A novel technique for in-vitro labelling of colonic cancer cells

Full text: The aim of this study was to determine a reliable method for labelling human colorectal tumour cells in order to study the movement of tumour cells in real-time during laparoscopic assisted colectomies in an animal model. The radiopharmaceutical technetium-99m hexamethylpropylene amine oxime (HMPAO) was used to radiolabel human colorectal tumour cells. The effects of temperature, incubation time and cell number were examined. Increasing incubation time and temperature showed that 99mTc-HMPAO accumulated more rapidly in cells, reaching a plateau in 15-30 minutes. Accumulation of 99mTc-HMPAO in tumour cells was lower at room temperature than at 37 deg C. 99mTc-HMPAO had the highest labelling efficiency (greater than 85%) with the largest number of cells (7x106) so that the maximum number of cells need to be used. As accumulation of 99mTc-HMPAO within the tumour cells did not greatly increase when incubation time increased from 15-30 minutes, it was concluded that optimal labelling of human colorectal tumour cells with 99mTc-HMPAO occurs at 15 minutes with incubation at 37 deg C. This cell labelling technique has been utilised in a scintigraphic model to determine the real-time movement of human colorectal tumour cells in a porcine model in vivo. This is to aid the evaluation of possible correlation between tumour recurrence at the site of the surgical scar of where the trocars were placed during the procedure via contamination of instruments used by 'spilled' tumour cells. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc