Abstract: Objective To evaluate the value of ^99mTc-octreotide somatostatin receptor (SSTR) scintig-raphy in breast cancer.Methods 15 breast cancer patients underwent ^99mTc-octreotide SSTR scintigraphy before surgery, and tumor to normal tissue ratio (T/N) was calculated. mRNA expression of SSTR 1, SSTR2, SSTR3, SSTR4, SSTR5 was detected by RT-PCR after surgery. And SSTR2 and SSTR5 expressions were detected by immunohistochemical staining in these 15 breast carcinoma as well as other 18 benign breast tissue.Results All of the 15 breast cancer patients showed intense uptake of ^99mTc-octreotide, and T/N values were 1.873±0.341. All five SSTR sub-types were variably expressed at the mRNA level in breast cancer with 100% (15/15)amplesshowing SSTR1, 93.30% (14/15) SSTR2, 100% (15/15) SSTR3, 46.70% (7/15)SSTR4 and 86.70% (13/15)SSTR5. Levels of SSTR mRNA, when corrected for glyeraldehyde 3-phosphaate dehydrogenase gene levels, were highest for SSTR3 followed by SSTR1, SSTR2, SSTR5, and SSTR4. Good correlation was obtained between the ratio of T/N and the expression of SSTR2 mRNA (r=0.728, P<0.01). Both the expression of SSTR2 and SSTR5 are higher in malignant ones than in benign breast tissues.Conclusion The results indicate that there was high expression of SSTR in breast cancer. SSTR scintigraphy is of great value in targeted detection of breast cancer.