University of Texas M.D. Anderson Cancer Center
Enzyme May Play Role in Worsening Immune Function in Lung Cancer
Immune cells can keep a cancer from growing, and evading the immune system is a key step in cancer development. An essential amino acid called tryptophan is needed by immune cells. Depletion of tryptophan or accumulation of its breakdown products can lead to impaired immune cell function, and therefore faster tumor growth and poorer prognosis. Lung cancer cells metabolize tryptophan using an enzyme called kynureninase (KYNU). Lung cancers showing high levels of KYNU have worse outcomes. We will study whether lung cancers showing high levels of KYNU have worse outcomes because the depletion of tryptophan and accumulation of its breakdown products lead to worse immune function. We will also look for a sign of KYNU activation in the blood, which may be a marker for patients with more aggressive cancers. Since we believe these cancers are evading the immune system, our research may lead to therapy to reactivate the immune system that is more effective in these lung cancer patients.