Red blood cells protein profile is modified in breast cancer patients

Metastasis is the primary cause of death for most breast cancer patients who succumb to the disease. During the haematogenous dissemination, circulating tumor cells interact with different blood components. Thus, there are micro-environmental and systemic processes contributing to cancer regulation. We have published that Red Blood Cells (RBCs) that accompany circulating tumor cells have prognostic value in metastatic breast cancer patients. Although the principal known role of RBCs is gas transport, it has been recently assigned additional functions as regulatory cells on circulation. Hence, to explore their potential contribution to tumor progression, we characterized the proteomic composition of RBCs from 53 breast cancer patients, compared with 33 healthy donors. RBCs from breast cancer patients showed a different proteomic profile compared to healthy donors. The differential proteins were mainly related to extracellular components, proteasome, and metabolism. Besides, LAMP2 emerge as a new RBCs marker with diagnostic and prognostic potential for metastatic patients. Seemingly, RBCs are acquiring modifications in their proteomic composition that probably represents the systemic cancer disease, conditioned by the tumor microenvironment. * Abbreviations : CTCs : circulating tumor cells DTCs : disseminated tumor cells RBCs : red blood cells BC : breast cancer HD : healthy donor HB : haemoglobin EE : extramedullary erythropoiesis MS : mass spectrometry PFS : progression-free survival OS : overall survival M0 : non-metastatic M1 : metastatic