The mRNA levels of KLK5 and KLK7 were both downregulated in breast cancers relative to normal and benign tissues, and downregulated in metastases compared to primary cancers.
The steroid hormone receptor-positive breast cancer cell line BT-474 was used to examine the effect of different steroids on the expression levels of KLK5-SV2.
X-profiler comparison of two pools of normal and breast cancer libraries further verified the presence of significant downregulation of expression levels of 4 of the kallikreins genes (KLK5, 6, 10, 12).
Like the genes that encode PSA and other kallikreins, the KLK5 gene was found to be regulated by steroid hormones in the BT-474 breast cancer cell line.