Down-regulation of hK7 in the sera of breast cancer and benign breast disease patients

INTRODUCTION: Breast cancer is known as a leading cause of cancer-related death among women all over the world. Biomarkers facilitate diagnosis at the earliest possible stage and better prognosis of the disease. Hence, may help to improve the overall survival rate among breast cancer patients. To find a better diagnostic/prognostic marker we evaluated human tissue kallikrein 7 (hK7) as biomarker of breast cancer. hK7 is a secreted serine protease having chymotrypsin like activity. Serum hK7 is known to have aberrant expression in ovarian and prostate cancer but has not been yet studied in breast cancer. However, the expression level of KLK7 mRNA in breast cancer tissues has been indicated as a better prognostic marker for the unfavorable prognosis of breast carcinoma. MATERIALS AND METHODS: In this study a time-resolved immunofluorometric indirect back titration ELISA (bt-ELISA) was employed for the quantification of hK7 in serum of breast cancer patients (n = 47), benign breast disease patients (n = 13) alongwith the gender and age group specific controls (n = 99). RESULTS: hK7 was significantly down-regulated in the sera of female breast cancer patients (p < 0.0001; Mean 0.704 ± 0.533 μg/L) and benign breast disease patients (p = 0.0008; Mean 0.651 ± 0.584) as compared to normal controls (Mean 1.665 ± 1.174 μg/L). CONCLUSIONS: Down regulation of hK7 suggests the possible role of this protein in natural course of breast cancer and benign breast diseases. Study should be extended on large-scale to confirm the potential of hK7 as biomarker of breast cancer.