Somatostatin receptor subtype 2-mediated scintigraphy and localization using 99mTc-HYNIC-Tyr~3-octreotide in human hepatocellular carcinoma-bearing nude mice

AIM: To investigate the uptake of 99mTc-HYNIC-Tyr3-octreotide (99mTc-HYNIC-TOC) in human hepatocellular carcinoma (HCC), which can provide the localizable diagnosis in hepatic carcinoma. METHODS: The expression of somatostatin receptor 2 (SSTR2) messenger RNA (mRNA) in human HCC cell line HepG2 was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). Uptake of 99mTc-HYNIC-TOC was evaluated in the human HCC implanted into BALB/c nude mice. ANMIS2000 nuclear medicine analysis system was used to calculate the ratio of 99mTc uptake between tumor tissue and vital organs. RESULTS: We demonstrated the expression of SSTR2 mRNA in human HCC cell line HepG2 by RT-PCR. The size of the RT-PCR products was 364 bp detected by sequence analysis of the human SSTR2 mRNA. Scintigraphy proved that 99mTc-HYNIC-TOC was uptaken in the tumor tissue, liver and kidney of the tumor-bearing mice. CONCLUSION: Based on expression of the SSTR2 mRNA in human HCC, 99mTc-HYNIC-TOC can markedly bind with and be uptaken by human HCC tissues as compared with normal liver tissue. The significant retention of radionudide in kidney and bladder is probably related to non-specific peptide uptake in the tubulus cells of kidney and possibly due to excretion by kidney. Our results show that localizable diagnosis and targeting radiotherapy with radionuclide-labeled somatostatin analog for HCC are of great value to be further studied.