Study Population: 78 patients with NSCLC (n=39 squamous cell (SQ), and n=39 adenocarcinoma (AC) tumors) metastatic to the brain to compare with published microarray studies of non-metastatic NSCLC patients with these tumor types as well as with one another to help explain the differential trend toward metastasis in some patients with NSCLC and not others, as well as the differential trend to brain metastasis in the AC subtype.