Clinical significance of aromatase protein expression in axillary node negative breast cancer.
OBJECTIVE
Aromatase catalyzes the conversion of androgens to estrogens; its high expression in breast cancers may be responsible for the local high levels of estrogen and may promote tumor growth and progression; however, the clinical importance of aromatase remains unclear and needs to be further researched.


METHODS
By immunochemistry, we detected aromatase, MMP2 and MMP9 immunoreactivity in 244 axillary lymph node negative breast cancers.


RESULTS
Aromatase immunoreactivity was positively associated with co-expression of MMP2 and MMP9 (MMP2/9) in the estrogen receptor and/or progestin receptor- (ER/PR) positive patients (P < 0.05), but not in the ER and PR negative patients (P > 0.05); aromatase status positively associated with tumor size in the postmenopausal patients (P < 0.05) but not in the premenopausal patients (P > 0.05). The proportional hazards assumption was violated for aromatase status (global test, P < 0.05), and aromatase was an unfavorable prognostic factor for disease-free survival (DFS) (P = 0.04) in multivariate analysis of time-dependent non-proportional Cox regression. In the ER/PR-positive patients, positive aromatase staining was significantly associated with decreased overall survival (OS) (P = 0.04), but there was no such association in the ER and PR negative patients (P > 0.05).


CONCLUSIONS
Our study suggested that local estrogen production by aromatase plays important roles in the growth and invasiveness of breast cancer; tumor aromatase status may be indicative of breast cancer prognosis in some patients.
Lu
Jingsong
J
Department of Breast Surgery, Cancer Hospital/Cancer Institute, Fudan University, 399 Ling-Ling Road, Shanghai 200032, People's Republic of China.
Li
Hecheng
H
Cao
Daocheng
D
Di
Genhong
G
Wu
Jiong
J
Sheng
Kunwei
K
Han
Qixia
Q
Shen
Zhenzhou
Z
Shao
Zhiming
Z
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001141:Aromatase / Q000378:metabolism*; D001943:Breast Neoplasms / Q000201:enzymology* / Q000473:pathology; D002277:Carcinoma / Q000201:enzymology* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000201:enzymology / Q000473:pathology; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D011379:Prognosis; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D016019:Survival Analysis
D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D001141:Aromatase; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9