PT - JOURNAL ARTICLE AU - QINGHONG HAN AU - ROBERT M. HOFFMAN TI - Lowering and Stabilizing PSA Levels in Advanced-prostate Cancer Patients With Oral Methioninase AID - 10.21873/anticanres.14958 DP - 2021 Apr 01 TA - Anticancer Research PG - 1921--1926 VI - 41 IP - 4 4099 - http://ar.iiarjournals.org/content/41/4/1921.short 4100 - http://ar.iiarjournals.org/content/41/4/1921.full SO - Anticancer Res2021 Apr 01; 41 AB - Background/Aim: Methionine addiction is a general and fundamental hallmark of cancer due to the excess use of methionine for transmethylation reactions, termed the “Hoffman Effect”. Methionine addiction has been shown to be a highly-effective target for cancer therapy by methionine restriction with oral recombinant methioninase (o-rMETase) in preclinical studies, including patient- derived orthotopic xenograft (PDOX) mouse models of cancer. A clinical study of o-rMETase as a supplement showed a 70% reduction of PSA levels in a patient with bone-metastatic prostate cancer. Materials and Methods: In the present study, two advanced prostate-cancer patients took o-rMETase as a supplement for approximately one month. Results: One of the patients taking o-rMETase showed a 38% reduction of PSA levels and the second patient showed a 20% PSA reduction. Conclusion: o-rMETase shows promise for treating patients with advanced prostate cancer.