Usefulness of Technetium-99m-Tetrofosmin Mammoscintigraphy to Predict Expressions of P-Glycoprotein and Multidrug Resistance Related Protein: A Preliminary Report

Received 4/4/2002; revised 4/16/2002; accepted 4/23/2002. For correspondence or reprints contact: Chia-Hung Kao, M.D., Department of Nuclear Medicine, China Medical College Hospital, 2 Yuh-Der Road, Taichung 404, Taiwan. Tel: (886)4-22052121 ext. 3475, Fax: (886)4-22023442, E-mail: [email protected] Purpose: The aim of this study was to evaluate the relationship between the tumor uptake of technetium99m-tetrofosmin (Tc-TF) and the expressions of Pglycoprotein (Pgp) and multidrug resistance related protein (MRP) in breast cancers. Methods: Determination of Pgp and MRP expressions were performed by immunohistochemical analyses (IHA) on biopsy or surgery specimens of the 20 breast cancers. According to the results of IHA, the 20 breast cancers were separated into 2 groups: (A) 10 tumors with positive MRP and Pgp expressions, and (B) 10 tumors with negative MRP and Pgp expressions. All of the 20 patients underwent Tc-TF mammoscintigraphy to calculate tumor to background (T/B) ratios on breast cancers before IHA and biopsy/surgery. Results: Between the 2 groups, the T/B ratios were significantly lower in group A (1.15 ± 0.10) than in group B (2.19 ± 0.15) (P < 0.001). Conclusion: Our results indicate that Tc-TF mammoscintigraphy is helpful for predicting of Pgp and MRP expressions in breast cancers.