@article{LapaSchrederSchirbeletal.2017,
  author    = {Lapa, Constantin and Schreder, Martin and Schirbel, Andreas and Samnick, Samuel and Kort{\"u}m, Klaus Martin and Herrmann, Ken and Kropf, Saskia and Einsele, Herrmann and Buck, Andreas K. and Wester, Hans-J{\"u}rgen and Knop, Stefan and L{\"u}ckerath, Katharina},
  title     = {[\(^{68}\)Ga]Pentixafor-PET/CT for imaging of chemokine receptor CXCR4 expression in multiple myeloma - comparison to [\(^{18}\)F]FDG and laboratory values},
  series = {Theranostics},
  volume    = {7},
  journal   = {Theranostics},
  number    = {1},
  doi       = {10.7150/thno.16576},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-172106},
  pages     = {205-212},
  year      = {2017},
  abstract  = {Chemokine (C-X-C motif) receptor 4 (CXCR4) is a key factor for tumor growth and metastasis in several types of human cancer including multiple myeloma (MM). Proof-of-concept of CXCR4-directed radionuclide therapy in MM has recently been reported. This study assessed the diagnostic performance of the CXCR4-directed radiotracer [\(^{68}\)Ga]Pentixafor in MM and a potential role for stratifying patients to CXCR4-directed therapies. Thirty-five patients with MM underwent [\(^{68}\)Ga]Pentixafor-PET/CT for evaluation of eligibility for endoradiotherapy. In 19/35 cases, [\(^{18}\)F]FDG-PET/CT for correlation was available. Scans were compared on a patient and on a lesion basis. Tracer uptake was correlated with standard clinical parameters of disease activity. [\(^{68}\)Ga]Pentixafor-PET detected CXCR4-positive disease in 23/35 subjects (66\%). CXCR4-positivity at PET was independent from myeloma subtypes, cytogenetics or any serological parameters and turned out as a negative prognostic factor. In the 19 patients in whom a comparison to [\(^{18}\)F]FDG was available, [\(^{68}\)Ga]Pentixafor-PET detected more lesions in 4/19 (21\%) subjects, [\(^{18}\)F]FDG proved superior in 7/19 (37\%). In the remaining 8/19 (42\%) patients, both tracers detected an equal number of lesions. [\(^{18}\)F]FDG-PET positivity correlated with [\(^{68}\)Ga]Pentixafor-PET positivity (p=0.018). [\(^{68}\)Ga]Pentixafor-PET provides further evidence that CXCR4 expression frequently occurs in advanced multiple myeloma, representing a negative prognostic factor and a potential target for myeloma specific treatment. However, selecting patients for CXCR4 directed therapies and prognostic stratification seem to be more relevant clinical applications for this novel imaging modality, rather than diagnostic imaging of myeloma.},
  language  = {en}
}
@article{WernerKircherHiguchietal.2019,
  author    = {Werner, Rudolf A. and Kircher, Stefan and Higuchi, Takahiro and Kircher, Malte and Schirbel, Andreas and Wester, Hans-J{\"u}rgen and Buck, Andreas K. and Pomper, Martin G. and Rowe, Steven P. and Lapa, Constantin},
  title     = {CXCR4-directed imaging in solid tumors},
  series = {Frontiers in Oncology},
  volume    = {9},
  journal   = {Frontiers in Oncology},
  number    = {770},
  issn      = {2234-943X},
  doi       = {10.3389/fonc.2019.00770},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-195678},
  year      = {2019},
  abstract  = {Despite histological evidence in various solid tumor entities, available experience with CXCR4-directed diagnostics and endoradiotherapy mainly focuses on hematologic diseases. With the goal of expanding the application of CXCR4 theranostics to solid tumors, we aimed to elucidate the feasibility of CXCR4-targeted imaging in a variety of such neoplasms. Methods: Nineteen patients with newly diagnosed, treatment-na{\"i}ve solid tumors including pancreatic adenocarcinoma or neuroendocrine tumor, cholangiocarcinoma, hepatocellular carcinoma, renal cell carcinoma, ovarian cancer, and prostate cancer underwent [\(^{68}\)Ga]Pentixafor PET/CT. CXCR4-mediated uptake was assessed both visually and semi-quantitatively by evaluation of maximum standardized uptake values (SUV\(_{max}\)) of both primary tumors and metastases. With physiologic liver uptake as reference, tumor-to-background ratios (TBR) were calculated. [\(^{68}\)Ga]Pentixafor findings were further compared to immunohistochemistry and [\(^{18}\)F]FDG PET/CT. Results: On [\(^{68}\)Ga]Pentixafor PET/CT, 10/19 (52.6\%) primary tumors were visually detectable with a median SUVmax of 5.4 (range, 1.7-16.0) and a median TBR of 2.6 (range, 0.8-7.4), respectively. The highest level of radiotracer uptake was identified in a patient with cholangiocarcinoma (SUVmax, 16.0; TBR, 7.4). The relatively low uptake on [\(^{68}\)Ga]Pentixafor was also noted in metastases, exhibiting a median SUVmax of 4.5 (range, 2.3-8.8; TBR, 1.7; range, 1.0-4.1). A good correlation between uptake on [\(^{68}\)Ga]Pentixafor and histological derived CXCR4 expression was noted (R = 0.62, P < 0.05). In the 3 patients in whom [\(^{18}\)F]FDG PET/CT was available, [\(^{68}\)Ga]Pentixafor exhibited lower uptake in all lesions. Conclusions: In this cohort of newly diagnosed, treatment-na{\"i}ve patients with solid malignancies, CXCR4 expression as detected by [\(^{68}\)Ga]Pentixafor-PET/CT and immunohistochemistry was rather moderate. Thus, CXCR4-directed imaging may not play a major role in the management of solid tumors in the majority of patients.},
  language  = {en}
}