Estrogen receptors in 699 primary breast cancers: a comparison of immunohistochemical and biochemical methods.
BACKGROUND
Over the last few years, estrogen receptor (ER) determination by immunohistochemistry (ER-ICA) has been extensively used, but it still remains to be established whether this method can replace the standard biochemical technique using dextran-coated charcoal (ERDCC).


METHODS
ER were determined by both the dextran-coated charcoal (DCC) method and immunohistochemistry (ICA) in 699 patients with primary breast cancer; other parameters (age, pathological T-pT- and nodal status -pN-, progesterone receptors by DCC, proliferative index by ICA) were also recorded. The 'best' cut-off for ERICA was evaluated by means of Receiver Operating Characteristics (R.O.C.) analysis; logistic regression analysis was used to find adequate 'weights' for stain intensity.


CONCLUSIONS
A significant correlation was found between the two methods (p < 0.001). R.O.C. analysis revealed that the 'best' cut-off for the ERICA score was 45% (sensitivity 0.810, specificity 0.804). Logistic regression analysis showed that an ERICA score which also considers staining intensity does not add any useful information concerning ER content in breast cancers.
Molino
A
A
Department of Medical Oncology, University of Verona, Italy.
Micciolo
R
R
Turazza
M
M
Bonetti
F
F
Piubello
Q
Q
Corgnati
A
A
Sperotto
L
L
Martignoni
G
G
Bonetti
A
A
Nortilli
R
R
D001943:Breast Neoplasms / Q000648:ultrastructure*; D002606:Charcoal; D003911:Dextrans; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D012372:ROC Curve; D011960:Receptors, Estrogen / Q000032:analysis*; D013194:Staining and Labeling / Q000379:methods
D003911:Dextrans; D011960:Receptors, Estrogen; D002606:Charcoal