Ch. Kao et al., P-glycoprotein and multidrug resistance-related protein expressions in relation to technetium-99m methoxyisobutylisonitrile scintimammography findings, CANCER RES, 61(4), 2001, pp. 1412-1414
The purpose of this study was to retrospectively study 48 patients with inf
iltrating ductal breast cancer to evaluate the relationship between the deg
ree of accumulation of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) a
nd P-glycoprotein (Pgp) or multidrug resistance-related protein (MRP) expre
ssion in breast cancer tissues. Before surgery or biopsy, all 48 patients u
nderwent scintimammography started 10 min after the injection of Tc-MIBI. T
umor:background (T:B) ratios were calculated from the Tc-MIBI scintimammogr
aphy, Immunohistochemical analysis was performed on the pathological specim
ens of the 48 breast tumors to determine Pgp and MRP expression. According
to the results of immunohis tochemical analysis, the 48 breast cancers were
separated into four groups: (a) group 1, 12 cancers with both positive Pgp
expression and positive MRP expression; (b) group 2, 12 cancers with posit
ive Pgp expression and negative MRP expression; (c) group 3, 12 cancers wit
h negative Pgp expression and positive MRP expression; and (6) group 4, 12
cancers with both negative Pgp expression and negative MRP expression. Amon
g the four groups, the T:B ratio was lowest in group 1 (1.13 +/- 0.10) and
highest in group 4 (2.17 +/- 0,14), respectively (P < 0,05), The T:B ratios
of groups 2 (1.30 +/- 0.25) and 3 (1.32 +/- 0.26) were between those of gr
oups 1 and 4, Our data confirmed that Tc-MIBI scintimammography is useful f
or determining Pgp and MRP expression in patients with breast cancers.