The work aims to present the methods of processing the biological material (of human and animal origin) used in our laboratory in the Department of Biochemistry and Radiobiology of Cancer Disease within the Institute of Oncology Bucharest, for carrying out several biochemical and immunochemical determinations: sialic acid, oxidative stress parameters (products of lipid peroxidation, total thiols, celuloplasin oxidizing activity), immuno-phenotyping, assessment of cell cycle and apoptosis. The biological material provided to our laboratory comes from patients from our clinic, with various types of cancer (blood, urine) and experimental animals: mice, experimental tumour-bearing rats (blood, organs, tumour ascites, and solid tumours). Since the way of processing and preserving biological products has a decisive influence on the results of subsequent determinations, we hope that this work will prove useful and attract the interest of many practitioners in the field. [ABSTRACT FROM AUTHOR]