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.
Garcia-Tuñón
I
I
Department of Cell Biology and Genetics, University of Alcalá and Department of Pathology, Hospital Principe de Asturias, Alcalá de Henares, Madrid, Spain.
Ricote
M
M
Ruiz
A
A
Fraile
B
B
Paniagua
R
R
Royuela
M
M
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