Detection of Hsp27 in serum from breast cancer patients by immunoprecipitation/western blot technique

FANELLI M. A.; CUELLO CARRIÓN F. D.; CIOCCA D. R.

San Diego, CA, USA

Congreso; 88th Annual Meeting of the American Association for Cancer Research; 1997

American Association for Cancer Research.

Heat shock proteins (Hsps) are involved in cell protection mechanisms and they may be overexpressed in biopsy samples from breast cancer patients. Evidence for Hsps secretion and cell surface expression has been reported, in addition certain Hsps may act as specilic immunogenic determinants expressed in tumor cells. In the present study, we have examined whether the serum from normal and breast cancer patients contains detectable levels of Hsp27 or autoantibodies against this protein. We first analyzed 54 serum samples from healthy women (control group) and 20 serum samples from breast cancer patients (experimental group) to detect Hsp27 using Western blot technique. A specific/sharp Hsp27 protein band was not observed by Western blot in serum from normal and cancer patients. We next increased the sensitivity of the detection technique using immunoprecipitation with magnetic particles attached to a mouse monoclonal antibody against Hsp27; a second antibody (policlonal against a hybrid Hsp25/27 protein) was used for detecting the immunoprecipitate. In the control samples (11) we detected a band that when scanned gave 200 ± 106 O.D., while in the cancer samples (20) the band gave 374 ± 246 O.D. In breast cancer patients, the intensity levels of the Hsp27 bands did not correlate with the levels of the breast cancer antigen CA 15-3 (assayed by ELlSA). Finally, we studied the presence of autoantibodies against Hsp27 in 7 serum samples from breast cancer patients. Autoantibodies to Hsp27 were not detected using Westem blot technique. These results suggest that Hsp27 could be present in the serum of breast cancer patients at higher levels than in control healthy women.