Expression of metastases-associated genes in cervical cancers resected in the proliferative and secretory phases of the menstrual cycle.
Academic Article
Overview
abstract
Previous retrospective studies suggest that the phase of the menstrual cycle at surgery (proliferative versus secretory) for breast cancer may significantly affect patient survival. Fluctuations during the menstrual cycle of the expression of genes involved in metastases in breast cancer tissue have also been reported. We hypothesized that the menstrual phase may also affect similar changes in gene expression of other cancers. We focused our attention on cancer of the uterine cervix because the hysterectomy specimen obtained at original surgery for the cancer can be used retrospectively to determine cycle phase. We analyzed tumor specimens from 36 premenopausal cervical cancer patients who had undergone hysterectomy as their primary treatment. We used reverse transcription-PCR to quantify gene expression during the different phases of the menstrual cycle as determined from the endometrial specimen. We explored a panel of genes that may affect metastatic propensity, namely, metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-2 (TIMP-2), cyclooxygenase 1 and 2 (COX-1 and COX-2), and vascular endothelial growth factor (VEGF). A significantly higher level of TIMP-2 and COX-2 gene expression (P = 0.007 and 0.030, respectively) was detected during the proliferative phase compared to the secretory phase of the cycle. The expression of the other genes was not significantly affected by the stage of the menstrual cycle. The finding that TIMP-2 and COX-2 expression in cervical cancer may be affected by the stage of the menstrual cycle supports the hypothesis that ovarian hormones may affect the expression of genes involved in metastasis. These findings need to be replicated, and their implications for tumor angiogenesis, invasion, and metastatic propensity need to be explored both in human studies and in experimental models.
