Simultaneous detection of intercellular adhesion molecules-1 (ICAM-1) and
carcinoembryonic antigen (CEA) was investigated in AMeX (
Acetone,
Methyl benzoate and
Xylene)-fixed,
paraffin-embedded
tumor sections of 24
adenocarcinomas of the lung, using the
avidin-
biotin-
peroxidase complex (ABC) method. Distinct expression of both
ICAM-1 and CEA was found in
tumor cells in all cases. The staining pattern of these two
antigens was quite similar and was mainly affected by the
tumor grade. In well-differentiated
adenocarcinoma, uniformly positive staining was demonstrated predominantly along the apical surfaces of the
tumor cell nests, and to a lesser degree on the lateral cell surface and in the cytoplasm with apical concentration, but no positive staining was found on the basal cell surfaces. In poorly differentiated
adenocarcinoma, positive staining was found along the entire cell surface and in the cell cytoplasm without any apical concentration, and the staining intensity varied from region to region in the same
tumor cell and from cell to cell within the same
tumor cell nest. In moderately differentiated
adenocarcinoma, the staining pattern was intermediate between those of well and poorly differentiated
adenocarcinoma with some degree of apical concentration. The expression pattern of
ICAM-1 or CEA on
tumor cells did not correlate well with stromal inflammatory cell infiltration. These results indicate that the expression pattern of CEA and
ICAM-1 is an inherent characteristic of
tumor cells, and that their abnormal expression may play an important role in the physiological behavior of
tumor cells because the polarity of their expression is lost in parallel with histological
tumor grades.