IL-6, its receptors and its relationship with bcl-2 and bax proteins in infiltrating and in situ human breast carcinoma.
OBJECTIVE
To characterize the expression pattern of IL-6 and its receptors (IL-6R(alpha) and gp130), to relate this pattern to bcl-2 and bax expression and to elucidate the effects on the proliferation/apoptosis equilibrium in benign conditions and in situ and infiltrating breast cancer.


RESULTS
The immunoexpression of IL-6 and its receptors (IL-6R(alpha) and gp130), and their relationship with bcl-2 and bax proteins, were studied in in situ and infiltrating tumours and in benign breast lesions by means of Western blotting and immunohistochemistry. The percentages of samples positive for IL-6, bcl-2 and bax and their immunoreaction densities were higher in in situ carcinomas and infiltrating tumours than in benign lesions; although in in situ lesions were not so high as in infiltrating tumours, except for bax, whose immunoexpression was as weak as in benign conditions, resulting in a bcl-2/bax ratio higher than in infiltrating tumours.


CONCLUSIONS
The high expression of IL-6 and its receptors in tumours might be related to the enhanced cell proliferation occurring in breast cancer. IL-6 could act by increasing bcl-2 expression and thus altering the proliferation/apoptosis balance toward neoplastic cell proliferation. The increased bax immunoreactivity observed only in infiltrating tumours, which was not so high as the increase in bcl-2 immunoreactivity, might be interpreted as an attempt to hinder cell proliferation.
Department of Cell Biology and Genetics, University of Alcalá and Department of Pathology, Hospital Principe de Asturias, Alcalá de Henares, Madrid, Spain.
I
I
Garcia-Tuñón
M
M
Ricote
A
A
Ruiz
B
B
Fraile
R
R
Paniagua
M
M
Royuela
D000293:Adolescent; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology*; D002278:Carcinoma in Situ / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology*; D050822:Cytokine Receptor gp130; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000032:analysis; D008562:Membrane Glycoproteins / Q000032:analysis; D008875:Middle Aged; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D019947:Receptors, Interleukin-6 / Q000032:analysis; D051028:bcl-2-Associated X Protein
D015703:Antigens, CD; C494826:BAX protein, human; D014408:Biomarkers, Tumor; C494199:IL6ST protein, human; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D019253:Proto-Oncogene Proteins c-bcl-2; D019947:Receptors, Interleukin-6; D051028:bcl-2-Associated X Protein; D050822:Cytokine Receptor gp130