Comparability of gene expression in human blood, immune and carcinoma cells

The tissue-specific pattern of gene expression can provide important clues for clinical diagnosis and prognosis. Though high-density microarray technology offers the opportunity to examine patterns of mRNA expression on a genomic scale, accessible tissue is still a problem. We conducted secondary data analysis on transcriptional profiles of 79 human tissues using Affymetrix U133a microarrays. We found that expression among tissues belonging to the central nervous system shows distinctly similar patterns. The organ-free immune cells in peripheral blood are more comparable with leukemia/lymphoma at the transcriptome level, and differential co-expression patterns appear between tissue groups of organ-free immune and leukemia/lymphoma cells.