Sialic acid changes in Dalton's lymphoma-bearing mice after cyclophosphamide and cisplatin treatment.

Sialic acid changes in Dalton's lymphoma cells and other tissues of 10-12-week-old Swiss albino mice were investigated in relation to tumour growth in vivo and following cyclophosphamide (ip, 200 mg/kg body weight) or cisplatin (ip, 8 mg/kg body weight) treatment. Three to four animals of both sexes were used in each experimental group. The sialic acid level of tumour cells (0.88 micromol/g) increased with tumour progression (1.44-1.59 micromol/g; P < or =0.05) in mice. Sialic acid concentration in other tissues (liver, kidney, testes and brain) also increased (approximately 40, 10, 30 and 58%, respectively) in the tumour-bearing hosts as compared with that in the respective tissues of normal mice. In vivo cyclophosphamide or cisplatin treatment resulted in an overall decrease of sialic acid contents in the tissues. Cyclophosphamide was more efficient in lowering tissue sialic acid than cisplatin (P < or =0.01, ANOVA). It is suggested that sialic acid residues could be an important factor contributing to the manifestation of malignant properties in cancer cells in general and Dalton's lymphoma cells in particular. A significant decrease in the sialic acid content of Dalton's lymphoma cells after cisplatin or cyclophosphamide treatment may bring about specific changes in tumour cells which could be associated with tumour regression.