Educational Session 7: Immune Microenvironment

V. F. Borges; University of Colorado Anschutz Medical Campus, Aurora, CO.

Young onset breast cancer has been identified as having a high risk for the development of metastatic disease and death. Historically, the poorer prognosis among those diagnosed under age 45 had been attributed to higher stage at diagnosis due to the absence of screening in those under 40 or older and also to a higher frequency of the breast cancers being hormone receptor negative and HER2 negative or HER2 positive. As treatments have advanced, outcomes improved, and our ability to interrogate the tumor microenvironment expanded, we still see a persistent difference in the risk for developing distant metastasis and death from breast cancer in young-onset disease. The immune profile of people with young onset breast cancer and the infiltration of immune cells in their tumors has lead to important clues for why these disparate outcomes exist. This lecture will review the current understanding of the interaction between the immune system and young onset breast cancer, the different subtypes of the disease and the differences seen in outcomes.