Glutathione S-transferase pi levels in a panel of lung cancer cell lines and its relation to chemo-radiosensitivity.

The human placental form of glutathione S-transferase pi (GST-pi) was measured by a sandwich enzyme-linked immunosorbent assay in lung cancer cell lines established in our laboratories. In classic-type small cell lung cancer (SCLC), variant-type SCLC and non-small cell lung cancer (NSCLC), the respective mean GST-pi values were 0.83 +/- 0.88, 3.27 +/- 2.85 and 2.40 +/- 0.76 micrograms/mg protein. Cell lines with high GST-pi content had low levels of neuron specific enolase, which is known as a representative tumor marker for SCLC. This suggests that GST-pi may also be used as a potential marker for NSCLC. The lines with low GST-pi content were more sensitive to radiation than those with high GST-pi content. Cell lines not subjected to prior therapy also showed a good correlation between GST-pi levels and chemosensitivity to cisplatin. The findings suggest that GST-pi can be used as an adjunctive marker for lung cancer.