Enhanced glutamine uptake influences composition of immune cell infiltrates in breast cancer

Background: Cancer cells must alter their metabolism to support proliferation. Immune evasion also plays a role in supporting tumour progression. This study aimed to find whether enhanced glutamine uptake in breast cancer (BC) can derive the existence of specific immune cells subtypes, including the subsequent impact on patient outcome.Method: SLC1A5, SLC7A5, SLC3A2 and immune cell markers; CD3, CD8, FOXP3, CD20 and CD68, in addition to PD1 and PDL1 were assessed using immunohistochemistry on TMAs constructed from a large BC cohort (n=803). Patients were stratified based on SLC protein expression into accredited clusters and correlated with immune cell infiltrates and patient outcome. The effect of transient siRNA knockdown of SLC7A5 and SLC1A5 on PDL1 expression was evaluated in MDA-MB-231 cells.Results: High SLCs were significantly associated with PDL1 and PD1+, FOXP3+, CD68+ and CD20+ cells (