COMPARISON OF 2 TECHNIQUES FOR DETECTING TUMOR-HYPOXIA - A FLUORESCENT IMMUNOCHEMICAL METHOD AND AN IN-VITRO COLONY ASSAY

The aim of this study was to compare the percentage of hypoxic cells o btained with two methods: an in vitro colony assay and a new method ba sed on immunodetection of a marker for hypoxic cells (NITP) which coul d be used in patients. These studies have been carried out using one r odent tumour EMT6 (a mammary carcinoma) and one human tumour HRT18 (a rectal adenocarcinoma). The hypoxic cell fraction was assessed in cont rol mice and in mice receiving two treatments: 250 mg/kg nicotinamide + carbogen, and 250 mg/kg nicotinamide + carbogen + 4 ml/kg perflubron emulsion. The two treatments increased the radiosensitivity of the tw o cell lines, nicotinamide plus carbogen plus perflubron emulsion havi ng the greatest radiosensitising effect. For untreated and treated tum ours, the percentage of hypoxic cells obtained with the in vitro colon y assay were comparable to those obtained with immunodetection using N ITP. Whatever the treatment, NITP detection was a convenient test to d etect the hypoxic cell fraction in the two solid tumours we have studi ed.