p95HER-2 predicts worse outcome in patients with HER-2-positive breast cancer.
BACKGROUND
The HER-2 receptor undergoes a proteolytic cleavage generating an NH(2)-terminally truncated fragment, p95HER-2, that is membrane-associated and tyrosine-phosphorylated. We have reported that p95HER-2, but not the full-length receptor, p185HER-2, correlated with the extent of lymph node involvement in patients with breast cancer and its expression was significantly enhanced in nodal metastatic tissue. These facts suggested an important role for p95HER-2 either as a marker or cause of metastasis and poor outcome in breast cancer. In this work, we have studied the prognostic value of p95HER-2 in breast cancer.


METHODS
Primary breast tumor tissues (n = 483) were from surgical resections conducted in hospitals in two different countries: the U.S. (n = 334) and Spain (n = 149). HER-2 protein forms, including p185HER-2 and p95HER-2, were examined in extracts of primary breast tumors by Western blot analysis. The levels of the two forms (high or low) were tested for association with other clinicopathologic factors and for correlation with disease-free survival.


RESULTS
The median follow-up was 46 months. A high level of p95HER-2 in primary tumor tissue correlated with reduced 5-year disease-free survival (hazard ratio, 2.55; 95% confidence interval, 2.13-8.01; P < 0.0001). The median time for disease-free survival was 32 versus 139 months in patients with low levels of p95HER-2. In comparison, high levels of the full-length p185HER-2 did not significantly correlate with poor outcome (P > 0.1). Multivariate analysis revealed that high p95HER-2 was an independent predictor of disease-free survival (hazard ratio, 1.59; 95% confidence interval, 1.246-1.990; P = 0.0004).


CONCLUSIONS
p95HER-2 expression is an independent prognostic factor in breast cancer and defines a group of patients with HER-2-positive breast cancer with significantly worse outcome.
Sáez
Rosana
R
Cell Biology Department, Faculty of Biological Sciences, University of Valencia, Burjasot, Valencia, Spain.
Molina
Miguel A
MA
Ramsey
Elizabeth E
EE
Rojo
Federico
F
Keenan
Edward J
EJ
Albanell
Joan
J
Lluch
Ana
A
García-Conde
Javier
J
Baselga
José
J
Clinton
Gail M
GM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism* / Q000473:pathology; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012307:Risk Factors; D015996:Survival Rate; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone