Psoriasin (S100A7) expression and invasive breast cancer

Am J Pathol. 1999 Dec;155(6):2057-66. doi: 10.1016/S0002-9440(10)65524-1.


Alteration of psoriasin (S100A7) expression has previously been identified in association with the transition from preinvasive to invasive breast cancer. In this study we have examined persistence of psoriasin mRNA and protein expression in relation to prognostic factors in a cohort of 57 invasive breast tumors, comprising 34 invasive ductal carcinomas and 23 other invasive tumor types (lobular, mucinous, medullary, tubular). We first developed an IgY polyclonal chicken antibody and confirmed specificity for psoriasin by Western blot in transfected cells and tumors. The protein was localized by immunohistochemistry predominantly to epithelial cells, with both nuclear and cytoplasmic staining, as well as occasional stromal cells in psoriatic skin and breast tumors; however, in situ hybridization showed that psoriasin mRNA expression was restricted to epithelial cells. In breast tumors, higher levels of psoriasin measured by reverse transcriptase-polymerase chain reaction and Western blot (93% concordance) were significantly associated with estrogen and progesterone receptor-negative status (P < 0.0001, P = 0.0003), and with nodal metastasis in invasive ductal tumors (P = 0. 035), but not with tumor type or grade. Psoriasin expression also correlated with inflammatory infiltrates (all tumors excluding medullary, P = 0.0022). These results suggest that psoriasin may be a marker of aggressive behavior in invasive tumors and are consistent with a function as a chemotactic factor.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Blotting, Western
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Calcium-Binding Proteins / metabolism*
  • Humans
  • Immunohistochemistry
  • In Situ Hybridization
  • Neoplasm Invasiveness
  • Neoplasm Metastasis
  • Prognosis
  • RNA, Messenger / analysis
  • Reverse Transcriptase Polymerase Chain Reaction
  • S100 Calcium Binding Protein A7
  • S100 Proteins
  • Tumor Cells, Cultured


  • Calcium-Binding Proteins
  • RNA, Messenger
  • S100 Calcium Binding Protein A7
  • S100 Proteins
  • S100A7 protein, human