Expression and clinical significance of matrix metalloproteinase-9 in lymphatic invasiveness and metastasis of breast cancer.
BACKGROUND
Matrix metalloproteinase 9 (MMP-9) is a type-IV collagenase that is highly expressed in breast cancer, but its exact role in tumor progression and metastasis is unclear.


METHODS
MMP-9 mRNA and protein expression was examined by real-time reverse transcriptase PCR and immunohistochemical staining, respectively, in 41 breast cancer specimens with matched peritumoral benign breast epithelial tissue and suspicious metastatic axillary lymph nodes. Lymph vessels were labeled with D2-40 and lymphatic microvessel density (LMVD) was calculated. Correlation of MMP-9 protein expression with clinicopathological parameters and LMVD was also evaluated.


RESULTS
MMP-9(+) staining in breast cancer specimens (35/41, 85.4%) was higher than in matched epithelium (21/41, 51.2%; P<0.05) and lymph nodes (13/41, 31.7%; P<0.001). Higher MMP-9 mRNA expression was also detected in tumor specimens compared with matched epithelial tissues and lymph nodes (P<0.05). Elevated MMP-9 expression was correlated with lymph node metastasis and LMVD (P<0.05).


CONCLUSIONS
MMP-9 was overexpressed in breast cancer specimens compared with peritumoral benign breast epithelium and lymph nodes. Moreover, its expression in the matched epithelium and lymph nodes was positively associated with lymph node metastasis, and its expression in lymph nodes was positively associated with lymphangiogenesis in breast cancer. Thus, MMP-9 is a potential marker for breast cancer progression.
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Qiu-Wan
QW
Wu
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Qing-Mo
QM
Yang
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Yu-Fan
YF
Huang
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Hong-Qiang
HQ
She
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Jing
J
Liang
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Qiao-Lu
QL
Yang
Xiamen Cancer Center and Department of Breast Surgery, The First Affiliated Hospital of Xiamen University, Xiamen, China.
Zhi-Ming
ZM
Zhang
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D042601:Lymphatic Vessels / Q000473:pathology; D020780:Matrix Metalloproteinase 9 / Q000235:genetics* / Q000378:metabolism; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D012333:RNA, Messenger / Q000235:genetics
D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D020780:Matrix Metalloproteinase 9