Greiner is a board-certified physician assistant. She specializes in integrative oncology, which is the use of complementary medicines along with traditional therapies for cancer care.

Greiner assists patients with a cancer diagnosis through treatment, symptom management and beyond. She helps patients flourish by improving their quality of life and well-being and educating them with strategies to reduce the risk of recurrence.

Her interests include culinary medicine, which is teaching basic cooking skills needed for preparing high-quality meals for optimum health.

Greiner has been involved in research on body composition and cancer prognosis.

She received her master's degree in physician assistant studies at Wingate University and her PhD in nutrition at Cornell University.