PROGNOSTIC-SIGNIFICANCE OF METHYL-P-HYDROXY-PHENYLLACTATE-ESTERASE ACTIVITY IN LARYNGEAL SQUAMOUS-CELL CARCINOMA

We assayed methyl-p-hydroxyphenyllactate esterase (MeHPLAase) activity in 63 cases of primary laryngeal squamous cell carcinoma. MeHPLAase a ctivity did not show any correlation with oestrogen, progesterone and epidermal growth factor (EGF) receptor levels. No significant relation ship was found between MeHPLAase activity and age, sex, tumour site, T classification, stage of disease and EGFR status, whereas a significa nt inverse relationship was found between enzymatic activity and neck lymph node positivity at presentation. The median value of MeHPLAase a ctivity tended to be higher in tumours with low histopathological grad e than in those with high histopathological grade. During the follow-u p period (median 50 months, range 2-90 months) locoregional recurrence s were observed in 31 out of 63 (49%) cases. At the end of the study, 27 out of 63 (43%) patients had died of cancer. Cox univariate analysi s using MeHPLAase activity as a continuous covariate showed that the l evels of enzymatic activity were inversely associated with the risk of death and relapse. Assuming the mean value of enzymatic activity as t he cut-off value, we found a statistically significant relationship be tween high MeHPLAase activity and longer relapse-free and overall surv ival. MeHPLAase activity status retained its prognostic significance a lso in the lymph node-negative subgroup of patients. On multivariate a nalysis, both EGFR and MeHPLAase activity proved to be independent fac tors for predicting a short relapse and the overall survival.