For the past decade, Dr. Jeffrey's lab has performed molecular profiling of cancer cells with the goal of identifying tumor-specific therapies for the personalized treatment of cancer.

Dr. Jeffrey was a member of the collaborative Stanford/Norway team that pioneered the use of DNA microarrays to measure global gene expression in solid tumors, and was involved in the development of the currently accepted classification schema for breast cancer subtypes based on gene expression profiles- such as low and high proliferation luminal, ERBB2(HER2)-overexpressing, and basal-like breast cancers (which then focused attention on triple negative breast cancers). Her laboratory refined RNA amplification techniques and developed expertise in the transcriptional profiling of tiny quantities of tumor tissue and in RNA isolation from formalin-fixed paraffin-embedded samples.

Dr. Jeffrey's research currently involves extracting and profiling circulating tumor cells (CTCs) from blood and bone marrow to shed light on the metastatic process and eventually to help guide selection of appropriate therapies in individual cancer patients.