Gene profiling provides a multitude of data on individual gene expression. The view is expressed here that unreplicated data can be used in a descriptive way to compare cell populations in terms of their lineage characteristics and function. In these studies, the aim is to provide a snapshot of gene expression or its absence as a reflection of cell lineage or type, rather than gain a reliable expression measure for all genes expressed. The data set used in this analysis represents gene expression in the splenic stroma STX3 supportive of dendritic cell hematopoiesis and the lymph node stroma 2RL22, which is non-supportive. These were obtained by hybridization of Affymetrix U74Av2 genechips. The use of P-value selection to identify genes with a high probability of differential expression has been used effectively to detect differentially expressed genes. Genes that relate to a niche environment for hematopoiesis have been selected for further study to make predictions about the cell types of supportive stroma.