Metallothionein Electrochemically Determined using Brdicka Reaction as a Promising Blood Marker of Head and Neck Malignant Tumours
Abstract
There are more than half of million patients who fall ill with head and neck carcinoma per year, which 6 % of annually newly diagnosed malignant diseases in the world. Group of head and neck tumours includes tumours occurring in the upper respiratory tract and upper digestive tract.
They include tumours occurring in the area of oral cavity, tumours of hard and soft palate, gingivae and tongue. However, suitable markers in the case of head and neck carcinoma have not been satisfactory identified.
Metallothioneins as a group of proteins with unknown but important role in development of a tumour can be assumed as a potential marker. Therefore, electrochemical monitoring of metallothionein levels in patients suffering from primary malignant tumour in head and neck area and examination of a suitability of electrochemical detection as a technique to be used in clinical practise are the most important aims of this study.
Differential pulse voltammetry Brdicka reaction was optimized (time of accumulation 240 s, dilution of a sample 100 times and sample injection 10 mu l) and used for analysis off blood obtained from 145 patients with newly diagnosed malignant tumour disease in the head and neck area. As a control, fifty eight blood samples were used.
The obtained data enabled us to suggest reference MT level in blood of healthy human within the interval from 0.2 to 0.8 mu M. In the tumour blood samples, the most extend group was represented by patients suffering from oropharyngeal cancer (n = 69, 47.5 %), laryngeal cancer (n = 36, 24.8 %), hypopharyngeal cancer (n = 14, 9.6 %), oral cavity cancer (n = 18, 12.4 %) and rarely occurring nasal cavity and paranasal sinus cancer (n = 4, 2.7 %) and parotid carcinoma (n = 4, 2.7%).
Age median of the studied group was 60 years. Determined MT levels in blood of patients varied from 1.08 to 6.39 mu M, whereas average values differed in the accordance with tumour localization.
Differences between individual localizations are discussed. In conclusion, MT levels are closely associated with the rate of tumour differentiation, stage of tumour disease and tumour cell characteristics.
Our study demonstrates not only changes in blood MT levels in patients suffering from malignant tumour disease in head and neck area, but also suitability of electrochemical techniques for blood analysis.