Determination of metallothionein content in patients with breast cancer, colon cancer, and malignant melanoma
Abstract
Malignant tumours represent a grave illness affecting three out of every ten people in the world. Recently, it has been published that metallothionein (MT), an intracellular high molecular and cysteine-rich protein, which is able to detoxify heavy metals, could serve as a marker of tumour diseases.
Methods: An adsorptive transfer stripping technique (AdTS) in connection with differential pulse voltammetry was used for the determination of metallothionein. Electrochemical measurements were performed with AUTOLAB Analyser (EcoChemie, Netherlands) connected to VA-Stand 663 (Metrohm, Switzerland), using a standard cell with three electrodes.
The Brdicka supporting electrolyte containing 1 mM Co(NH3)6Cl3 and 1 M ammonia buffer (NH3(aq) + NH4Cl, pH = 9.6) was used. Basic biochemical analyses were performed with Advia 1650 and Centaur.
Human blood serum samples were obtained from 27 patients with breast cancer and malignant melanoma in 2005 at the Department of Clinical Biochemistry and Pathobiochemistry, 2nd Faculty of Medicine Charles University, Czech Republic. Each sample was prepared by heat treatment.
Briefly, the sample was kept at 99°C for 15 min., and then cooled to 4°C. The denatured homogenates were centrifuged at 4°C, 15 000 g for 30 min.
Results: We found out that the metallothionein content in human blood serum of patients with breast cancer reached an average of 1.6µM. Moreover, the MT content in nine of the patients was higher than 1 µM (64%) and in three of them higher than 2 µM (21%).
The average MT content in human blood serum of patients with colon cancer was 3.2 µM, thus 2 times higher than in breast cancer patients. Eight patients (88 %) with malignant melanoma had more than 1 µM of MT and 3 of them (33 %) more than 2 µM of MT.
As for patients with malignant melanoma, their average content of MT was 1.97 µmol.dm-3. Higher level of MT was determined in all patients with higher content of liver enzymes.
Moreover, we observed that CA 15-3 tumour marker levels corresponds well with the MT content. Conclusion: It is evident that it is possible to use the electroanalytical techniques for determination of MT in blood serum samples of patients with tumour diseases.
We found out that MT content markedly increases in all studied blood serum samples of the patients with breast cancer, colon cancer, and malignant melanoma.