title: [Expression of SM22α and its relationship with lymph node metastasis in breast cancer].
abstract: OBJECTIVE
  to analyze the relationship between the expression of SM22α and the lymph node (LN) metastasis of breast cancer and to investigate its molecular mechanisms.
  
  
  METHODS
  reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect the expression of SM22α in breast cancer tissue and adjacent normal breast tissue. RT-PCR and Western blot were employed to investigate the SM22α mRNA and protein level in tissues of breast fibroadenoma, breast cancer without LN metastasis and breast cancer with LN metastasis. RT-PCR and zymography were used to detect the MMP2 and MMP9 expression and activity and TIMP1 expression level in breast fibroadenoma, breast cancer samples without LN metastasis and those with LN metastasis respectively.
  
  
  RESULTS
  the expression level of SM22α mRNA in breast cancer was significantly lower than that in breast fibroadenoma or adjacent normal breast tissue (5.1% ± 2.4% vs 15.1% ± 5.3% vs 30.1% ± 5.1%, P < 0.01). The protein and mRNA expression level of SM22α in breast cancer samples with LN metastasis were significant lower than those of breast cancer without LN metastasis (6.2% ± 3.1% vs 10.1% ± 4.1%, P < 0.01). Both the expression and activity of MMP2 and MMP9 in breast cancer samples with LN metastasis were significant higher than those without LN metastasis (P < 0.01). A strong negative correlation was found between SM22α protein level and MMP2 activity (r = -0.848; n = 27; P < 0.01) or MMP9 activity (r = -0.916; n = 27; P < 0.01) in breast cancer tissue.
  
  
  CONCLUSIONS
  a down-regulation of SM22α in breast cancer is correlated with LN metastasis. SM22α may inhibit the LN metastasis through a negative regulation of MMP2 and MMP9 in breast cancer.
authors.affiliation: Department of Oncology, Affiliated Hospital of Hebei University, Baoding 071000, China.
authors.forename: Zhen-feng
authors.initials: ZF
authors.lastname: MA
authors.forename: Nai-peng
authors.initials: NP
authors.lastname: CUI
authors.forename: Jian-hong
authors.initials: JH
authors.lastname: SHI
authors.forename: Huai-ying
authors.initials: HY
authors.lastname: WANG
authors.forename: Shao-hui
authors.initials: SH
authors.lastname: SHI
authors.forename: Ming
authors.initials: M
authors.lastname: WEN
authors.forename: Zhong
authors.initials: Z
authors.lastname: LI
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis / Q000473:pathology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism*; D009124:Muscle Proteins / Q000378:metabolism*; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D008840:Microfilament Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C051615:transgelin; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9