KLK6 and KLK7 mRNA and protein levels significantly increase in tissue and serum samples from early stage serous carcinomas. (A) Gene expression of KLK6 (solid black bar) and KLK7 (solid gray bar) in serous and papillary serous carcinomas from each tumor stage (I, II, III, and IV) was analyzed by qRT-PCR, and the mean fold changes were calculated by normalizing against expression in normal epithelial ovary tissues (N). The number of samples used in the analyses is denoted in parentheses, and standard error bars are indicated. (B) Specific protein expression analyzed in immune-blots of pooled normal (N) donor sera (n = 11) and various subtypes (serous and papillary serous only is indicated by an asterisk) from OVC patients of multiple stages (I, II, III, and IV). All serum samples were pre-cleared to deplete the 12 most abundant serum proteins prior to electrophoresis (SDS-PAGE). KLK protein expression in each sample was normalized relative to the internal transferrin signal. The histograms in the graphs adjacent to the immune-blots display the fold changes in KLK protein expression levels, normalized against pooled normal (N) serum and transferrin, as measured by quantitative densitometry.