Plasma and tissue levels of some lanthanide elements in malignant and non-malignant human tissues

Lanthanum (La) levels in plasma, in erythrocyte hemolysate and in tissue from healthy subjects and patients with laryngeal carcinoma were determined by neutron activation analysis. Plasma lanthanum levels were significantly higher in laryngeal carcinomas than in either healthy controls or in subjects suffering from localized inflammation (e.g. epicondylitis of the elbow) (p < 0.001). The mean La concentration in malignant tissue samples was 57.5 ± 7.2 ngg-1 ; the corresponding level in normal adjacent tissue from the same organ was 94.6 ± 12.0ngg-1. This 61% decrease in the concentration of La in malignant tissues was highly significant (p < 0.001). In patients with laryngeal carcinoma we did not observe any detectable level of lanthanum in erythrocyte hemo-lysate; the mean La erythrocyte hemo lysate level in healthy controls and in patients suffering from localized inflammatory condition was 14.3 and 33.2ngml *, respectively. Further studies are in progress to evaluate whether or not this element can serve as a marker for diagnosis or prognosis in cancer.