CXCR4 and neoplasm: Furthermore, COUP-TFI mRNA expression is significantly higher in grade 1 (but not in grade 2 or 3) tumors than in normal breast tissue and that CXCR4 mRNA is significantly higher in cancerous tissue than in normal breast tissue and its expression is increasing with tumor grade, whereas transcripts of CXCL12 was significantly decreased in all the tumor grades compared to normal tissues (119).