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Non-specific irreversible 89 Zr-mAb uptake in tumours: evidence from biopsy-proven target-negative tumours using 89 Zr-immuno-PET.
- Source :
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EJNMMI research [EJNMMI Res] 2024 Feb 15; Vol. 14 (1), pp. 18. Date of Electronic Publication: 2024 Feb 15. - Publication Year :
- 2024
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Abstract
- Background: Distribution of mAbs into tumour tissue may occur via different processes contributing differently to the <superscript>89</superscript> Zr-mAb uptake on PET. Target-specific binding in tumours is of main interest; however, non-specific irreversible uptake may also be present, which influences quantification. The aim was to investigate the presence of non-specific irreversible uptake in tumour tissue using Patlak linearization on <superscript>89</superscript> Zr-immuno-PET data of biopsy-proven target-negative tumours. Data of two studies, including target status obtained from biopsies, were retrospectively analysed, and Patlak linearization provided the net rate of irreversible uptake (K <subscript>i</subscript> ).<br />Results: Two tumours were classified as CD20-negative and two as CD20-positive. Four tumours were classified as CEA-negative and nine as CEA-positive. K <subscript>i</subscript> values of CD20-negative (0.43 µL/g/h and 0.92 µL/g/h) and CEA-negative tumours (mdn = 1.97 µL/g/h, interquartile range (IQR) = 1.50-2.39) were higher than zero. Median K <subscript>i</subscript> values of target-negative tumours were lower than CD20-positive (1.87 µL/g/h and 1.90 µL/g/h) and CEA-positive tumours (mdn = 2.77 µL/g/h, IQR = 2.11-3.65).<br />Conclusion: Biopsy-proven target-negative tumours showed irreversible uptake of <superscript>89</superscript> Zr-mAbs measured in vivo using <superscript>89</superscript> Zr-immuno-PET data, which suggests the presence of non-specific irreversible uptake in tumours. Consequently, for <superscript>89</superscript> Zr-immuno-PET, even if the target is absent, a tumour-to-plasma ratio always increases over time.<br /> (© 2024. The Author(s).)
Details
- Language :
- English
- ISSN :
- 2191-219X
- Volume :
- 14
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- EJNMMI research
- Publication Type :
- Academic Journal
- Accession number :
- 38358425
- Full Text :
- https://doi.org/10.1186/s13550-024-01079-5