CD44 and breast neoplasm: demonstrated that tryptophan catabolism contributes to the depletion of T cells, underscoring the impact on immune evasion by tumors.[80] Another study indicated that KYNU could underpin the breast tumor cell invasion through the CD44 axis.[81] Consistent with previous studies, findings from our metabolic flux analysis emphasize the potential of targeting and/or disrupting this metabolic pathway (tryptophan catabolism) through the KYNU gene thereby circumventing the immune evasion and improving the overall patient outcome.