Susan Christine Massey, PhD
About Me
I am an applied mathematician using a combination of data analysis methods and mechanistic differential equation modeling, primarily in biomedical research. My passion is translating across domains, formalizing concepts mathematically to uncover new understanding in scientific areas, as well as helping other scientists and mathematicians to understand each others’ domain terminology. In my current position at Mayo Clinic, I work with cancer biologists, clinical neuro-oncologists and neuro-surgeons, as well as other applied mathematicians, bioinformaticists, and bioengineers, in a collective effort to gain new insights for treating glioblastoma.
As a former patient caregiver, I am also interested in philosophy of medicine and support efforts toward improved quality of life and early incorporation of palliative care and social support for patients and their families.
I earned my Ph.D. in Applied Mathematics from the University of Washington in 2016. Further details about my education, training, awards, teaching and mentorship can be found in my CV.
My Research
Assessing the impact of drug delivery versus sensitivity in glioblastoma treatment response
Glioblastoma is the most common type of brain cancer (and also the most aggressive). As part of a multi-center effort, we are trying to determine how the incomplete breakdown of the blood-brain barrier affects drug distribution in tumors. There are many ways we are studying this question, but my particular role has been using noninvasive imaging data from preclinical models to quantitatively assess the contributions of drug distribution and resistance to heterogeneous treatment outcomes.
Environmentally-driven glioma growth via paracrine PDGF signaling
My dissertation, Multi-scale modeling of paracrine PDGF-driven glioma growth and invasion, focused on exploring the role of paracrine platelet-derived growth factor (PDGF) signaling in the microenvironment of experimental proneural glioblastoma. Through mathematical modeling, I demonstrated that significant tumor growth can be driven by changes in the local brain tissue environment that cause normal progenitor cells to behave like cancer without undergoing mutation. This result validated and confirmed the mechanism suggested by experimental data from a PDGF-driven preclinical glioma model, developed by Peter Canoll and his lab at Columbia University College of Medicine.
Sensitivity analysis via Latin hypercube sampling and partial rank correlation coefficients
As part of model development, it can be helpful to study the sensitivity of the model outputs to the parameters. This is particularly true for parameter values that naturally vary according to some distribution or for parameters values that are difficult to estimate experimentally. One approach for investingating this sensitivity is to use Latin hypercube sampling of the model parameters to run monte carlo simulations and then assessing the partial rank correlation of the parameters with simulation results. I have applied this method for a number of models and am developing resources to make this technique easier to learn and utilize. Available on my GitHub page!
Publications
A selection of peer-reviewed and recently submitted (under review) articles - a full publication listing can be found on my google scholar page.
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Lesion dynamics under varying paracrine PDGF signaling in brain tissue
Bull. Math. Biol. 81(6):1645-16642019 -
ENvironmental Dynamics Underlying Responsive Extreme Survivors (ENDURES) of Glioblastoma: a Multi-disciplinary Team-based, Multifactorial Analytical Approach
American J. of Clinical Oncology 42(8):655-661 https://doi.org/10.1097/COC.00000000000005642019 -
Sex differences in predicting fluid intelligence of adolescent brain from T1-weighted MRIs
MICCAI Proceedings 2019 arXiv 1908.023332019 -
Simulating PDGF-Driven Glioma Growth and Invasion in an Anatomically Accurate Brain Domain.
Bull. Math. Biol. 80(5):1292-13092018 -
Comparative dynamics of microglial and glioma cell motility at the infiltrative margin of brain tumors
J. R. Soc. Interface. 15(139):201705822018 -
Direct Inhibition of Myosin II Effectively Blocks Glioma Invasion In the Presence of Multiple Motogens
Mol. Biol. Cell 23:533-5422012 -
Progenitor cell recruitment drives aggressive glioma growth: mathematical and experimental modeling
J. R. Soc. Interface. 9:1757-17662012 -
A subpopulation of neural stem/progenitor cells in the aged subventricular zone has increased mitotic activity
Stem Cells 29(12):2005-20172011 -
Frequency of abnormal findings detected by comprehensive evaluation at one year after allogeneic hematopoietic cell transplantation
Biol. Blood Marrow Transplant. 15(4):416-4202009
Events
I enjoy sharing my work - you may find me at one of these upcoming events! Additionally, you may look back through previous events I’ve presented at to find slides and other related resources.
2019 SNO-SCIDOT Joint Conference on Therapeutic Delivery to the CNS and the Annual Meeting of the Society for Neuro-Oncology
Presenting a poster on results from analysis of magnetic resonance image-localized histology specimens grouped by patient sex.
Women in Computational Biology Janelia Conference
Poster presentation of our Treatment Exposure Sensitivity model of treated brain tumor growth incorportating the contributions of both drug distribution and resistance.
7th International Conference on Mathematical Modeling and Analysis of Populations in Biological Systems
Gave a talk on combining ML and mechanistic models and presented a poster on behalf of a labmate
Annual Meeting of the Society for Mathematical Biology
Presented results from the sentivity analysis of our model exploring resistance and blood-brain barrier penetrance of an investigational drug.
q-bio Summer School
Presented a research lecture and gave a tutorial on Latin Hypercube Sampling for sensitivity analysis.
Inagural Cancer Systems Biology Consortium West Coast Symposium
Presented our latest work on assessing drug resistance and distribution from noninvasive imaging data.
Annual Meeting of the Society for Neuro-Oncology
Presented a poster summarizing the most recent update on work the different effects of drug sensitivity and variability in drug in heterogeneous tumors on noninvasive imaging.
Joint Physical Sciences-Oncology Network and Cancer Systems Biology Consortium Annual Investigators Meeting
Poster presentation featuring work that I and an undergraduate research assistant were beginning for investigating ways to assess drug blood-brain barrier pentetrability from noninvasive imaging data.
Joint Annual Meeting of the Society for Mathematical Biology and the Japanese Society for Mathematical Biology
I organized a mini symposium on Data--Driven Mechanistic Cancer Models featuring speakers Trachette Jackson, Kit Curtius, Lee Curtin, Jill Gallaher, and myself. My talk (slides linked below) featured some work I and an undergraduate assistant were beginning for investigating ways to assess drug blood-brain barrier pentetrability from noninvasive imaging data.
Annual Meeting of the Society for Neuro-Oncology
Highlighted an analysis of radiographic changes during adjuvant temozolomide therapy for glioblastoma.
Contact Me
If you are interested in working with me/collaborating, please reach out: susan@drmathy.org
For website feedback (e.g., to report a linking error), please send a message to: me@drmathy.org