Overexpression and amplification of glutathione S-Transferase pi gene in head and neck squamous cell carcinomas

Human glutathione S-transferase pi (GST-pi) may serve as a useful tumor marker because of the high frequency with which it is found in elevated levels in several tumor types, To determine whether GST-pi is useful as an indicator for cancers of the head and neck, expression of GST-pi mRNA was investigated by Northern analysis in this tumor type, Overexpression of GST-pi mRNA was detected in 9 of 36 (25%) primary head and neck squamous cell carcinomas (HNSCCs), When Southern blot analysis was used to examine the relationship between overexpression and amplification of the GST-pi gene, only 3 of 36 tumors (8%) showed GST-pi gene amplification, Thus, gene amplification is not critical to GST-pi mRNA overexpression in HNSCCs, Moderately and poorly differentiated HNSCCs tended to manifest elevated GST-pi mRNA compared with well differentiated tumors (30% for moderately and poorly differentiated tumors versus none of the well differentiated tumors examined), However, there was no significant correlation between GST-pi mRNA overexpression and clinical stage, T stage (tumor size), N stage (neck nodal status), pathological nodes, or patient survival.