Metallothionein in human lung carcinoma

Abstract

Eleven pairs of surgically resected lung cancers and corresponding non-neoplastic lung tissue were evaluated for metallothionein (MT) and metal content (cadmium and copper) by the heme/109Cd binding assay and atomic absorption spectroscopy, respectively. Tissue samples, obtained from patients ranging in age from 51 to 79, included six adenocarcinomas, two small cell carcinomas, one mixed cell carcinoma, one squamous cell carcinoma, and one carcinoma of non-primary origin (i.e., melanoma). Paired t-tests showed that metallothionein and copper concentrations in lung tumor tissue were significantly elevated when compared to non-malignant lung tissue. Cu was the major metal associated with the 10 kDa MT fraction in lung tumors whereas Cd was the primary metal bound to MT from non-neoplastic lung tissue. Since Cu-thionein is also known to be elevated in fetal lung tissue, the possibility exists that MT might represent an oncodevelopmental product which is useful as a biomarker for the early detection of lung carcinoma.