Human kallikrein 10 ELISA development and validation in breast cancer sera.
BACKGROUND
Human kallikrein 10 (hK10) is a putative secreted serine protease belonging to the same gene family as prostate specific antigen (hK3; PSA). There is significant interest in measuring hK10 which may act as a tumor suppressor in some cancers. We have developed an ELISA for hK10 and determined its analytical and clinical performance in normal and breast cancer sera.


METHODS
The assay used a previously described pair of monoclonal anti-hK10 antibodies and recombinant hK10 protein. Serum hK10 was detected quantitatively in a 2-step sandwich ELISA with colorimetric detection. The assay was analytically validated and used to determine serum levels of hK10 in a set of breast cancer, benign breast disease and normal samples.


RESULTS
The assay covered a linear range of 0.2 to 15 ng/mL and had a detection limit of 0.08 ng/mL. The within-run and between-run imprecision was <9%. The average spike and dilution linearity recoveries were 96 and 103% respectively. Mean hK10 concentration in normal female sera was 0.79+/-0.26 ng/mL. Concentrations were not age related and were not significantly different from benign fibrocystic disease or breast cancer. However, in a subset of breast cancer patients with both early and late stage disease, serum hK10 levels were elevated, at >1.55 ng/mL, above all normal female and benign disease samples.


CONCLUSIONS
We report in detail the analytical performance of a colorimetric hK10 ELISA validated in human serum and report for the first time the hK10 serum concentration in benign and breast cancer samples.
Ewan King
Lindsay
L
IBEX Pharmaceuticals, 5485 Pare, Montreal, Quebec, Canada. lking@ibex.ca
Li
Xiaogang
X
Cheikh Saad Bouh
Kane
K
Pedneault
Marc
M
Chu
Chee-Wui
CW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007610:Kallikreins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
C100936:KLK10 protein, human; D007610:Kallikreins