Osteopontin Fragments with Intact Thrombin-Sensitive Site Circulate in Cervical Cancer PatientsReport as inadecuate

Osteopontin Fragments with Intact Thrombin-Sensitive Site Circulate in Cervical Cancer Patients - Download this document for free, or read online. Document in PDF available to download.

We investigated whether circulating osteopontin OPN could be used as a biomarker for cervical cancer. We employed a monoclonal antibody mAb 659 specific for the unique and intact thrombin-sensitive site in OPN using an inhibition ELISA. We found significantly higher levels of OPN in 33 cervical cancer patients in both the plasma mean +- SD, 612 +- 106 ng-mL and serum 424 +- 121 ng-mL compared to healthy subjects 409 +- 56 ng-mL, from 31 plasma samples P < 0.0001, and 314 +- 98 ng-mL, from 32 serum samples P = 0.0002, respectively. Similar results were obtained when the plasma from a bigger group 147 individuals of cervical cancer patients 560 +- 211 ng-mL were compared with the same plasma samples of the healthy individuals P = 0.0014. More significantly, the OPN level was highest in stage III-IV disease 614 +- 210 ng-mL, from 52 individuals; P = 0.0001 and least and non-discriminatory in stage I 473 +- 110 ng-mL, from 40 individuals; P = 0.5318. No such discrimination was found when a mAb of a different specificity mAb 446 was used in a similar inhibition ELISA to compare the two groups in the first study; a commercial capture ELISA also failed. The possibility that the target epitope recognized by the antibody probe in these assays was absent from the circulating OPN due to protein truncation was supported by gel fractionation of the OPN found in patients’ plasma: 60–64 kDa fragments were found instead of the presumably full-length OPN 68 kDa seen in healthy people. How these fragments are generated and what possible role they play in cancer biology remain interesting questions.

Author: Danny T. M. Leung, Pak-Leong Lim , Tak-Hong Cheung, Raymond R. Y. Wong, So-Fan Yim, Margaret H. L. Ng, Frankie C. H. Tam, Tony K.

Source: http://plos.srce.hr/


Related documents