Role of S100A7 in regulating inflammatory pathways during mammary tumorigenesis

Psoriasin (S100A7) has been shown to be highly expressed in invasive estrogen receptor negative breast cancers. Expression of S100A7 in human breast tumors represents a poor prognostic marker and correlates with lymphocyte infiltration in high-grade morphology. Recent studies have shown that S100A7 downregulation in ERα- cells lines inhibits tumor growth in in vivo mouse model systems. However, not much is known about its mechanisms in regulating breast cancers. We used microarrays to determine the global differential gene expression in S100A7 overexpressing breast cells and vector control cells and found out that most of the genes involved in inflammatory pathways were differentially regulated. S100A7 was sub-cloned into pIRES2-EGFP plasmid which was then transfected into MDA-MB 231 breast cancers cells to select stable cells. Cells transfected with into pIRES2-EGFP only served as vector control. Then microarray analysis was done on these cells to determine the genes which were regulated by S100A7.