COMPARATIVE ANALYSES OF BONE-MARROW MICROMETASTASES IN BREAST AND GASTRIC-CANCER

This study is a comparative analysis of the prevalence, absolute numbe r and aggregation status of bone marrow micrometastases (BMM) between breast (n = 234) and gastric (n = 102) cancer patients based on a stan dardized number of 1 x 10(6) bone marrow-derived cells per patient. Ad ditionally, expression of the epithelial cell adhesion molecule E-cadh erin was analyzed on disseminated tumor cells. A positive BMM status w as demonstrated in 88/234 breast and 45/102 gastric cancer patients. T he presence of CK18(+) cells positively correlated with parameters of advanced tumor progression in breast, but not in gastric cancer. Inter estingly, 25.2% of the nodenegative patients already had micrometastat ic cells in the bone marrow at diagnosis. Regarding the absolute numbe r of CK18(+) cells and the frequency of CK18(+) cell clusters, no sign ificant difference was found between the 2 tumor types. However, clust ers consisting of more than 10 CK18(+) cells (type II clusters) were p resent exclusively in breast cancer patients. Additionally, co-express ion of CK18 and E-cadherin was detectable in 15/21 micrometastases-pos itive breast but in only 1/9 gastric cancer patients. While prevalence of micrometastatic cells in bone marrow is discussed as an early indi cator for systemic disease, aggregation status and a certain antigen p rofile might be indicative for site-specific differences in the manife station pattern of solid metastases. (C) 1996 Wiley-Liss, Inc.