title: Down-regulation of S100A2 in lymph node metastases of head and neck cancer.
abstract: BACKGROUND
  Our cDNA microarray analysis of squamous cell carcinoma of the head and neck (SCCHN) previously identified that S100A2 was down-regulated in highly metastatic 686LN-M3s cell lines established through in vivo selection using a metastatic xenograft mouse model. S100A2, a putative tumor suppressor, has been found to be down-regulated in several types of primary tumor as compared with the normal tissue. Only a few reports have explored its expression status and function in metastasis.
  
  
  METHODS
  To further confirm down-regulation of S100A2 in human metastasis, we examined S100A2 expression using immunohistochemical analysis of paraffin-embedded SCCHN tissues. The samples included primary SCCHN tumors (Tu-1) and involved lymph nodes (Met-1) from the same patients, and primary tumors in node-negative patients (Tu-2).
  
  
  RESULTS
  Most of these tumors expressed S100A2 but lymph node metastases showed a pattern of reduced staining for S100A2 compared with primary tumors. A similar expression pattern of S100A2 was also observed in several SCCHN cell lines by reverse transcription-polymerase chain reaction (RT-PCR) and immunoblotting. Particularly, S100A2 expression was lower in 686LN than Tu686 and hardly detectable in the metastatic derivatives 686LN-M3s. Further study of S100A2 promoter showed higher methylation intensity in these metastatic derivatives than in Tu686 and 686LN.
  
  
  CONCLUSIONS
  S100A2 was down-regulated in lymph node metastasis of SCCHN, suggesting that instead of being a putative tumor suppressor, S100A2 may play a role in the metastasis of SCCHN.
authors.affiliation: Department of Hematology and Oncology, Winship Cancer Institute, Emory University, Atlanta, Georgia, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Hunt
authors.forename: Dong M
authors.initials: DM
authors.lastname: Shin
authors.forename: Zhuo Georgia
authors.initials: ZG
authors.lastname: Chen
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D002454:Cell Differentiation / Q000502:physiology; D002630:Chemotactic Factors / Q000378:metabolism*; D018899:CpG Islands / Q000502:physiology; D018450:Disease Progression; D015536:Down-Regulation; D005260:Female; D006258:Head and Neck Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis / Q000503:physiopathology*; D008297:Male; D008745:Methylation; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009418:S100 Proteins / Q000378:metabolism*
chemical_list: D002630:Chemotactic Factors; D009418:S100 Proteins; C098997:S100A2 protein, human