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Purpose: [18F]fluorodeoxyglucose ([18F]FDG) positron emission tomography/computed tomography (PET/CT) has limitations in prostate cancer (PCa) detection owing to low glycolysis in the primary tumour. Recently, prostate-specific membrane antigen (PSMA) PET/CT has been useful for biochemical failure detection and radioligand therapy (RLT) guidance. However, few studies have evaluated its use in primary prostate tumours using PSMA and [18F]FDG PET/CT. This study aimed to evaluate [18F]PSMA-1007 and [18F]FDG PET/CT for primary tumour detection and understand the association of metabolic heterogeneity with clinicopathological characteristics at staging and postoperatively. Method: This prospective study included 42 index tumours (27 acinar and 15 ductal-dominant) in 42 patients who underwent [18F]PSMA-1007 and [18F]FDG PET/CT and subsequent radical prostatectomy. All patients were followed for a median of 26 mo, and serum prostate-specific antigen levels were measured every 3 mo to evaluate biochemical failure. One-way analysis of variance, Tukey's multiple comparison test, and Fisher's exact test were performed. Results: All 42 index tumours were detected on [18F]PSMA-1007 PET/CT, whereas only 15 were detected on [18F]FDG PET/CT (62.3% vs. 37.7%, p < 0.0001). A high SUVmax for [18F]PSMA-1007 was observed in tumours with high Gleason scores (GS 6–7 vs. GS 8–10; 12.1 vs. 20.1, p < 0.05). Tumours with [18F]FDG uptake were mostly ductal dominant (acinar-dominant 4/27; ductal-dominant; 11/15, p < 0.001), with lower [18F]PSMA-1007 uptake than tumours without [18F]FDG uptake (SUVmax 16.58 vs. 11.19, p < 0.001). There were 16.6% (7/42) of patients with pStage IV in whom the primary tumours were [18F]FDG positive. Biochemical failure was observed in 14.8% (4/27) of patients with [18F]FDG negative tumours but in 53.3% (8/15) of patients with [18F]FDG positive tumours (p = 0.013). Conclusions: [18F]PSMA-1007 PET/CT was superior to [18F]FDG PET/CT in detecting primary PCa. In contrast, tumours with [18F]FDG uptake are associated with larger size, a ductal-dominant type, and likely to undergo metastasis at staging and biochemical failure postoperatively. [ABSTRACT FROM AUTHOR]

Glucose utilization by visceral adipose tissue (VAT) reflects inflammatory activity, which also promotes tumor growth and carcinogenesis. The effect of metabolically active VAT on survival outcomes in breast cancer is unknown. We investigated survival outcomes in patients with breast cancer based on the standardized uptake value (SUV) of VAT (SUVmean-VAT) using 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT). A total of 148 patients with breast cancer were divided into high- and low groups according to their SUVmean-VAT and SUVmax-tumor. Clinical characteristics and survival outcomes were compared between the groups. High SUVmean-VAT was associated with poor recurrence-free survival (RFS; hazard ratio [HR], 2.754; 95% confidence interval [CI], 1.090–6.958, p = 0.032) and distant metastasis-free survival (DMFS; HR, 3.500; 95% CI, 1.224–10.01, p = 0.019). Multivariate analysis showed that high SUVmean-VAT was a significant factor for poor RFS and poor DMFS (p = 0.023 and 0.039, respectively). High SUVmax-tumor was significantly associated with short RFS (p = 0.0388). Tumors with a high SUV tended to have a short DMFS, although the difference was not significant (p = 0.0718). Our findings showed that upregulated glucose metabolism in the VAT measured using 18F-FDG PET/CT may be a prognostic biomarker for adverse outcomes in breast cancer. [ABSTRACT FROM AUTHOR]

Tenascin-C is an extracellular matrix glycoprotein strongly expressed in coronary atherosclerotic plaque. Aptamers are single-stranded oligonucleotides that bind to specific target molecules with high affinity. This study hypothesized that tenascin-C expression at atherosclerotic plaque in vivo could be detected by tenascin-C specific aptamers using positron emission tomography (PET). This paper reports the radiosynthesis of a fluorine-18 (18F)-labeled tenascin-C aptamer for the biodistribution and PET imaging of the tenascin-C expression in apolipoprotein E-deficient (ApoE−/−) mice. The aortas ApoE−/− mice showed significantly increased positive areas of Oil red O staining than control C57BL/6 mice, and tenascin-C expression was detected in foam cells accumulated in the subendothelial lesions of ApoE−/− mice. The ex vivo biodistribution of the 18F-labeled tenascin-C aptamer showed significantly increased uptake at the aorta of ApoE−/− mice, and ex vivo autoradiography of aorta revealed the high accumulation of the 18F-labeled tenascin-C aptamer in the atherosclerotic lesions of ApoE−/− mice, which was consistent with the location of the atherosclerotic plaques detected by Oil red O staining. PET imaging of the 18F-labeled tenascin-C aptamer revealed a significantly higher mean standardized uptake in the aorta of the ApoE−/− mice than the control C57BL/6 mice. These data highlight the potential use of tenascin-C aptamer to diagnose atherosclerotic lesions in vivo. • Tenascin-C expressed in the atherosclerotic lesions of aorta obtained from ApoE−/− mice. • Accumulation and retention of 18F-labeled TNC-specific aptamer in the aorta of ApoE−/− mice is higher than that of the control C57BL/6 mice. • Ex vivo autoradiography of 18F-labeled TNC-specific aptamer visualized the atherosclerotic lesions of aorta obtained from ApoE−/− mice. • PET imaging of 18F-labeled TNC-specific aptamer revealed a higher uptake in the aorta of the ApoE−/− mice than the control C57BL/6 mice. [ABSTRACT FROM AUTHOR]

Background/Purpose: Aptamers are oligonucleotide or peptide molecules that bind to a target molecule with high affinity and specificity. The present study aimed to evaluate the target specificity and applicability for in vivo molecular imaging of an aptamer labeled with a radioisotope. Methods: The human epidermal growth factor receptor 2 (HER2/ErbB2) aptamer was radiolabeled with 18F-fluoride. HER2-positive tumor cell uptake of the aptamer was evaluated in comparison to negative controls by flow cytometry and confocal microscopy. Using 18F-labeled HER2-specific aptamer positron emission tomography (PET), in vivo molecular images of BT474 tumor-bearing mice were taken at 60, 90 and 120 minutes after injection. Results: In flow cytometric analysis, HER2 aptamer showed strong binding to HER2-positive BT474 cells, while binding to HER2-negative MDA-MB231 cells was quite low. Likewise, in confocal microscopic images, the aptamer was bound to HER2-positive breast cancer cells, with minimal binding to HER2-negative cells. In vivo PET molecular imaging of BT474 tumor-bearing mice revealed significant higher uptake of the 18F-labeled HER2 specific aptamer into the tumor compared to the that of HER2-negative cell tumor(p = 0.033). HER2 aptamer was able to preferentially bind to HER2-positive breast cancer cells both in vitro and in vivo, by recognizing HER2 structure on the surface of these cells. Conclusion: The 18F-labeled aptamer enabled appropriate visualization of HER2 expression by human breast cancer cells. The results suggest that a radiolabeled HER2 aptamer could potentially be applied in the development of treatment strategies or in targeted therapy against HER2-positive breast cancer cells. [ABSTRACT FROM AUTHOR]

Background: Supradiaphragmatic lymph node metastases (SdLNM) are frequently identified using 18F-FDG positron emission tomography/computed tomography (PET/CT) in advanced epithelial ovarian cancers (AEOC). This study aimed to determine the prognostic significance of SdLNM detected by PET/CT in patients with AEOC.Methods: Medical records of patients diagnosed with AEOC were retrospectively registered from January 2009 to July 2015. Patients were categorized according to PET/CT stage: PET/CT stage III, PET/CT stage IV with SdLNM, and PET/CT stage IV with other metastases. Clinicopathologic characteristics, recurrence patterns, survival outcomes were compared according to PET/CT stage. Anatomical distribution of SdLNM and effect of thoracic debulking surgery were estimated.Results: A total of 295 patients were identified, including 176 patients who underwent primary debulking surgeries (PDS). Progression-free (P = 0.671) and overall (P = 0.525) survival did not differ significantly between patients with PET/CT IV with SdLNM and PET/CT IV with other metastases; however, patients with PET/CT IV with SdLNM had significantly poorer progression-free (P < 0.001) and overall (P = 0.016) survival than those with PET/CT stage III. Recurrence patterns were similar in all groups; intraperitoneal metastasis was the most common (78.8%) and thoracic recurrence alone accounted for less than 10%. Debulking of SdLNM lesions did not improve progression-free survival (P = 0.425) or overall survival (P = 0.465) of patients with AEOC.Conclusions: SdLNM detected using preoperative PET/CT are a negative prognostic factor in AEOC. Resection of suspicious SdLNM may not have effect to survival of patients with AEOC. [ABSTRACT FROM AUTHOR]

Abstract: This study was to investigate a hierarchical prognostic model using clinicopathological factors and 18F‐fludeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) for recurrence‐free survival (RFS) in patients with early breast cancer who underwent surgery without neoadjuvant chemotherapy. A total of 524 patients with early breast cancer were included. The Cox proportional hazards model was used with clinicopathological variables and maximum standardized uptake value (SUVmax) on PET/CT. After classification and regression tree (CART) modeling, RFS curves were estimated using the Kaplan–Meier method and differences in each risk layer were assessed using the log‐rank test. During a median follow‐up of 46.2 months, 31 (5.9%) patients experienced recurrence. The CART model identified four risk layers: group 1 (SUVmax ≤6.75 and tumor size ≤2.0 cm); group 2 (SUVmax ≤6.75 and Luminal A [LumA] or TN tumor >2.0 cm); group 3 (SUVmax ≤6.75 and Luminal B [LumB] or human epidermal growth factor receptor 2 [HER2]‐enriched] tumor >2.0 cm); group 4 (SUVmax >6.75). Five‐year RFS was as follows: 95.9% (group 1), 98% (group 2), 82.8% (group 3), and 85.4% (group 4). Group 3 or group 4 showed worse prognosis than group 1 or group 2 (group 1 vs. group 3: P = 0.040; group 1 vs. group 4: P < 0.001; group 2 vs. group 3: P = 0.016; group 2 vs. group 4: P < 0.001). High SUVmax (>6.75) in primary breast cancer was an independent factor for poor RFS. In patients with low SUVmax, LumB or HER2‐enriched tumor >2 cm was also prognostic for poor RFS, similar to high SUVmax. [ABSTRACT FROM AUTHOR]