FOXP3 expression is related to high Ki-67 index and poor prognosis in lymph node-positive breast cancer patients.
BACKGROUND
Recent preclinical studies have shown that Forkhead box protein 3 (FOXP3) is an important tumor suppressor gene. The clinical and prognostic implication of FOXP3 expression in breast cancer cells still remains controversial.


METHODS
We evaluated the FOXP3 expression status of 183 patients who underwent curative surgery for breast cancer using the immunohistochemical assay of tissue microarray.


RESULTS
We found FOXP3 expression in 51 out of 183 (27.9%) surgically resected breast cancer tumors, and 33 patients were scored as weak positive and 18 as strong positive. FOXP3-positive tumors were associated with significantly higher nuclear grade, higher histologic grade and a more negative estrogen receptor status. The FOXP3 expression level was independently associated with high Ki-67 index in a logistic regression model. In the node-positive subgroup, strong FOXP3 positivity was related to poor disease-free survival and disease-specific survival compared to FOXP3-negative patients, whereas there was no survival difference between FOXP3-negative and FOXP3-weak-positive patients. Multivariate analysis with adjustment for patient age and human epidermal growth factor receptor 2 status demonstrated significantly poor survival of FOXP3-strong-positive patients in node-positive patients.


CONCLUSIONS
Our results suggest that strong FOXP3 expression in breast cancer cells is associated with poor prognosis and high Ki-67 index.
Division of Medical Oncology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
Min Hwan
MH
Kim
Ja Seung
JS
Koo
Soohyeon
S
Lee
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000401:mortality / Q000556:secondary / Q000628:therapy; D049109:Cell Proliferation; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006801:Humans; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000378:metabolism*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D016896:Treatment Outcome
C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D019394:Ki-67 Antigen