Quantitation of endogenous lectin expression in 3LL tumors, growing subcutaneously and in the kidneys of mice.

By means of microdensitometry and image analysis, quantitative measurements were compared of endogenous lectin expression in tissue sections from 3LL carcinomas growing in the subcutis and kidneys of mice following the direct injection of cancer cells. The lectins were visualized by means of a modification of the ABC-peroxidase technique. In comparison with the subjective, visual inspection of similar materials reported previously, these quantitative techniques not only confirmed, but also provided additional information on site-associated changes in 3LL cell populations. Previously, 2 classes of cancer cells were recognized within the tumors on the basis of staining intensity, compared with 3 classes in the present study and, in addition, the relative areas occupied by these 3 densitometric classes were determined by image-analysis. Both "low" and "high" integrated intensities were significantly greater in the kidney tumors in 11 of 24 cases, and in 6 of 24 cases of s.c. tumors. The areas occupied by "high" and "low" intensity cells were significantly higher in 14 of 24 kidney tumors, and in 2 of 24 s.c. tumors. The results indicate often marked differences in endogenous lectin expression, between 3LL cancer cells from a common source, after direct delivery and growth in 2 different anatomic sites. These results indicate the necessity of taking into account analogous changes, when comparing these and other properties of cancer cell populations in metastases with those in primary tumors, with respect to both the generation of site-associated differences and their possible site-associated abrogation.