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.
Keywords: Methioninase; PSA; methionine addiction; oral; patients; prostate cancer; response.