Immunohistochemical detection of cell proliferation in gastric carcinomas with the monoclonal antibody Ki-67. A study of 24 cases.

The proliferative activity in 24 gastric carcinomas was determined by an immunohistochemical method using monoclonal antibody Ki-67 (ABC method). Immunostained nuclei were counted by two observers through a Nachet NS 1000 image numeriser. Three grades were defined according to stained nuclei percentage (proliferation index Pi = percentage of cells engaged in cellular cycle outside Go): grade 1 (Pi < 20%); grade 2 (20% < Pi < 40%); grade 3 (Pi > 40%). About 60% of tumours were in grade 1 and 10% in grade 3. No correlations were observed between Pi and the following parameters: histological differentiation; parietal extension; presence or absence of metastasis. These results may be compared to the two other available studies of Ki-67 antibody in gastric cancers. Our study also showed a heterogeneous distribution of immunostained nuclei, within each single tumour and from one tumour to another, which has been noted in one previous study and in a similar one we made on colorectal carcinoma. This heterogeneity is the consequence of the variability of carcinomatous cell proliferative activity; an important biological factor in the evaluation of tumoral process. The proliferative activity in gastric carcinomas provides an estimation of tumour dynamics that might be a prospective criterium for tumoral process evaluation.