Increased choline uptake in macrophages and prostate cancer cells does not allow for differentiation between benign and malignant prostate pathologies

PET Imaging in Bladder Cancer: An Update and Future Direction

Molecular imaging with positron emission tomography is a powerful tool in bladder cancer management. In this review, we aim to address the current place of the PET imaging in bladder cancer care and offer perspectives on potential future radiopharmaceutical and technological advancements. A special focus is given to the following: the role of [¹⁸F] 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography in the clinical management of bladder cancer patients, especially for staging and follow-up; treatment guided by [¹⁸F]FDG PET/CT; the role of [¹⁸F]FDG PET/MRI, the other PET radiopharmaceuticals beyond [¹⁸F]FDG, such as [⁶⁸Ga]- or [¹⁸F]-labeled fibroblast activation protein inhibitor; and the application of artificial intelligence.

18F-Fluorocholine Uptake by a Head and Neck Meningeal Inflammatory Pseudotumor

F-Fluoro-ethyl-choline (F-FCH) PET/CT is widely used to study patients affected by prostate cancer. However, F-FCH may be taken-up by other neoplastic diseases, infections, and non-infective inflammatory processes. While this behavior may be an opportunity to study different diseases, on the other hand, this condition brings with it the source of error in the evaluation of the images. Here we present the case of a meningeal inflammatory pseudotumor evidenced by F-FCH.

Choline Uptake and Metabolism Modulate Macrophage IL-1β and IL-18 Production

Choline is a vitamin-like nutrient that is taken up via specific transporters and metabolized by choline kinase, which converts it to phosphocholine needed for de novo synthesis of phosphatidylcholine (PC), the main phospholipid of cellular membranes. We found that Toll-like receptor (TLR) activation enhances choline uptake by macrophages and microglia through induction of the choline transporter CTL1. Inhibition of CTL1 expression or choline phosphorylation attenuated NLRP3 inflammasome activation and IL-1β and IL-18 production in stimulated macrophages. Mechanistically, reduced choline uptake altered mitochondrial lipid profile, attenuated mitochondrial ATP synthesis, and activated the energy sensor AMP-activated protein kinase (AMPK). By potentiating mitochondrial recruitment of DRP1, AMPK stimulates mitophagy, which contributes to termination of NLRP3 inflammasome activation. Correspondingly, choline kinase inhibitors ameliorated acute and chronic models of IL-1β-dependent inflammation.

Inverse Association of Prostatic Chronic Inflammation among Prostate Cancer Tumor Grade Groups: Retrospective Study of 738 Consecutive Cases Elected to a First Random Biopsy Set

OBJECTIVES

The study aimed to evaluate associations of prostatic chronic inflammation (PCI) with prostate cancer (PCA) grade groups by the International Society of Urological Pathology (ISUP).

METHODS

The study evaluated retrospectively 738 cases. The patient population was sampled into 3 groups collecting cases without and with PCA including subjects with lSUP grade group 1 and grade groups 2-5.

RESULTS

PCI was assessed in 185 patients (25.1%) and PCA in 361 patients (48.9%) of whom 188 (25.5%) had ISUP grade and 173 (23.4%) had ISUP groups 2-5 tumors. PCI inversely related to ISUP groups (p < 0.0001). In multivariate analysis, the risk of ISUP grade group 1 PCA compared to negative cases associated positively with age (OR 1.042; p = 0.001) but inversely with total prostate volume (TPV; OR 0.965; p < 0.0001) and PCI (OR 0.314; p < 0.0001). Intermediate-high grade tumors associated positively with age (OR 1.065; p < 0.0001), prostate specific antigen (OR 1.167; p < 0.0001), and abnormal digital rectal examination (OR 2.251; p < 0.0001) but inversely with TPV (OR 0.921; p < 0.0001) and PCI (OR 0.106; p < 0.0001).

CONCLUSIONS

PCI decreased the risk of PCA among ISUP tumor grade groups.

PET Tracer 18F-Fluciclovine Can Detect Histologically Proven Bone Metastatic Lesions: A Preclinical Study in Rat Osteolytic and Osteoblastic Bone Metastasis Models

¹⁸F-Fluciclovine (trans-1-amino-3-¹⁸F-fluorocyclobutanecarboxylic acid; anti-¹⁸F-FACBC) is a positron emission tomography (PET) tracer for diagnosing cancers (e.g., prostate and breast cancer). The most frequent metastatic organ of these cancers is bone. Fluciclovine-PET can visualize bony lesions in clinical practice; however, such lesions have not been described histologically. Methods: We investigated the potential of ¹⁴C-fluciclovine in aiding the visualization of osteolytic and osteoblastic bone metastases (with histological analyses), compared with ³H-2-deoxy-2-fluoro-D-glucose (³H-FDG), ³H-choline chloride (³H-choline), and ^99mTc-hydroxymethylene diphosphonate (^99mTc-HMDP) by using triple-tracer autoradiography in rat breast cancer osteolytic (on day 12 ± 1 postinjection of MRMT-1) and prostate cancer osteoblastic (on day 20 ± 3 postinjection of AT6.1) metastatic models. Results: The distribution patterns of ¹⁴C-fluciclovine, ³H-FDG, and ³H-choline, but not ^99mTc-HMDP, were similar in both models, and the lesions where these tracers accumulated were, histologically, typical osteolytic and osteoblastic lesions. ^99mTc-HMDP accumulated mostly in osteoblastic lesions. ¹⁴C-fluciclovine could visualize the osteolytic lesions as early as day 6 postinjection of MRMT-1. However, differential distributions in ¹⁴C-fluciclovine and ³H-FDG existed, based on histological differences: low ¹⁴C-fluciclovine and high ³H-FDG accumulation in osteolytic lesions with inflammation. In the osteoblastic metastatic model, visualization of osteoblastic lesions with ¹⁴C-fluciclovine was not clear, yet clearer than with ³H-FDG. Although half of the osteoblastic lesions with ¹⁴C-fluciclovine accumulation showed negligible ³H-choline accumulation in comparison, they were histologically similar to lesions with marked ¹⁴C-fluciclovine and ³H-choline accumulation. Conclusion: These results suggest that fluciclovine-PET can visualize true osteolytic and osteoblastic bone metastatic lesions.