Prostate Cancer–Associated Gene Expression Alterations Determined from Needle Biopsies. Homo sapiens

To accurately identify gene expression alterations that differentiate neoplastic from normal prostate epithelium using an approach that avoids contamination by unwanted cellular components and is not compromised by acute gene expression changes associated with tumor devascularization and resulting ischemia. Overall design: Approximately 3,000 neoplastic and benign prostate epithelial cells were isolated using laser capture microdissection from snap-frozen prostate biopsy specimens provided by 31 patients who subsequently participated in a clinical trial of preoperative chemotherapy. To eliminate potential dye bias, we randomly alternated Cy3 and Cy5 labeling to neoplastic and benign epithelium across 31 samples. Labeled cDNA probes were hybridized in a head-to-head fashion, normal versus neoplastic from the same individual, to custom-made microarrays composed of 6,200 clones derived from the Prostate Expression Database.