epithelial cells from breast tissues of 49 healthy women and single cell DNA&ATAC co-assays to 19 women.  Our data shows that all women harbored rare aneuploid epithelial cells (median 3.19%) that increased with age. Many aneuploid epithelial cells (median 82.22%) in normal breast tissues underwent clonal expansions and harbored CNAs reminiscent of invasive breast cancers (gains of 1q, losses of 10q, 16q and 22q). Co-assay profiling showed that the aneuploid cells were associated with the two luminal epithelial lineages, while spatial mapping showed that they localized in ductal and lobular structures with normal histopathology. Collectively, these data show that even healthy women have clonal expansions of rare aneuploid epithelial cells in their breast tissues.

Advisory Committee:

• Nicholas Navin, PhD, Chair
• Ken Chen, PhD
• Lei Huo, MD, PhD
• Khandan Keyomarsi, PhD
• Clinton Yam, MD, MS

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Meeting ID: 846 8929 6806

Password: 257415