PLASMA GLUTATHIONE-S-TRANSFERASE P1-1 LEVELS IN PATIENTS WITH HEAD AND NECK SQUAMOUS-CELL CARCINOMA

BACKGROUND. Many tumors contain high amounts of the detoxification enz yme glutathione S-transferase P1-1 (GSTP1-1). Elevated levels of GSTP1 -1 have also been detected in serum and plasma from patients with gast rointestinal, lung, or head and neck tumors. The authors of this repor t evaluated the role of GSTP1-1 as a plasma tumor marker in patients w ith head and neck squamous cell carcinoma (HNSCC) of the larynx, hypop harynx, or oropharnyx and in patients with benign head and neck lesion s (BHNL). METHODS, GSTP1-1 levels were measured in EDTA plasma combine d with ethylenediaminetetraacetic acid using a recently developed sens itive and specific sandwich enzyme-linked immunoadsorbent assay. A nor mal reference level with an upper limit of 21.8 mu g GSTP1-1 per liter of plasma was calculated from results obtained with samples from 230 blood donors. RESULTS. Median GSTP1-1 levels in samples from 53 patien ts with oral/oropharyngeal SCC (10.6 mu g/L; range, 3.7-46.1 mu g/L), 12 patients with hypopharyngeal SCC (11.9 mu g/L; range, 5.2-146.6 mu g/L), and 28 patients with laryngeal SCC (14.4 mu g/L; range, 6.4-141. 5 mu g/L) were significantly elevated when compared with plasma GSTP1- 1 levels in samples from 45 patients with BHNL (8.1 mu g/L; range, 3.3 -32.3 mu g/L; P < 0.0001, P < 0.01, and P < 0.0001, respectively). How ever, only 6 of 53 patients (11%) with oral/oropharyngeal SCC, 1 of 12 patients (81) with hypopharyngeal SCC, and 6 of 28 patients (21%) wit h laryngeal SCC had plasma GSTP1-1 levels above the upper limit of the normal reference level. Thus, only 13 of 93 patients (14%) with HNSCC had elevated plasma GSTP1-1 levels overall. No significant relation b etween plasma GSTP1-1 levels and TNM classification of the tumors was observed. CONCLUSIONS. GSTP1-1 is not a suitable plasma tumor marker f or HNSCC. (C) 1998 American Cancer Society.