Biologic markers in breast cancer: An update

Abstract

The ability to diagnosis breast cancer at an earlier stage and the development of a wider range of treatment options have stimulated the search for more refined criteria to select the subgroup of patients who develop recurrent disease despite the absence of nodal involvement at the time of tumor resection. Such criteria include biologic parameters of prognostic relevance, especially those that can be applied to routinely processed tissue sections, as they allow a correlation with established histologic features of prognostic relevance. The biologic parameters can be divided into those which are intrinsic characteristics of the tumors cells and those related to the interaction of tumor and the immediate microenvironment, the latter factors influencing invasiveness and metastatic potential. Steroid hormone receptor expression, tumor growth fraction estimation, growth factors and their receptors, and tumor suppressor gene proteins can now be assessed by immunostaining of routinely processed tissue sections. Whereas the assessment of other parameters such as bcl-2 and Bax proteins, nm23 metastasis suppressor gene expression, vimentin, and other genes related to cyclin- dependent kinase activity can also he done immunohistochemically, their worthiness as prognostic parameters require further studies. Factors related to tumor-stromal interaction include angiogenesis, adhesion molecules, cytoskeletal proteins, extracellular matrix proteins and proteases, all of which are potentially useful prognostic indices and also hold promise for newer avenues of therapeutic intervention.