Expression of drug resistance protein related to Tc-99m MIBI breast imaging

Adjuvant and neoadjuvant chemotherapy is increasingly being used in the tre atment of breast cancer patients. However drug resistance plays an importan t role in chemotherapy failure in this cancer. The aim of this study was to determine the correlation between technetium-99m sestamibi (Tc-99m MIBI) b reast imaging results and expression of the drug resistance proteins (p-gly coprotein (Pgp), Ki-67 and mutant p53) in human breast cancer tissues. Twen ty-four breast cancer patients underwent Tc-99m MIBI breast imaging before surgery or biopsy. Protein expression was investigated by immunohistochemic al studies on multiple nonconsecutive sections of surgery or biopsy samples . Tumor to background (TIB) ratios calculated by Tc-99m MIBI breast imaging were correlated with protein expression determined by immunohistochemical studies The TIE ratios were significantly lower in 8 patients with positive Pgp expression (Group I) when compared with 16 patients with negative Pgp expression (Group 2) (1.40 +/- 0.11 and 276 a 0.60 p < 0.05). However, the differences of TIE ratios between the patients with positive and negative K i-67 mutant p53 expression were not significant. Our data confirmed that Tc -99m MIBI breast imaging is useful for determination of the presence of Pgp expression in breast cancer patients No significant relationship between T c-99m MIBI breast imaging results and Ki67/mutant p53 was found.