Fast protein liquid chromatography (FPLC) of leukaemic cell N-acetyl beta-D hexosaminidases

Diagnostic differentiation of chronic B-cell malignancies using monoclonal antibody L161 (CD1c)

The expression of membrane CD1c, as defined by monoclonal antibody L161, was examined on malignant lymphoid cells from 191 cases of chronic lymphoproliferative disease and on eight 'normal' enriched tonsil B-cell extracts. Of 79 cases of chronic lymphocytic leukaemia (CLL) studied, 77 showed low (less than 20% positive cells) CD1c expression whereas 63/71 (89%) cases of B-PLL, HCL and B-NHL showed increased CD1c+ (but not CD1a or CD1b) components. In contrast, malignancies corresponding to terminal stages of B-cell differentiation (immunocytoma and myeloma) generally showed low CD1c expression as did lymphoid cells from 10 cases of post-thymic malignancy. Although there was some correlation between the expression of membrane CD1c and immunoglobulin (SIg) light chain densities (P less than 0.001), it is relevant in diagnostic terms that seven cases of B-NHL with low SIg staining intensities more typically associated with CLL were CD1c+. CD1c expression was not, however, correlated with the presence of CD23 or FMC7 determinants but did show a similar pattern of expression to that previously reported for beta-2 microglobulin. Determination of cellular CD1c by APAAP immunocytochemistry confirmed the presence of higher antigen densities in malignant B-cells at intermediate/late stages of differentiation and this interpretation was further supported by the finding that the majority of phenotypically mature tonsil B-cells were also CD1c+. The determination of CD1c expression by malignant B-cells may therefore be of particular value in the diagnostic differentiation of chronic lymphoproliferative disorders.

Malignant cell glycoproteins and glycolipids

The cell surface is involved in cell growth and division, cell-cell interaction, communication, differentiation and migration, and other processes likely to be involved in malignant transformation and/or the metastatic spread of cancer. Although there are many alterations of glycoproteins and glycolipids on the malignant cell surface, it is unclear whether these alterations are epiphenomena or an integral part of the malignancy process. This article reviews the recent literature and some earlier studies relevant for understanding emerging concepts and trends with respect to malignant cell glycoconjugates. Emphasis is on structural alterations of the carbohydrate portions of malignant cell glycoproteins and glycolipids and on the enzymes (glycosyltransferases and glycosidases) involved in their metabolism. Practical applications derived from malignant cell glycoconjugate studies are discussed briefly with respect to the diagnosis, staging, monitoring, and treatment of malignant disease. The review concludes by indicating which research areas on malignant cell glycoconjugates are likely to be fruitful in increasing our basic understanding of, and ability to deal effectively with, malignant disease.