Invasive oxygen measurements and pimonidazole labeling in human cervix carcinoma

Purpose: This study was designed to compare tumor hypoxia assessed by invasive O-2 sensitive electrodes and pimonidazole labeling in primary human cervix carcinomas. Methods and Materials: Twenty-eight patients with primary cervix carcinomas (FIGO Stage Ib-IVa) were investigated,Both-invasive pO(2) measurements and pimonidazole labeling were obtained in all patients, Before treatment, patients were given pimonidazole as a single injection (0.5 g/m(2) i,v,), Ten to 24 h later, oxygenation measurements were done by Eppendorf histography, and after this procedure biopsies were taken for pimonidazole-binding analysis. Tumor oxygen partial pressure (pO(2)) was evaluated as the median tumor pO(2) and the fraction of pO(2) values less than or equal to 10 mmHg (HF10). Biopsies were formalin fixed and paraffin embedded, and hypoxia was detected by immunohistochemistry using monoclonal antibodies directed against reductively activated pimonidazole, Pimonidazole binding was evaluated by a semiquantitative scoring system. Results: Both Eppendorf measurements and pimonidazole binding showed large intra-and intertumor variability. A comparison between pimonidazole binding expressed as the fraction of fields at the highest score and HF10 showed a trend for the most well-oxygenated tumors having a low fraction of fields; however, the correlation did not reach statistical significance (p = 0,43, r = 0.165; Spearman's rank correlation test). Conclusion: Hypoxia measured in human uterine cervix carcinomas is heterogeneously expressed both within and between tumors when assessed by either invasive pO(2) measurements or pimonidazole binding. Despite a trend that tumors with high pO(2) values expressed less pimonidazole binding, no correlation was seen between the two assays In this preliminary report. (C) 2001 Elsevier Science Inc.