Reduced expression of the Syk gene is correlated with poor prognosis in human breast cancer

Cancer Lett. 2003 Jan 10;189(1):97-102. doi: 10.1016/s0304-3835(02)00463-9.


Syk is a non-receptor type of protein-tyrosine kinase that is widely expressed in hematopoietic cells. Syk expression has been reported in breast tissue. However, the function of Syk in breast tissue remains unclear. In 25 (28%) of the 90 paired samples of human breast cancer and the matched, adjacent non-cancerous tissues examined here, reduced mRNA expression of Syk in the breast cancer tissues was observed by real-time quantitative reverse transcription-polymerase chain reaction. Eight (32%) of the 25 cases showing reduced Syk mRNA expression demonstrated distant metastasis of breast cancer, while only 4 (6%) of the 65 cases who did not show reduced Syk expression had distant metastasis. Kaplan-Meier curves demonstrated that patients with reduced Syk expression were at significantly increased risk for distant metastasis (P=0.0003). Our data suggest that reduced Syk expression in breast cancers is associated with distant metastasis and poor prognosis; therefore, Syk is considered to be a potential tumor suppressor and anti-metastasis gene in human breast cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Breast Neoplasms / genetics*
  • Enzyme Precursors / genetics*
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Neoplasm Metastasis
  • Prognosis
  • Protein-Tyrosine Kinases / genetics*
  • Syk Kinase


  • Enzyme Precursors
  • Intracellular Signaling Peptides and Proteins
  • Protein-Tyrosine Kinases
  • SYK protein, human
  • Syk Kinase