Given the propensity of tumors to increase T cell expression of exhaustion markers within the tumor microenvironment, we next interrogated the systemic expression of common exhaustion markers (LAG-3, BTLA, 2B4, PD-1, and TIM-3) on splenic CD4+ T cells at 24 h post-sepsis induction in cancer vs. non-cancer hosts. This evidence concerns the gene BTLA and cancer.