Activation of stat3 in primary tumors from high-risk breast cancer patients is associated with elevated levels of activated SRC and survivin expression.
OBJECTIVE
Constitutive activation of signal transducer and activator of transcription 3 (Stat3) protein has been observed in a wide variety of tumors, including breast cancer, and contributes to oncogenesis at least in part by prevention of apoptosis. In a study of 45 patients with high-risk breast cancer enrolled in a phase II neoadjuvant chemotherapy trial with docetaxel and doxorubicin, we evaluated the levels of Stat3 activation and potentially associated molecular biomarkers in invasive breast carcinoma compared with matched nonneoplastic tissues.


METHODS
Using immunohistochemistry and image analysis, we quantified the levels of phospho-Stat3 (pY-Stat3), phospho-Src (pY-Src), epidermal growth factor receptor, HER2/neu, Ki-67, estrogen receptor, Bcl-2, Bcl-xL, Survivin, and apoptosis in formalin-fixed, paraffin-embedded sections from invasive carcinomas and their paired nonneoplastic parenchyma. The levels of molecular biomarkers in nonneoplastic and tumor tissues were analyzed as continuous variables for statistically significant correlations.


RESULTS
Levels of activated pY-Stat3 and pY-Src measured by immunohistochemistry were significantly higher in invasive carcinoma than in nonneoplastic tissue (P < 0.001). In tumors, elevated levels of pY-Stat3 correlated with those of pY-Src and Survivin. Levels of pY-Stat3 were higher in partial pathologic responders than in complete pathologic responders. In partial pathologic responders, pY-Stat3 levels correlated with Survivin expression.


CONCLUSIONS
Our findings suggest important roles for elevated activities of Stat3 and Src, as well as Survivin expression, in malignant progression of breast cancer. Furthermore, elevated Stat3 activity correlates inversely with complete pathologic response. These findings suggest that specific Stat3 or Src inhibitors could offer clinical benefits to patients with breast cancer.
Diaz
Nills
N
Pathology, H. Lee Moffitt Cancer Center and Research Institute, Department of Interdisciplinary Oncology, University of South Florida College of Medicine, Tampa, Florida, USA.
Minton
Susan
S
Cox
Charles
C
Bowman
Tammy
T
Gritsko
Tanya
T
Garcia
Roy
R
Eweis
Ibrahim
I
Wloch
Marek
M
Livingston
Sandy
S
Seijo
Ed
E
Cantor
Alan
A
Lee
Ji-Hyun
JH
Beam
Craig A
CA
Sullivan
Daniel
D
Jove
Richard
R
Muro-Cacho
Carlos A
CA
D000970:Antineoplastic Agents / Q000627:therapeutic use; D017209:Apoptosis / Q000502:physiology; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D017322:Clinical Trials, Phase II as Topic; D000077143:Docetaxel; D004317:Doxorubicin / Q000627:therapeutic use; D024202:Electrophoretic Mobility Shift Assay; D004789:Enzyme Activation / Q000502:physiology; D066246:ErbB Receptors / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D051034:Inhibitor of Apoptosis Proteins; D019394:Ki-67 Antigen / Q000096:biosynthesis; D008869:Microtubule-Associated Proteins / Q000096:biosynthesis*; D020360:Neoadjuvant Therapy; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis; D011960:Receptors, Estrogen / Q000096:biosynthesis; D012307:Risk Factors; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D000077022:Survivin; D043823:Taxoids / Q000627:therapeutic use; D051020:bcl-X Protein / Q000096:biosynthesis; D019061:src-Family Kinases / Q000096:biosynthesis*
D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D000077143:Docetaxel; D004317:Doxorubicin; D066246:ErbB Receptors; D051034:Inhibitor of Apoptosis Proteins; D019394:Ki-67 Antigen; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D050796:STAT3 Transcription Factor; D000077022:Survivin; D043823:Taxoids; D051020:bcl-X Protein; D019061:src-Family Kinases; C494811:BCL2L1 protein, human; C107489:BIRC5 protein, human; C494086:STAT3 protein, human