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Case studies of 32, 62 and 75 years patients are presented with relapsed refractory multiple myeloma, diffuse large B cell lymphoma, and acute lymphoblastic leukaemia. C-X-C-motif chemokine receptor 4 (CXCR4)-directed treatment was offered on a compassionate use basis prior to stem cell transplantation; and initial CXCR4-expression was confirmed in all patients using Pentixafor positron emission tomography/computed tomography and immunohistochemical analysis.

The article discusses a prospective study which investigated the emergence of L-methyl-C methionine (MET) as a new biomarker for monitoring active myeloma lesions. Involved in the study were ten patients with biopsy-proven multiple myeloma who underwent molecular imaging using positron emission tomography (PET) with a radiolabelled glucose analogue for diagnosis. The study has shown the potential superiority of the amino acid MET for staging multiple myeloma.

CXCR4 is a G-protein-coupled receptor that mediates recruitment of blood cells toward its ligand SDF-1. In cancer, high CXCR4 expression is frequently associated with tumor dissemination and poor prognosis. We evaluated the novel CXCR4 probe [68Ga]Pentixafor for in vivo mapping of CXCR4 expression density in mice xenografted with human CXCR4-positive MM cell lines and patients with advanced MM by means of positron emission tomography ( PET). [68Ga]Pentixafor PET provided images with excellent specificity and contrast. In 10 of 14 patients with advanced MM [68Ga]Pentixafor PET/ CT scans revealed MM manifestations, whereas only nine of 14 standard [18F]fluorodeoxyglucose PET/ CT scans were rated visually positive. Assessment of blood counts and standard CD34+ flow cytometry did not reveal significant blood count changes associated with tracer application. Based on these highly encouraging data on clinical PET imaging of CXCR4 expression in a cohort of MM patients, we conclude that [68Ga]Pentixafor PET opens a broad field for clinical investigations on CXCR4 expression and for CXCR4-directed therapeutic approaches in MM and other diseases. [ABSTRACT FROM AUTHOR]