Ferromagnetism in two mouse tumours

A variety of living organisms has been found recently that are biochemically able to precipitate the ferromagnetic mineral magnetite (Fe3O4). Originally discovered in the radular teeth of a primitive marine mollusc (Lowenstam, 1962), magnetite has since been reported in bacteria (Frankel, Blakemore & Wolfe, 1979), arthropods (Gould, Kirschvink & Deffeyes, 1978), and vertebrates (Walcott, Gould & Kirschvink, 1979; Zoeger, Dunn & Fuller, 1981; Walker & Dizon, 1981). Although the presence and biological origin of this material are clear, very little is yet known about the distribution or metabolic function of ferromagnetic minerals in vertebrate tissue. Magnetic remanence, which uniquely indicates the presence of ferromagnetic particles, has been previously detected in localized areas associated with the dura membranes of homing pigeons (Walcott et al. 1979) and dolphins (Zoeger et al. 1981), in pigeon neck muscles (Presti & Pettigrew, 1980), in the mid-brain of monkeys, and in human adrenal glands (Kirschvink, 1981). We report here the first discovery of anomalously high concentrations of ferromagnetic material in two strains of neoplasms, YC-8 lymphoma and Lewis lung tumour, as well as the apparent absence of such material in three human carcinomas (gastric, colon and renal)