Quantitative assessment of 99mTc-depreotide uptake in patients with non-small-cell lung cancer: immunohistochemical correlations.
BACKGROUND
Somatostatin receptor (SSTR) scintigraphy with (99m)Tc-depreotide is used for differential diagnosis of solitary pulmonary nodules. The method is based on SSTR expression in cancer tissue.


OBJECTIVE
To estimate the expression of SSTRs in non-small-cell lung cancer (NSCLC) in vitro, and to determine the correlation between (99m)Tc-depreotide uptake in vivo and different tumor characteristics determined in vitro, such as tumor grade, and presence of SSTR2, MIB-1, and p53.


METHODS
A total of 127 patients with lung lesions detected on computed tomography (CT) were investigated with SSTR scintigraphy after injection of 740 MBq (99m)Tc-depreotide. This study includes 19 patients with NSCLC with histologically proven diagnosis. The quantitative evaluation of (99m)Tc-depreotide was performed using region-of-interest analysis and includes tumor counts/cm(3), background counts/cm(3), and the ratio between tumor and background counts.


RESULTS
99mTc-depreotide uptake was found in all NSCLC tumors, which expressed SSTR2 defined in vitro by immunochemical methods. SSTR2 expression was negatively correlated to the degree of the tumor's differentiation (P<0.05). 99mTc-depreotide uptake in tumor cells did not correlate with tumor grade, or SSTR2, MIB-1, or p53 expression.


CONCLUSIONS
There is an expression of SSTRs in NSCLC. The degree of tumor differentiation correlates negatively with SSTR2 measured in vitro and positively with MIB-1 expression in tumor tissue. No correlation was found between (99m)Tc-depreotide uptake and possible prognostic factors such as MIB-1 and p53 expression in tumor cells in NSCLC. Lastly, no correlation was found between (99m)Tc-depreotide uptake and tumor grade or SSTR2 expression.
Herlin
G
G
Department of Clinical Science, Intervention, and Technology, Division of Radiology, Karolinska Institute at Campus Huddinge, Karolinska University Hospital, Huddinge, Stockholm, Sweden. gunnar.herlin@karolinska.se
Kölbeck
K-G
KG
Menzel
P L
PL
Svensson
L
L
Aspelin
P
P
Capitanio
A
A
Axelsson
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000378:metabolism; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
D015609:Organotechnetium Compounds; D017481:Receptors, Somatostatin; D013004:Somatostatin; C444119:technetium Tc 99m depreotide