A) Arrows mark the expression of SFRP-1, CSF-1, MCP-1, NFkB1, MCP-3, Cxcl1, Myd88, Cmkor1, and EMAP-II in the dental follicle cells seen by the oligo DNA microarray. In addition to these putative tooth eruption genes, another 14 genes are seen in the microarray. B) The SFRP-1 gene expression identified in microarray was confirmed in the dental follicle cells (DFC) using RT-PCR. The RNAs of spleen (SP) and thymus (Thy) were also included in the RT-PCR as positive controls.