title: Depletion of cell surface CD44 in nonmelanoma skin tumours is associated with increased expression of matrix metalloproteinase 7.
abstract: BACKGROUND
  Expression of matrix metalloproteinase (MMP)-7 and MMP-9 is low in the normal epidermis and is induced by physiological processes such as wound healing, but also malignant transformation of epidermal cells. The activity of both MMPs has been associated with the hyaluronan (HA) receptor CD44. We previously reported that the levels of CD44 and HA differ between the two types of epidermal tumours, basal (BCC) and squamous cell carcinoma (SCC), as well as between different grades of SCC.
  
  
  OBJECTIVE
  To investigate if the immunostaining patterns of MMP-7 and MMP-9 correlate to those of CD44 and HA in BCC and SCC.
  
  
  METHODS
  Paraffin sections from 71 BCCs, 21 in situ SCCs and 27 SCCs were immunostained for MMP-7 and -9.
  
  
  RESULTS
  Positive immunostaining for MMP-7 and MMP-9 was found in tumour cells of both BCC and SCC, while the staining intensity tended to be stronger in SCC. The staining intensity of MMP-7 was inversely correlated with that of CD44 in both tumour types. In well-differentiated SCC, the intensity of MMP-7 was generally weak, while CD44 staining was strong and homogeneously distributed. In poorly differentiated SCC, an increase in MMP-7 was seen, and the staining intensity of CD44 became weak and was locally absent. No correlation was seen between MMP-9 and CD44 or either of the two MMPs and HA.
  
  
  CONCLUSIONS
  Our results show that in nonmelanoma skin tumours MMP-7 and -9 are present in the tumour cells, and suggest a link between MMP-7 activity and the depletion of cell surface CD44.
authors.affiliation: Department of Biomedicine/Anatomy, University of Kuopio, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Hartmann-Petersen
authors.forename: R H
authors.initials: RH
authors.lastname: Tammi
authors.forename: M I
authors.initials: MI
authors.lastname: Tammi
authors.forename: V-M
authors.initials: VM
authors.lastname: Kosma
mesh_terms: D002280:Basal Cell Carcinoma / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis*; D020783:Matrix Metalloproteinase 7 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D012878:Skin Neoplasms / Q000378:metabolism*; D013223:Statistics as Topic
chemical_list: D018960:Hyaluronan Receptors; D009363:Neoplasm Proteins; D020783:Matrix Metalloproteinase 7; D020780:Matrix Metalloproteinase 9