Expression of metallothionein-III in patients with non-small cell lung cancer.

Currently, there is little knowledge concerning expression of metallothionein-III (MT-III), also known as growth-inhibitory factor, in non-small cell lung cancer (NSCLC). In this study, we evaluated MT-III expression in 184 patients using immunohistochemistry and in 61 cases using real-time polymerase chain reaction. MT-III mRNA expression was significantly higher in NSCLC as compared to non-malignant lung tissues (NMLT; p<0.0086). MT-III expression was noted in the cytoplasm and nucleus of cancer cells. Significantly lower nuclear MT-III (p<0.0001) expression and significantly higher cytoplasmic MT-III (p=0.0068) expression was noted in the pneumocytes of NMLT, as compared to NSCLC. Nuclear MT-III expression was significantly higher in G1 cases as compared to G2 (p=0.0308) and G3 (p=0.0194) cases. Low cytoplasmic MT-III expression was associated with larger primary tumour size (p=0.0378). Lower MT-III mRNA and cytoplasmic MT-III expression was associated with poor patient outcome (p=0.0410 and p=0.0347, respectively). MT-III expression may have an impact on the pathogenesis of NSCLC.