Correlation between genetic and biological aspects in primary non-metastatic breast cancers and corresponding synchronous axillary lymph node metastasis

This study investigated the changes, if any, in the level of expression of a well defined panel of cell proliferation, differentiation and apoptosis markers between the primary breast tumor and the corresponding synchronous lymph node metastasis from a population of patients with a comparable disease status, in terms of clinical features, and natural history. Ninety pure invasive ductal carcinomas with 10 or more axillary lymph nodes involved and without evidence of distant metastasis were included in this study. Primary tumor and corresponding metastatic lymph node tissue specimens were evaluated for the expression of Cyclin B1, MMP1 metalloproteinase, ICAM-1, RAR beta, Ki67, ER, PgR, p53, bcl-2 and c-erbB2 by immunohistochemistry using standard methods. The bivariate Pearson correlation analysis demonstrated a close relationship between primary and matching corresponding metastatic node. A high grade of correlation has been maintained even when staining results where categorized as positive/negative according to each one marker cut-off level of staining expression. We report the most extensive immunohistochemical analysis of biological determinants in a well defined population of patients with invasive ductal carcinomas and involvement of 10 or more axillary nodes and no distant metastasis. We found a close correlation between the primary tumor and corresponding metastatic node in terms of the expression of all 10 of the markers investigated in this study. The not complete concordance observed could be explained by the gene expression modulation by extrinsic factors and by the microenvironment in which the cancer cells reside.