title: Reduced expression of the Syk gene is correlated with poor prognosis in human breast cancer.
abstract: 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.
authors.affiliation: Department of Surgery II, Nagoya City University Medical School, Nagoya 467-8601, Japan. toyamat-ncu@umin.ac.jp
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Toyama
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Iwase
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamashita
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hara
authors.forename: Yoko
authors.initials: Y
authors.lastname: Omoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugiura
authors.forename: Zhenhuan
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Fujii
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D004792:Enzyme Precursors / Q000235:genetics*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009362:Neoplasm Metastasis; D011379:Prognosis; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D000072377:Syk Kinase
chemical_list: D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase