Is early sestamibi imaging in head and neck cancer affected by MDR status, p53 expression, or cell proliferation?
A consensus has emerged that early imaging (within 20 min post-injection [p.i.] of sestamibi) has the highest diagnostic yield. Tc-99m-sestamibi uptake has been associated with P-glycoprotein-mediated multi-drug resistance (MDR), tumor vascularization, invasiveness, and cell proliferation. The aim of this study was to assess whether these parameters affect tumor uptake in current imaging protocols. Twenty-three patients with squamous cell carcinoma (SCC) of the mouth floor who were scheduled for surgery were imaged 5 min. p.i. with a triple-head gamma camera (360 degrees, 3 degrees/step SPECT, UHRPAR collimators). Tumor:nontumor tissue (TBR), tumor:gingiva (TGR), tumor:salivary gland (TSR), and tumor:nuchal muscle ratios (TNR) were calculated based on the cts/pix values of ROIs in the axial slices. The expression of the MDR gene was determined histochemically from biopsies. Cell proliferation was quantitated by the histochemical analysis of the Ki-67 protein (Ki-67 index); additionally, the p53 tumor suppressor gene (p53 index), a posttranslational stabilizer of the cell cycle at the G1 stage, was assessed. No significant differences were found for the uptake indices between MDR+ and MDR- tumors. Moreover, no significant correlation between sestamibi uptake and the Ki-67 and p53 indices could be demonstrated. The diagnostic information content of currently applied imaging protocols for sestamibi in SCC of the mouth floor is not affected by tumor-specific properties.
Leitha
T
T
University Clinic of Nuclear Medicine, Vienna, Austria. THOMAS.LEITHA@akh-wien.ac.at
Glaser
C
C
Lang
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002455:Cell Division / Q000502:physiology; D018432:Drug Resistance, Multiple; D005260:Female; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017256:Technetium Tc 99m Sestamibi / Q000493:pharmacokinetics; D016159:Tumor Suppressor Protein p53 / Q000096:biosynthesis*
D019394:Ki-67 Antigen; D019275:Radiopharmaceuticals; D016159:Tumor Suppressor Protein p53; D017256:Technetium Tc 99m Sestamibi