Differential expression of cyclin E2 in cancers of the breast.
Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding cyclin E2, CCNE2, when comparing primary tumors of the breast to the tissue of origin, the normal breast. CCNE2 was also differentially expressed in the tumor cells of patients with triple negative breast cancer. CCNE2 mRNA was present at significantly higher quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of CCNE2 in primary tumors of the breast was correlated with distant metastasis-free survival in patients with luminal A subtype cancer. CCNE2 may be of relevance to initiation, maintenance or progression of cancers of the female breast.