Cyclin E and survival in patients with breast cancer.
BACKGROUND
Cyclin E, a regulator of the cell cycle, affects the behavior of breast-cancer cells. We investigated whether levels of cyclin E in the tumor correlated with survival among patients with breast cancer.


METHODS
Tumor tissue from 395 patients with breast cancer was assayed for cyclin E, cyclin D1, cyclin D3, and the HER-2/neu oncogene with the use of Western blot analysis. Full-length, low-molecular-weight, and total cyclin E were measured. Immunohistochemical assessments of cyclin E were also made of 256 tumors. We sought correlations between levels of these molecular markers and disease-specific and overall survival.


RESULTS
The median follow-up was 6.4 years. A high level of the low-molecular-weight isoforms of cyclin E, as detected by Western blotting, correlated strongly with disease-specific survival whether axillary lymph nodes were negative or positive for metastases (P<0.001). Among 114 patients with stage I breast cancer, none of the 102 patients with low levels of cyclin E in the tumor had died of breast cancer by five years after diagnosis, whereas all 12 patients with a high level of low-molecular-weight cyclin E had died of breast cancer within that period. In multivariate analysis, a high total cyclin E level or high levels of the low-molecular-weight forms of cyclin E were significantly correlated with poor outcome. The hazard ratio for death from breast cancer for patients with high total cyclin E levels as compared with those with low total cyclin E levels was 13.3--about eight times as high as the hazard ratios associated with other independent clinical and pathological risk factors.


CONCLUSIONS
Levels of total cyclin E and low-molecular-weight cyclin E in tumor tissue, as measured by Western blot assay, correlate strongly with survival in patients with breast cancer.
Keyomarsi
Khandan
K
Department of Experimental Radiation Oncology, University of Texas M.D. Anderson Cancer Center, Houston 77030-4095, USA. kkeyomar@mdanderson.org
Tucker
Susan L
SL
Buchholz
Thomas A
TA
Callister
Matthew
M
Ding
Ye
Y
Hortobagyi
Gabriel N
GN
Bedrosian
Isabelle
I
Knickerbocker
Christopher
C
Toyofuku
Wendy
W
Lowe
Michael
M
Herliczek
Thaddeus W
TW
Bacus
Sarah S
SS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000401:mortality* / Q000473:pathology*; D019938:Cyclin D1 / Q000032:analysis; D056743:Cyclin D3; D019927:Cyclin E / Q000032:analysis*; D016213:Cyclins / Q000032:analysis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D012189:Retrospective Studies; D016019:Survival Analysis
D019938:Cyclin D1; D056743:Cyclin D3; D019927:Cyclin E; D016213:Cyclins; D018719:Erb-b2 Receptor Tyrosine Kinases; C534696:CCND3 protein, human