Role of stromal myofibroblasts in invasive breast cancer: stromal expression of alpha-smooth muscle actin correlates with worse clinical outcome.
BACKGROUND
Recently, the desmoplastic reaction has been implicated as having an important function in epithelial solid tumor biology. There have been no reports showing the relativity of invasive breast cancer and the desmoplastic reaction by a quantitative analysis of the myofibroblasts that were an important player in the desmoplastic reaction. The purpose of this study was to immunohistochemically investigate the correlation between the desmoplastic reaction and the clinicopathology of invasive breast cancer.


METHODS
The study included 60 patients with a known prognosis of invasive breast cancer. We quantified the expression of α-SMA as a marker of myofibroblasts in the invasive breast cancer. After staining samples for α-SMA, their expression was extracted and quantified as a relative percentage by computer-assisted image analysis.


RESULTS
There was relatively wide variation in the expression of α-SMA with the percentage of the area from 0.68 to 28.15% (mean 8.48 ± 5.40%). The metastasis group showed significantly higher α-SMA expression compared with the no metastasis group (p < 0.001). When the patients were divided into two groups according to their α-SMA expression using a cutoff point at the mean value of 8.48%, the high α-SMA group had a significantly poorer overall survival rate (p < 0.001). Multivariate analysis demonstrated that α-SMA and lymph node metastasis were identified as independent predictive factors of metastasis.


CONCLUSIONS
Myofibroblasts represent an important prognostic factor for invasive growth that is translated into a poor clinical prognosis for patients with invasive breast cancer.
Department of Breast Surgery, Mie University Graduate School of Medicine, Tsu, Japan. maa920@clin.medic.mie-u.ac.jp
Masako
M
Yamashita
Tomoko
T
Ogawa
Xinhui
X
Zhang
Noriko
N
Hanamura
Yumi
Y
Kashikura
Mitsuyuki
M
Takamura
Misao
M
Yoneda
Taizo
T
Shiraishi
D000199:Actins / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism / Q000401:mortality* / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000401:mortality / Q000556:secondary; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D058628:Myofibroblasts / Q000378:metabolism / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000401:mortality / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D017154:Stromal Cells / Q000378:metabolism / Q000473:pathology*; D015996:Survival Rate
D000199:Actins; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases