An N-methyl derivative of the antineoplastic antibiotic mitomycin C isolated from the bacterium Streptomyces ardus and other Streptomyces bacterial species. Bioreduced porfiromycin generates oxygen radicals and alkylates DNA, producing interstrand cross-links and single-strand breaks, thereby inhibiting DNA synthesis. Porfiromycin is preferentially toxic to hypoxic cells. or A substance that is being studied in the treatment of cancer. It belongs to the family of drugs called anticancer antibiotics.