Technetium-99m-Sestamibi Uptake By Breast Carcinoma: Correlation With P-Glycoprotein, Multidrug Resistance-associated Protein And Glutathione S Transferase-pi

Purpose: We prospectively studied a total of 30 patients with breast carcinoma,to evaluate the relationship between the accumulation of (99m)~Tc-sestamibi andp-glycoprotein (Pgp), multidrug resistance-associated protein (MRP) andglutathione S transferase –pi (GST-π) expression in tumor tissues.Methods: Thirty patients underwent early and delayed (99m)~Tc-sestamibiscintigraphy. Pathological status and immunohistochemical studies were performedon multiple nonconsecutive sections of the same tumor using a MRP-specificmonoclonal antibody, QCRL-2, and a Pgp-specific monoclonal antibody, C-219and a GST-πspecific monoclonal antibody, 353-10.Early and delayedtumor-to-normal (T/N) ratios, retention index were correlated with the levels ofMRP, Pgp and GST-πexpression determined by immunohistochemical studies.Results: The T/N (d) ratios were lower for those with MRP and Pgp expression thanthose with no expression(P<0.05), and there was no statistically significantdifference in T/N (d)ratios between GST-πexpression group and no expressiongroup (P=0.48). There were no statistically significant differences in T/N (e) ratiosbetween all groups of MRP, Pgp and GST-π. There was statistically significantdifference in RI between those with MRP expression and those with no expression(p=0.001), and no statistically significant difference in RI between those with Pgpor GST-πexpression and with no expression (p>0.05 ). There were no correlationbetween Pgp ,MRP and GST-π.Conclusion: (99m)~ Tc-MIBI scintimammography is useful in the determination of thepresence of MRP and Pgp in patients with breast carcinoma.