Expression of glutathione-S-transferase-pi in human tumours.

Expression of glutathione-S-transferase-pi (GST-pi) gene was quantitatively analysed on various human tumours (renal cell, colorectal, head and neck, ovarian carcinomas, soft tissue sarcomas; non-Hodgkin lymphomas) and on the corresponding normal tissues when available (kidney, colorectum and head and neck). GST-pi mRNA expression level was found to be significantly higher in tumours (P less than 0.01) than in the normal counterparts (mainly 7.3, 3.5- and 3.0-fold in colorectal, head and neck, and renal carcinomas, respectively). Most tumours displayed a significant relationship between higher GST-pi expression level and poor differentiation grade of tumour cells, thus suggesting a relationship between GST-pi activity, neoplastic transformation and cellular differentiation grade. The high requirement of GST-pi activity neoplastic cells displayed was not singularly related to cellular replication rate. Finally, GST-pi gene expression levels were not affected by chemotherapeutic treatments.