True positive somatostatin receptor scintigraphy in primary breast cancer correlates with expression of sst2A and sst5.
[111In-DTPA-D-Phe1]-octreotide scintigraphy has been shown to reveal somatostatin receptor-positive lesions in the majority of primary breast cancers. We have recently developed a panel of somatostatin receptor subtype-specific antibodies that effectively stain formalin-fixed, paraffin-embedded breast cancer tissue. However, it is uncertain to what extend somatostatin receptors detected during immunohistochemical staining represent functional binding sites responsible for high tracer uptake during somatostatin receptor scintigraphy.


METHODS
We, therefore, conducted a prospective study in which 23 patients with suspected breast tumors were included. All patients received [111In]-pentetreotide scintigraphy. After surgical removal of the tumor, the somatostatin receptor status was determined by immunohistochemistry.


RESULTS
Among 20 pathologically proven malignant tumors (14 ductal and six lobular carcinomas), 13 (approximately 65%) were scintigraphically visible. Of the 20 primary breast cancer specimens analyzed, three tumors (approximately 15%) were positive for sst1, nine (approximately 45%) revealed immunoreactive sst2A receptors, eight (approximately 40%) showed sst3-like immunoreactivity, and 14 (approximately 70%) were positive for sst5. There was an excellent correlation between the outcome of somatostatin receptor scintigraphy and expression of sst2A (P = 0.025) as well as sst5 (P < 0.001) but not expression of either sst1 (P = 0.343) or sst3 (P = 0.400).


CONCLUSIONS
Both sst2A and sst5 can be responsible for high tracer uptake during [111In]-pentetreotide scintigraphy in primary breast cancer. Thus, somatostatin receptor scintigraphy may possibly be of value in the detection of proven somatostatin receptor sst2A- and/or sst5-positive lesions in metastatic breast cancer.
Schulz
Solveig
S
Department of Obstetrics and Gynecology, Otto-von-Guericke-University, Magdeburg, Germany. Solveig.Schulz@Medizin.Uni-Magdeburg.de
Helmholz
Thekla
T
Schmitt
Johannes
J
Franke
Kornelia
K
Otto
Hans-Jürgen
HJ
Weise
Wolfgang
W
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007205:Indium Radioisotopes; D008875:Middle Aged; D015282:Octreotide / Q000031:analogs & derivatives*; D004369:Pentetic Acid / Q000031:analogs & derivatives*; D011446:Prospective Studies; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000032:analysis*
D015415:Biomarkers; D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; C106140:somatostatin receptor sst2A; C071632:SDZ 215-811; D004369:Pentetic Acid; C094573:somatostatin receptor 5; D015282:Octreotide