Background: The correlation between ELISA level and immunohistochemical status for thymidine phosphorylase (TP) in invasive breast carcinoma was examined.
Materials and methods: Specimens were obtained from 84 patients with invasive breast carcinoma and both the ELISA level and immunohistochemical status for TP of breast carcinoma tissue were determined. The results of ELISA for the 84 cases were categorized into quartiles (E-scores 1 to 4) with every category including an equal number of patients. In addition, both the staining intensity of carcinoma cells and relative number of stained stromal cells identified by immunohistochemistry were classified into 4 degrees (I-scores 1 to 4). We also divided the patients into two groups: a negative group (I-scores 1 and 2) and a positive group (I-scores 3 and 4). Furthermore, sums of scores for carcinoma cells and stromal cells (S-scores 2 to 8) were divided into two groups, a low group (S-scores 2 to 5) and a high group (S-scores 6 to 8). The correlation between the ELISA level and immunohistochemical status for TP was evaluated and the means of the ELISA level of each group were compared.
Results: Scores of ELISA (E-scores) were significantly positively-correlated with scores for immunohistochemical status (I-scores) of only carcinoma cells (lambda=0.158, p<0.05). The means of TP levels determined by ELISA were significantly higher in the carcinoma cell-positive group (p<0.01) and summed-score high group (p<0.0002).
Conclusion: A positive correlation between the results of the ELISA and immunohistochemical status for TP was found only for carcinoma cells and comparison of means of the ELISA level indicated that they reflected total immunohistochemical TP status of carcinoma cells and stromal cells. Immunohistochemical examinations should be performed to clarify the in situ localization of TP in carcinoma tissue and the results obtained from the immunohistochemistry, as well as the ELISA of TP, may be useful in selection of patients for doxifluridine and capecitabine therapy.