(acetaldehyde), tumors help contain the resulting ROS and prevent systemic damage.
Just as the liver uses ADH and ALDH to convert ethanol to acetaldehyde and then to acetate for safe clearance, many tumors upregulate the same enzymes to intercept and process ethanol locally within the tumor compartment, helping to contain the toxin when the liver is overwhelmed.
(3) Estrogen
Even estrogen follows this pattern. When in excess (from obesity, exogenous hormones, and xenoestrogens), estrogen creates ROS and behaves as a toxin that the liver must process. When the liver’s capacity to clear excess estrogen is exceeded, estrogen-sensitive tumors upregulate estrogen receptors and the full suite of Phase I and Phase II detox enzymes.
The tumor becomes a localized backup unit that sequesters and metabolizes estrogen, limiting the circulation of reactive catechol estrogen metabolites that generate widespread oxidative stress.