Study On Relationship Of KLK5 And KLK7 MRNA Expression And Breast Cancer

BACKGROUND: KLK5 and KLK7 are among one of the members of thehuman kallikrein gene family. They have been found to be differentially expressed atthe mRNA level in many endocrine-related malignancies, and down-regulated inbreast cancer. They were up-regulated in breast cancer cells by both estrogens andglucocorticoids. Recent evidences indicate that the expression of KLK5 and KLK7are associated with prognosis of breast cancer. This study was to investigate thecorrelation between KLK5 and KLK7; the mRNA expression level of KLK5 andKLK7 in normal breast tissues, benign breast tissues, breast cancer tissues andmetastatic lymph node tissues; and the clinicopathologic significance of KLK5 andKLK7mRNA expression in breast cancer tissues.METHODS: Real-time RT-PCR was used to quantify KLK5 and KLK7mRNA expression level of 30 cases normal breast tissues, 30 cases benign tissues,107 cases primary breast cancer specimens and 30 cases lymph node metastasesspecimens. The correlation between KLK5 and KLK7 mRNA expression and severalclinicopathologic parameters, including clinical stage, pathologic tumor size, axillarylymph node status, estrogen receptor status, local relapse and distant metastasis wereanalyzed using SPSS software package.RESULTS: The mRNA level of KLK5 and KLK7 were both significantlydown-regulated in breast cancer tissues than normal breast tissues and benign breasttissues. There were no significant differences of KLK5 and KLK7 mRNAexpression between primary cancer tissues and metastatic lymph node tissues. KLK5gene expression was significantly higher in breast cancer patients with negtiveprogesterone receptors. KLK7 gene expression was significantly higher in breastcancer patients with 4 to 9 positive lymph nodes than other groups. No significant differences were found between the mRNA level of KLK5 and KLK7 and otherclinicopathological characteristics. Furthermore, breast cancer patients with themiddle mRNA expression of KLK5 have statistically longer disease-free survival(DFS) than patients with the low and hign mRNA expression of KLK5; and breastcancer patients with the middle mRNA expression of KLK7 also have a sametendency, but the difference shows no significance. The correlation between themRNA level KLK5 and KLK7 in breast cancer patients is 0.83, the difference showssignificance.CONCLUSIONS: These data suggest that KLK5 and KLK7gene expressionwere hopeful to be the molecular marker used for diagnosis of breast cancer, theymay be used as the marker of prognosis for breast cancer patients. Except benignbreast tissues, KLK5 and KLK7 are likely cooperated to express in breast tissues.