Comparison of the expression of P-glycoprotein, Ki-67, and P-53 to technetium-99m tetrofosmin mammoscintigraphic findings.

Adjuvant and neoadjuvant chemotherapy is being used increasingly in the treatment of breast cancer patients. However, drug resistance plays an important role in the failure of chemotherapy in breast cancer. The aim of this study was to compare technetium-99m tetrofosmin (Tc-TETRO) mammoscintigraphic findings with the expression of drug resistance proteins (p-glycoprotein [Pgp], Ki-67 and mutant p53) in human breast cancer tissues. Thirty patients diagnosed with infiltrating ductal breast cancer underwent Tc-TETRO mammoscintigraphy before surgery or biopsy. Protein expression was investigated by immunohistochemical analyses on multiple nonconsecutive sections from surgery or biopsy specimens. Tumor to background (T/B) ratios calculated by Tc-TETRO mammoscintigraphic findings were correlated with protein expression determined by immunohistochemical analyses. The Tc-TETRO T/B ratios were significantly lower for tumors in 12 patients with positive Pgp expression than for those in 18 patients with negative expression (1.19 +/- 0.13 and 1.94 +/- 0.33, p value < 0.01). However, differences in Tc-TETRO T/B ratios between the patients with positive and negative Ki-67 or mutant p53 expression were not found in this study. Our data confirmed that Tc-TETRO mammoscintigraphic findings are useful for determination of the presence of Pgp expression in breast cancer patients, but no significant relations between Tc-TETRO mammoscintigraphic findings and Ki67 or mutant p53 were found.