The most important biological behavior of breast cancer is its invasive potential and many efforts was made to reveal the factors related with the invasiveness of breast cancer cells. Some researchers reported that intermediate filament biology could represent an emerging and exciting field in tumor biology with respect to tumor aggressiveness and invasiveness. There are some experimental evidences that co-expression of vimentin, a interfilament marker indicative of mesenchymal lineage, and cytokeratin interfilaments can be correlated with invasiveness and metastatic deposits. So, we tried to determine the role of intermediate filaments such as cytokeratins and vimentin with respect of bone marrow micrometastases.

Expression of cytokeratins 8, 18, 19 and viementin were immunohistochemically evaluated. Detection of bone marrow micrometastases was preformed through RT-PCR targeting mRNA of cytokeratin 19.

In order to compare the study group by the expression extent of cytokeratins, the case expressing 50% or more of observed cells was classified into the case with high expression and the case expressing 49% or less was classified into the case with low expression.

The only cytokeratin of high expression representing the risk of bone marrow micrometastases was cytokeratin 8. Vimentin expression by itself did not show any significance indicating bone marrow micrometastases. However, The cases possesing cytokeratin 8, 18, and 19 expression, altogether 75% or more showed a significantly high risk to bone marrow micrometastases. In that cases, addition of vimentin expression allowed a more higher possibility of bone marrow micrometastases.

A high expression of cytokeratin 8 among cytokeratins was related with bone marrow metastases. However, vimentin expression by itself did not show any realtionship with bone marrow metastases. So, a further study is needed in order to reveal the role of vimentin expression in progression and metastases of breast cancer.