COMPARISON BETWEEN WESTERN BLOTTING, IMMUNOHISTOCHEMICAL AND ELISA ASSAY FOR P185(NEU) QUANTITATION IN BREAST-CANCER SPECIMENS

The protein encoded by erbB2 oncogene was evaluated by three different methological approaches (Western blotting, ELISA and immunohistochemi stry) in 147 breast cancer specimens. A highly significant correlation was found between Western blotting and ELISA results (p<0.001). The d ata from ELISA and Western blotting were categorized as negatives (-), low-overexpressing (+) and high-overexpressing (++). Immunohistochemi cal results were classified as (-) or (+) according to the absence or the presence of specific staining. Overall positive cases (+ and ++) w ere 42.2% by Western blotting and 51% by ELISA, while (++) cases were 23.8% and 25.2% respectively. Histochemical staining was found in 29.8 % of cases. The two by two evaluation of the assays showed a close ass ociation (chi(2), p < 0.0001). In particular, the comparison between b oth ELISA and Western blotting with immunohistochemistry showed concor dance rates of 78.9% for ELISA and 83.1% for Western blotting consider ing the + and + + cases as a single group. When only the ++ cases were considered as positive, the overall agreement rises to 93.3% and 89.1 % respectively. From these preliminary data we conclude that p185 valu es obtained with the three evaluated methods are possibly superimposab le. Nevertheless, the biochemical methods seem to identify an intermed iate p185 expression group, whose clinical meaning should be investiga ted