Immunohistochemistry quantification by a digital computer-assisted method compared to semiquantitative analysis.
OBJECTIVE
To compare immunostaining quantification obtained by a digital computer-assisted method with the well-established semiquantitative analysis.


METHODS
Cytoplasmic staining of galectin-3 was obtained by standard immunohistochemical reactions in 25 cases of well-differentiated thyroid carcinoma. The expression index that associates the conventional area fraction of labeled cells with the immunostaining intensity score based on visual qualitative observation was used as the semiquantitative analysis. A digital computer-assisted method is described based on the use of an image processing program (ImageLab). Three parameters were obtained: (1) percentage of labeled cells; (2) digital immunostaining intensity, and (3) digital expression index. The proposed method allows numerical analysis of the immunostaining intensity.


RESULTS
There was a strong correlation between the immunostaining intensity obtained by the two methods (Pearson correlation coefficient, r = 0.71, P = 0.0001). The same was observed between expression indexes (Pearson correlation coefficient, r = 0.66, P = 0.0001).


CONCLUSIONS
Results obtained with our proposed digital computer-assisted method for immunoexpression analysis were concordant with the semiquantitative analysis. In addition, digital values can also resolve disagreement among different observers about the quality of staining intensity because the digital method does not classify the results into groups, but rather provides a numerical value for each individual case; thus, it increases the diagnostic and, more importantly, the prognostic sensitivity of the immunohistochemical analysis.
Matos
Leandro Luongo de
LL
Biochemistry Department, Molecular Biology Laboratory, Faculty of Medicine, ABC Foundation, São Paulo, SP, Brazil. lmatos@amcham.com.br
Stabenow
Elaine
E
Tavares
Marcos Roberto
MR
Ferraz
Alberto Rosseti
AR
Capelozzi
Vera Luiza
VL
Pinhal
Maria Aparecida da Silva
MA
D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000175:diagnosis / Q000648:ultrastructure; D002454:Cell Differentiation; D037502:Galectin 3 / Q000032:analysis; D006801:Humans; D019044:Image Cytometry / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007150:Immunohistochemistry / Q000379:methods*; D013194:Staining and Labeling / Q000706:statistics & numerical data*; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000648:ultrastructure
D014408:Biomarkers, Tumor; D037502:Galectin 3