Tumors supply cancer cells with free cysteine from a reduced microenvironment
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A bioRxiv preprint posted on 27 October 2026 reports that the tumor microenvironment is chemically reduced, allowing cancer cells to acquire cysteine directly rather than relying on cystine. Researchers compared tumor interstitial fluid, matched healthy organs, and serum across three mouse cancer models. Tumor interstitial fluid was in a reduced state, with free cysteine exceeding cystine, and cystine was nearly absent in lung tumor interstitial fluid. Lung cancer cells imported cysteine and cystine with comparable efficiency and could proliferate on cysteine alone. Glutathione in the tumor microenvironment helped keep cysteine in its reduced form through disulfide exchange. The findings have not yet undergone peer review, and confirmation in human tumors is still an open question.
Written by a model from the reports · updated 2 hours ago
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- biorxiv.orgCancer cells acquire cysteine directly from a reduced tumor microenvironment
The study compared tumor interstitial fluid, matched healthy organs, and serum across three mouse cancer models, finding that tumor interstitial fluid is in a reduced state, with free cysteine exceeding cystine, and cystine nearly absent in lung tumor interstitial fluid. Lung cancer cells take up cysteine and cystine with comparable efficiency and can proliferate on cysteine alone; glutathione in the tumor microenvironment helps keep cysteine reduced through disulfide exchange.
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