Cyclin I mRNA expression correlates with kinase insert domain receptor expression in human epithelial ovarian cancer

Ovarian cancer is the second most common gynecological malignancy after cancer of the uterine corpus, and the fifth leading cause of cancer-related death among women. It has been discovered that cyclin I (CCNI) protein expression correlates with the proliferation of cancer cells and expression of angiogenesis-related proteins, such as vascular endothelial growth factor (VEGF) and VEGF receptor 2/kinase insert domain receptor (VEGFR2/KDR). We examined whether any association exists between mRNA expression of CCNI and KDR genes in epithelial ovarian cancer (EOC) tissues, clinicopathological parameters and patients' response to chemotherapy.

Expression of CCNI and KDR genes was analyzed by quantitative real-time reverse transcription PCR in 40 human primary EOC tissues and four human ovarian cancer cell lines (TOV-112D, OV-90, OVCAR-3 and Caov-3).

CCNI and KDR mRNA expression was detected in all EOC tissues and ovarian cancer cell lines. The mRNA levels of both genes were significantly higher in EOC than in ovarian cancer cell lines (p<0.001). Neither CCNI nor KDR mRNA expression in EOC tissues was significantly associated with variables such as age, menopausal status, International Federation of Gynecology and Obstetrics (FIGO) stage, residual disease, patients' response to chemotherapy, tumor histology, grade or sensitivity to chemotherapy. However, we demonstrated a significant positive correlation between the mRNA expression of KDR and CCNI in EOC tissues (R=0.530, p<0.001).

Neither CCNI nor KDR mRNA expression predicts response of patients with EOC to platinum-based first-line chemotherapy. Cyclin I may be involved in angiogenesis in EOC, which needs further investigation.