Expression data from fine-needle aspiration biopsies of breast cancer metastases from different anatomical sites

To determine whether breast cancer molecular subtypes and tumor characteristics with demonstrated significance in a primary tumor setting can also confer clinically relevant information in breast cancer metastases. We assessed previously published gene expression modules of seven biological processes and the intrinsic subtypes (PAM50). The translational aspect of the Swedish randomized TEX trial included 112 patients with at least one biopsy from morphologically confirmed loco-regional or distant breast cancer metastasis diagnosed from December 2002 until June 2007. All patients had detailed clinical information, complete follow-up and metastasis gene expression information (Affymetrix array GPL10379). We performed global gene expression profiling on fine-needle aspirates of metastatic lesions from different anatomical sites obtained from breast cancer patients treated within the Swedish randomized trial (TEX) of first-line chemotherapy for locally advanced or metastatic breast cancer. Samples were collected before commencement of treatment.