Trained first as a molecular biologist and fascinated by oncogenes, Dr. Weidhaas was drawn to oncology, and trained as a radiation oncologist at MSKCC. During her time there as a Holman Pathway Fellow, she did postdoctoral work in genetics. At MSKCC she developed the first genetic model of the radiation response in a living organism, C. elegans.
After moving to Yale as a physician scientist, she began her fascination with microRNAs, the first non-coding RNAs discovered. Her goal was to uncover the cause of their dysregulation, to define how they could be used to help her cancer patients.
She focused her work on becoming an expert on microRNA detection, and understanding how microRNAs were involved in cancer therapy. Her group was the first to show that microRNAs are critical in the radiation response. She then turned her efforts onto understanding how the important
microRNA, let-7, interacted with the oncogene KRAS. She, together with Frank Slack, PhD, discovered the first example of a cancer associated inherited microRNA disrupting mutation, now referred to as the KRAS-variant. This inherited difference, found in 6% of the worlds population, explains up to 25% of newly diagnosed cancer in women, and broadly predicts unique responses to cancer therapy.