The expressions of three X series
Lewis antigens, including Lewis X (Le(x)),
sialyl Lewis X (
SLe(x)) and sialyl dimeric Lewis X (SDLe(x)) were studied with immuno-histochemical methods in human non-small cell
pulmonary cancer (NSCPC) and primary
liver cancer (PLC) with different pathological conditions. The
Lewis antigens are mainly expressed on the cell surfaces, medially or slightly in the cytoplasm, but not in the cell nuclei of the
cancer tissues. The regions adjacent to the
cancer tissues do not express any
Lewis antigens. The positive rates of these
antigens in NSCPC were within the range of 75% to approximately 86%. There was no apparent difference in positive rates between the cases with different differentiation and the presence or absence of
metastasis in peripheral lymph nodes, nor among the three
antigens, except that the positive rate of SDLe(x) was lower (about 56%) in the cases with well/medium differentiation and without
metastasis. However, the expression-intensities (SI indexes) of all three
antigens were significantly higher in the samples of poor differentiation and with
metastasis as compared to those with well/medium differentiation and without
metastasis. The two
sialyl Lewis antigens increased more significantly than non-sialylated Le(x). The expressions of these
antigens were also observed in the peripheral lymph nodes with
metastasis, but not in those without
metastasis. The positive rates of Le(x),
SLe(x) and SDLe(x) in human primary
liver cancer were 83.3%, 88.9% and 77.8%, respectively. In the cases with
cancer cell
thrombosis (CCT) in portal vein (an index of
metastasis), the expressions of all these three
antigens were stronger than those in the cases without CCT.
SLe(x) was the most abundant and most highly increased Lewis
antigen on the surface of NSCPC and PLC, especially in the cases with poor differentiation and
metastasis. In the study of the enzymatic basis of the increased
Lewis antigens in PLC by using Northern blot, it was found that the level of alpha1,3
FucT-III/VI
mRNA in PLC tissues was much higher than that in the adjacent regions, and more significantly higher in the
cancer tissues from patients with CCT in portal vein. In contrast, the expression of alpha1,3 FucT-VII was rather low in
cancer tissues and not different from the adjacent regions in spite of the presence or absence of CCT. These results reveal that the
SLe(x) in PLC is mainly synthesized by alpha1,3
FucT-III/VI (especially VI) and is the most important Lewis
antigen involved in the
metastasis of PLC.