Date of Graduation

5-2022

Document Type

Thesis

Degree Name

Bachelor of Science

Degree Level

Undergraduate

Department

Biomedical Engineering

Advisor/Mentor

Rajaram, Narasimhan

Committee Member/Reader

Quinn, Kyle

Abstract

Breast cancer, accounting for 12% of all new cancer cases, is one of the leading causes of death in women worldwide. Although patient survival has improved over the years, metastatic spread to other organ sites and not due to the primary tumor is the most common form of tumor recurrence, accounting for 90% deaths. Hypoxia is a common hallmark of solid tumors and is linked with metastasis, therapeutic resistance, and poor patient survival. Defined as a state of decreased oxygen availability, cells under hypoxia have an increased rate of genetic mutation, local invasion, and resistance to treatment such as radiation and chemotherapy. Previous studies have explored the connection between breast cancer receptor status to the eventual metastatic nature of a tumor; however, the functional characteristics of these tumors remain in question. In this study, diffuse reflectance spectroscopy (DRS) was used to evaluate functional changes in tumor xenografts originated from two breast cancer cell lines with variable metastatic potential. The murine mammary cell lines 4T1 and 67NR were injected into the right flanks of mice to grow tumor xenografts. Optical data from these tumor bearing animals was collected and using an empirical model, vascular oxygen saturation (SO2) and total hemoglobin concentration (cHb) was determined. Results indicated constant hemoglobin content in both cell lines across all time points of measurements and upward of vascular oxygen saturation in both metastatic and nonmetastatic tumors. Overall, this pilot study could aid in the understanding of the role that hypoxia has on breast tumors at a fundamental level and open the door for future studies in answering questions pertaining to specific pathways/tumor microenvironment that occur in response to such conditions both in vitro and in vivo.

Keywords

Diffuse reflectance spectroscopy; Hypoxia; Tumor microenvironment; Breast cancer; Metastasis

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