The present disclosure relates to therapeutic methods and medical uses comprising the identification and use of cancer marker surrogates for increased polyamine expression. These markers may be used to identify patients who may be treated for diseases and disorders that are susceptible to polyamine synthesis inhibitors, and they can also be used to monitor therapeutic responses when such agents are used. More specifically, reduced levels of let-7 miRNA and elevated levels of LIN28 and HMGA2 proteins were found to correlate with elevated levels of polyamines and may be used for predicting the efficacy of cancer therapy us ing an ornithine decarboxylase (ODC1) inhibitor such as eflornithine (DFMO), suitably in combination with an NSAID such as sulindac.