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Jeffrey Xiong

Jeffrey Xiong

Jeffrey Xiong, a sophomore biology and creative writing double major at Columbia University, studied variation in gene expression in cancer cells for genes implicated in depression.

Past research has indicated that patients with major depressive disorder (MDD) are more likely to get certain kinds of cancer, such as brain cancer and breast cancer.

My experiences with BSRP and the Broad this summer has been incredibly transformative in how I approach science. From getting detailed advice on how to approach various stages in a scientific career, to in-depth practice with scientific communication and presenting, to learning about how to become a leader to others and myself within science, to talking closely with and getting mentorship from people at the Broad, to just having fun with everyone else in the program and learning from each other, I have grown immensely from these weeks. I am very excited to take these lessons and grow even further as a scientist and I am eager to see where everyone heads as well!There is also a surprising known overlap of certain genes between these two disorders. This project aims to use computational techniques on existing genomic data infrastructure -- the Cancer Cell Line Encyclopedia (CCLE) and a survey of patients with MDD from Taiwan -- to understand this difference. We developed a new metric relating cancer dependency (a measure of how reliant cancer cells are on a gene to survive) with fold-change values of genes implicated in MDD to draw statistical conclusions on genetic relatedness.

I discovered that there does not exist a statistically significant in gene dependency scores between cancers implicated in patients with MDD versus cancers that uniformly manifest. This implies that a cell-line-based approach to explain this phenomenon is insufficient. Furthermore, when analyzing major outliers within gene data, I found no statistically significant difference in expression between cancer types. Thus, we reject the initial assumption that there is a single-cell genetic factor to explaining why patients with MDD are more prone to certain cancers.

Nevertheless, we did find that gene expression between cancers does significantly vary. In addition, specific genes, such as FDXO48 and CSDC2, are major outliers compared to other genes in the CCLE database. Thus, we recommend that these genes be subject to further experimentation to explain how they function in both cancer and MDD. We also recognize that a multi-cellular or systemic analysis could yield the answer for the difference in cancer incidence rates for people with MDD.


Project: Cell-line-based expression approach for genes implicated in cancer and depression

Mentor: Megan Tse, Blainey Lab