The Role of Adipocytokines and their Receptors in Prostate Cancer: Adiponectin May Protect Against Progression

BACKGROUND/AIM

Obesity is correlated with an increased risk of developing malignancies, including prostate cancer. Adipocytokines, such as leptin and adiponectin, are a family of hormones derived from adipose tissue that are involved not only in metabolism, but also in the development and progression of various malignancies. However, little is known about their role in prostate cancer. This study aimed to determine how leptin, adiponectin, and their receptors impact the spread of prostate cancer.

MATERIALS AND METHODS

We first performed immunohistochemical analysis of prostate cancer tissue microarrays to detect leptin, leptin receptor (Ob-R), adiponectin, and adiponectin receptors 1 and 2 (AdipoR1 and AdipoR2). Wound healing assays and western blot analysis were then performed in human prostate cancer cell lines.

RESULTS

Immunohistochemistry showed that prostate tissue was not significantly positive for adiponectin. However, its expression tended to decrease according to the International Society of Urological Pathology (ISUP) grade of prostate cancer (p=0.056). In prostate cancer cell lines, administration of the synthetic adiponectin AdipoRon suppressed cell migration as well as the expression of phospho-NF-[Formula: see text]B and cyclooxygenase-2, whereas leptin stimulated these effects.

CONCLUSION

Adiponectin expression tended to be suppressed according to ISUP grade in prostate cancer tissues. In vitro, tumor cell migration was induced by leptin but suppressed by adiponectin. Targeting adipocytokines could be a novel treatment strategy for prostate cancer.

Fusion-targeted biopsy significantly improves prostate cancer detection in biopsy-naïve men

OBJECTIVE

The precise diagnosis of prostate cancer (PC) is crucial to avoid underdiagnosis, overdiagnosis, and overtreatment. We aimed to compare clinically significant PC (csPC) detection between MRI/ultrasound fusion-targeted prostate (TBx) compared to systematic biopsy (SBx) in biopsy-naïve Japanese men.

METHODS

We included patients with suspect PC due to elevated PSA level or abnormal digital rectal examination, or both. csPC was defined as International Society Urological Pathology (ISUP) grade group ≥2 (csPC-A) and ISUP grade group ≥3 (csPC-B).

RESULTS

This study included 143 patients. Overall PC detection was 66.4% for SBx and 67.8% for MRI-TBx. MRI-TBx presented a significantly higher rate of csPC detection (csPC-A 67.1% vs. 58.7%, p = 0.04, and csPC-B 49.6% vs. 39.9%, p < 0.001) and significantly lower detection of non-csPC-A (0.6% vs. 6.7%). Importantly, MRI-TBx missed 4.9% (7/143) of csPC-A and only 0.7% (1/143) of csPC-B. On the other hand, SBx alone missed 13.3% (19/143) of csPC-A and 4.2% (6/143) of csPC-B.

CONCLUSION

MRI-TBx significantly outperformed 12-cores SBx for csPC detection and decreased non-csPC detection in biopsy-naive men. Performing MRI-TBx without SBx would have missed some csPC, supporting that MRI-TBx synergizes with SBx to increase csPC detection.

Prognostic impact of CD73/adenosine 2A receptor (A2AR) in renal cell carcinoma and immune microenvironmental status with sarcomatoid changes and rhabdoid features

One of the most aggressive forms of kidney cancer is renal cell carcinoma (RCC) with sarcomatoid changes and rhabdoid features (S/R). Adenosine produced via CD73 binds to adenosine 2 A receptor (A2AR) and suppress antitumor immunity. Here, we attempted to analyze the expression of CD73/A2AR in S/R RCC and examined its relationships with other immune microenvironments and prognostic effect. Sixty cases of S/R RCC were selected. CD73/A2AR expression levels were graded in the tumor cells or infiltrating immune cells on a score of 0-3 and divided into low (0 or 1) or high (2 or 3) groups. PD-L1 results were defined by the tumor proportion score (TPS). We counted the numbers of CD8⁺, FOXP3⁺, CD68⁺, and CD163⁺ immune cells. The rates of CD73/A2AR expression in epithelial component (23.3% and 15.0%) were lower than those in high-grade component (70.0% and 45.0%). CD73/A2AR were significantly correlated to high numbers of regulatory Tcells and macrophages of M2 subtype (CD73: P = 0.0059 and 0.0002; A2AR: P = 0.0002 and 0.018, respectively). Multivariate analysis showed that CD73/A2AR expressions were independent markers of unfavorable prognosis in S/R RCCs (P = 0.0204 and 0.0116, respectively). In RCC, the S/R component had higher expressions of CD73/A2AR than the epithelial component, and CD73/A2AR were independent prognostic factors. Compared with other RCCs, S/R RCCs are more effective at blocking adenosine signaling and CD73/A2AR inhibitors are expected to enhance the therapeutic efficacy and improve the prognosis of immune checkpoint inhibitor therapies.

TFE3-immunopositive papillary renal cell carcinoma: A clinicopathological, immunohistochemical, and genetic study

It is possible that PRCCs may still contain a variety of unknown histologic subtypes. Some PRCCs express high expression of TFE3 protein without TFE3 gene rearrangement, but no reports have investigated the significance of this. Here we attempted to examine clinicopathological and molecular significance of the TFE3-immunopositive PRCC. We reviewed the histology and immunohistochemistry in 58 PRCCs. TFE3 immunoexpression was recognized in 7 cases. Because TFE3 immunostaining shows false-positive, to ensure the integrity of TFE3 immunostaining, the immunostaining was performed under strict control of internal controls and western blotting was performed on 2 positive cases and 5 negative cases, and differences in protein expression between two groups were confirmed. Significant immunohistochemical expressions of autophagy/lysosome proteins were observed in TFE3-positive group. No TFE3 gene arrangement was detected in all positive cases by fluorescence in situ hybridization. Whole-exome sequencing was performed on 6 TFE3-positive and 2 TFE3-negative cases. Gain of chromosome 7 was found in five of 6 TFE3-positive cases (83%). TFE3-positive group was correlated significantly with higher pTstage, cNstage, WHO/ISUP nuclear grade, and decreased OS. TFE3-immunopositive PRCC group had a poorer prognosis than TFE3-negative PRCC group and showed correlation with expressions of autophagy/lysosome proteins, suggesting that enhancement of autophagy/lysosome function drives an environment of energy metabolism that is favorable for cancer. It is necessary to recognize that there is TFE3-immunopositive group without TFE3 gene rearrangement within PRCC. Because of its aggressive biological behaviour, TFE3 can act as a biomarker in PRCC; moreover, autophagy-inhibiting drugs may have therapeutic effects on TFE3-immunopositive PRCC.

Correlation between extended pelvic lymph node dissection and urinary incontinence at early phase after robot‐assisted radical prostatectomy

OBJECTIVES

To investigate the impact of extended pelvic lymph node dissection (ePLND) on urinary incontinence (UI) at early post-surgery robot-assisted radical prostatectomy (RARP).

METHODS

Patients who underwent RARP without cavernous nerve sparing were included between 2014 and 2019. Patient data were obtained prospectively. The associations between ePLND and postoperative urinary continence were defined as a maximum of one daily pad use. International prostate symptom score (IPSS) was examined. Expression of synaptophysin and tyrosine hydroxylase (TH) in perilymph node adipose tissue (PLA) was evaluated by immunohistochemistry.

RESULTS

In total, 186 and 163 patients underwent RARP with and without ePLND. Urinary continence rate at 1 month postoperatively among patients with ePLND was lower than those without ePLND (24.1% vs. 35.1%, p < 0.05), however, not significantly different at 3, 6, and 12 months after RARP (57.4 vs. 62.6%, 73.1 vs. 74.2%, and 83.0 vs. 81.2%, respectively). Total and voiding plus postvoiding IPSS scores at 1 month were higher in patients with ePLND than in those without ePLND (14.5 ± 0.5 vs. 13.6 ± 0.6, 7.0 ± 0.3 vs. 6.2 ± 0.4, respectively, p < 0.05). In univariate and multivariate analyses, larger prostate volume and ePLND were factors associated with an increased UI rate. Among patients who underwent ePLND, synaptophysin and TH-positive nerve fibers were detected in PLA.

CONCLUSIONS

Detection of synaptophysin and TH-immunopositive nerves suggested denervation of sympathetic and peripheral nerves caused by ePLND might be associated with a higher UI rate and poor urinary symptoms at an early stage after RARP.

Activated protein kinase C-alpha as a simple test for urothelial cancer screening

e16552

Background: The development of a non-invasive, highly predictive diagnostic test for urothelial cancer (UC) would greatly benefit patients. Although numerous urine-based tests have been developed, it is not widely used, except for urine cytology, due to insufficient sensitivity, negative predictive value and high cost. Previously we reported that protein kinase C-alpha (PKCα) is overexpressed or activated in several cancer tissues but not in normal tissue, and we developed an activated PKCα-specific peptide substrate (FKKQGSFAKKK; Patent No. 5476559). The purpose of this study was to investigate the potential for UC screening of simple test detecting activated PKCα. Methods: This institutional review board-approved prospective study included patients with bladder cancer or upper urinary tract UC who underwent surgery at Kyushu University Hospital between September 2018 and December 2020. Patients with benign urologic disorders or healthy volunteers were included as a control group. Patients with prostate cancer (PC) or renal cell carcinoma (RCC) who underwent curative surgery were included as other genitourinary (GU) cancer group. Patients with other coexisting malignant tumors were excluded. Urine samples were collected prior to surgery, 20 mL of urine was centrifuged, and the pellet was lysed for analysis. We evaluated the phosphorylation status of the activated PKCα-specific peptide substrate by MALDI-TOF mass spectrometry. The utility of activated PKCα as a urinary biomarker was evaluated by its sensitivity and negative predictive value when compared to control group or other GU cancers group. Results: Urine samples were obtained from 226 individuals, which included 98 patients with UC, 51 with other GU caners, and 77 with control group. Of the 98 patients with UC, activated PKCα was detected in 75 patients, with sensitivity of 76.5%. The sensitivity in patients with high-grade and low-grade UC were 84% and 62%, respectively. The sensitivity in those with high-grade UC increased to 93% when combined with urine cytology. On the other hand, activated PKCα were rarely detected in non-UC patients which includes other GU cancers group and control group. The specificity among the non-UC patients was 74.2%. In the comparison between patients with UC and non-UC, the negative predictive value of activated PKCα was 80.5%. The area under the receiver operating characteristic curve (AUC) for detecting UC of activated PKCα was 0.80. Conclusions: This study demonstrates the utility of activated PKCα as a novel urine screening test for UC. (Patent Application No. PCT/JP2020/045257) Since this test is based on a single target, inexpensive detection devices can be developed.

Stratification of prostate cancer patients into low- and high-grade groups using multiparametric magnetic resonance radiomics with dynamic contrast-enhanced image joint histograms

PURPOSE

This study aimed to investigate the potential of stratification of prostate cancer patients into low- and high-grade groups (GGs) using multiparametric magnetic resonance (mpMR) radiomics in conjunction with two-dimensional (2D) joint histograms computed with dynamic contrast-enhanced (DCE) images.

METHODS

A total of 101 prostate cancer regions extracted from the MR images of 44 patients were identified and divided into training (n = 31 with 72 cancer regions) and test datasets (n = 13 with 29 cancer regions). Each dataset included low-grade tumors (International Society of Urological Pathology [ISUP] GG ≤ 2) and high-grade tumors (ISUP GG ≥ 3). A total of 137,970 features consisted of mpMR image (16 types of images in four sequences)-based and joint histogram (DCE images at 10 phases)-based features for each cancer region. Joint histogram features can visualize temporally changing perfusion patterns in prostate cancer based on the joint histograms between different phases or subtraction phases of DCE images. Nine signatures (a set of significant features related to GGs) were determined using the best combinations of features selected using the least absolute shrinkage and selection operator. Further, support vector machine models with the nine signatures were built based on a leave-one-out cross-validation for the training dataset and evaluated with receiver operating characteristic (ROC) curve analysis.

RESULTS

The signature showing the best performance was constructed using six features derived from the joint histograms, DCE original images, and apparent diffusion coefficient maps. The areas under the ROC curves for the training and test datasets were 1.00 and 0.985, respectively.

CONCLUSION

This study suggests that the proposed approach with mpMR radiomics in conjunction with 2D joint histogram computed with DCE images could have the potential to stratify prostate cancer patients into low- and high-GGs.

Artificial intelligence for segmentation of bladder tumor cystoscopic images performed by U-Net with dilated convolution

BACKGROUND

Early intravesical recurrence after transurethral resection of bladder tumors (TURBT) is often caused by overlooking of tumors during TURBT. Although narrow-band imaging and photodynamic diagnosis were developed to detect more tumors than conventional white-light imaging, the accuracy of these systems has been subjective, along with poor reproducibility due to their dependence on the physician's experience and skills. To create an objective and reproducible diagnosing system, we aimed to assess the utility of artificial intelligence (AI) with Dilated U-Net to reduce the risk of overlooked bladder tumors when compared with the conventional AI system, termed U-Net.

MATERIAL AND METHODS

We retrospectively obtained cystoscopic images by converting videos obtained from 120 patients who underwent TURBT into 1,790 cystoscopic images. The Dilated U-Net, which is an extension of the conventional U-Net, analyzed these image datasets. The diagnostic accuracy of the Dilated U-Net and conventional U-Net were compared using the following four measurements: pixel-wise sensitivity (PWSe); pixel-wise specificity (PWSp); pixel-wise positive predictive value (PWPPV), representing the AI diagnostic accuracy per pixel; and dice similarity coefficient (DSC), representing the overlap area between the bladder tumors in the ground truth images and segmentation maps.

RESULTS

The cystoscopic images were divided as follows, according to the pathological T-stage: 944, Ta; 412, T1; 329, T2; and 116, carcinoma in-situ. The PWSe, PWSp, PWPPV, and DSC of the Dilated U-Net were 84.9%, 88.5%, 86.7%, and 83.0%, respectively, which had improved when compared to that with the conventional U-Net by 1.7%, 1.3%, 2.1%, and 2.3%, respectively. The DSC values were high for elevated lesions and low for flat lesions for both Dilated and conventional U-Net.

CONCLUSIONS

Dilated U-Net, with higher DSC values than conventional U-Net, might reduce the risk of overlooking bladder tumors during cystoscopy and TURBT.

Clinical impact of HSD3B1 polymorphism by metastatic volume and somatic HSD3B1 alterations in advanced prostate cancer

This study aimed to investigate the significance of HSD3B1 gene status including germline polymorphism and somatic alterations in prostate cancer. Patients with prostate cancer treated with androgen-deprivation therapy, as well as tissues from metastatic prostate cancer, were included. Genomic DNA was extracted from cancer tissues and whole blood samples, and HSD3B1 (rs1047303, 1245C) was genotyped by Sanger sequencing. The association of HSD3B1 genotype with progression-free survival according to metastatic volume was examined. Copy number alteration and gene expression of HSD3B1 were examined in prostate cancer cells and public datasets. Among 194 patients, 121 and 73 patients were categorized into low- and high-volume diseases respectively. In multivariate analysis, the adrenal-permissive genotype (AC/CC) was significantly associated with increased risk of progression compared with the adrenal-restrictive genotype (AA) in low volume, but not high-volume diseases. Somatic mutation in HSD3B1 was detected at least in two cases of castration-resistant prostate cancer tissues. HSD3B1 amplification and overexpression were detected in castration-resistant prostate cancer cells and tissues. The current findings suggest that both germline and somatic alterations of HSD3B1 may cooperatively promote castration resistance in prostate cancer and HSD3B1 as a promising biomarker for precision medicine, warranting further investigations.

The Japan-Multimodal Intervention Trial for Prevention of Dementia (J-MINT): The Study Protocol for an 18-Month, Multicenter, Randomized, Controlled Trial

Background/Objectives

The Japan-multimodal intervention trial for prevention of dementia (J-MINT) is intended to verify the effectiveness of multi-domain interventions and to clarify the mechanism of cognitive improvement and deterioration by carrying out assessment of dementia-related biomarkers, omics analysis and brain imaging analysis among older adults at high risk of dementia. Moreover, the J-MINT trial collaborates with partnering private enterprises in the implementation of relevant interventional measures. This manuscript describes the study protocol.

Design/Setting

Eighteen-month, multi-centered, randomized controlled trial.

Participants

We plan to recruit 500 older adults aged 65–85 years with mild cognitive impairment. Subjects will be centrally randomized into intervention and control groups at a 1:1 allocation ratio using the dynamic allocation method with all subjects stratified by age, sex, and cognition.

Intervention

The multi-domain intervention program includes: (1) management of vascular risk factors; (2) group-based physical exercise and self-monitoring of physical activity; (3) nutritional counseling; and (4) cognitive training. Health-related information will be provided to the control group every two months.

Measurements

The primary and secondary outcomes will be assessed at baseline, 6-, 12-, and 18-month follow-up. The primary outcome is the change from baseline to 18 months in a global composite score combining several neuropsychological domains. Secondary outcomes include: cognitive change in each neuropsychological test, incident dementia, changes in blood and dementia-related biomarkers, changes in geriatric assessment including activities of daily living, frailty status and neuroimaging, and number of medications taken.

Conclusions

This trial that enlist the support of private enterprises will lead to the creation of new services for dementia prevention as well as to verify the effectiveness of multi-domain interventions for dementia prevention.

Electronic Supplementary Material

Supplementary material is available for this article at 10.14283/jpad.2021.29 and is accessible for authorized users.

A rare case of PSA-negative metastasized prostate cancer to the stomach with serum CEA and CA19-9 elevation: a case report

Background

Metastatic cancer to the stomach is relatively rare. Prostate-specific antigen (PSA) is a reliable biomarker used in the screening and management of patients with prostate cancer. However, it is difficult to definitively diagnose a PSA-negative metastatic gastric tumor of prostate cancer because the cancer sometimes resembles primary gastric cancer in clinical images. It is also difficult to distinguish metastatic cancer from primary cancer even in the pathological examination of biopsy samples when the lesion is poorly differentiated adenocarcinoma. There is a possibility that the characteristics of the cancer are changed during treatment such as chemotherapy or radiation therapy. Therefore, careful consideration is required for surgical indication.

Case presentation

A 60-year-old male underwent radical prostatectomy and subsequent radiation therapy for advanced prostate cancer (pT3N1M0) 10 years previously, and hormone therapy was started for metachronous multiple bone metastasis 10 months before. Upper gastrointestinal endoscopy revealed an irregular depressed lesion with a convergence of folds at the greater curvature of the upper gastric body. Biopsy showed poorly differentiated adenocarcinoma that was negative for PSA upon immunohistochemistry. He had high serum carcinoembryonic antigen (CEA) (946.1 ng/ml) and carbohydrate antigen 19-9 (CA19-9) (465.1 U/ml) levels with no elevation of PSA (0.152 ng/ml). The tumor was diagnosed as primary gastric cancer based on the clinical imaging and pathological examination of the biopsy sample including the PSA staining. Based on the diagnosis, laparoscopic proximal gastrectomy with lymphadenectomy was performed. However, pathological examination of the resected specimen revealed poorly differentiated adenocarcinoma that was positive for other prostate markers such as androgen receptor. Thus, the patient was diagnosed with metastasized prostate cancer to the stomach.

Conclusions

We report a case of metastatic gastric cancer of prostate cancer 10 years after radical prostatectomy. In the present case, it was difficult to diagnose a metastatic gastric tumor of prostate cancer preoperatively, because of its resemblance to primary gastric cancer without PSA expression and no serum PSA elevation. Although a rare case entity, it is important to consider the possibility of a metastatic gastric tumor when the surgical indication is determined in cases with another co-existing cancer.

Gene amplification of YB-1 in castration-resistant prostate cancer in association with aberrant androgen receptor expression

Although Y‐box binding protein‐1 (YB‐1) is known to be overexpressed in prostate cancer, especially castration‐resistant prostate cancer (CRPC), the mechanism of its overexpression remains unclear. We aimed to elucidate the mechanism of YB‐1 overexpression in CRPC. Gene amplification in CRPC cells and tissues was examined by public database analysis, and digital PCR. The significance of YB‐1 amplification for the YB‐1/androgen receptor (AR) axis and prognosis was examined by public database analysis and immunohistochemistry. YB‐1 amplification was mainly observed in CRPC tissues by public database analysis and confirmed in CRPC cells and tissues by digital PCR. Expression of YB‐1 was increased in CRPC tissues compared with treatment‐naïve tissues. Furthermore, YB‐1 and phosphorylated YB‐1 levels were associated with AR and AR V7 expression levels. Finally, YB‐1 amplification was associated with poor outcomes in CRPC. Taken together, the present findings suggest that YB‐1 amplification contributes to progression to CRPC through regulation of AR and AR V7 expressions, and that YB‐1 is a promising therapeutic target in CRPC.

The role of adipocytokines and their receptors in bladder cancer: expression of adiponectin or leptin is an independent prognosticator

Adipocytokines such as leptin and adiponectin have functions in metabolism as well as the development and progression of various types of malignancies. However, little is known about their role in bladder cancer. In this study, we investigated whether leptin, adiponectin, and their receptors have an impact on bladder cancer outgrowth and the mechanisms involved. We performed immunohistochemistry for leptin, leptin receptor (Ob-R), adiponectin, and adiponectin receptors (AdipoR1, AdipoR2) in bladder cancer tissue microarrays. Wound healing assay and western blot were then performed in human bladder cancer lines. The positive rates (0 vs 1+/2+/3+) of Ob-R (P=0.004), adiponectin (P<0.001), AdipoR1 (P=0.016), and AdipoR2 (P<0.001) expression were significantly higher in bladder tumors than in benign urothelial tissues. Strong (3+) leptin expression tended to be present more often in tumors (10.2%; P=0.079) than in benign tissues (3.2%). Multivariate analysis revealed a lower risk of recurrence (hazard ratio [HR]=0.432; 95% confidence interval [CI]=0.198-0.942; P=0.034) in patients with an adiponectin-positive non-muscle-invasive tumor and a higher risk of progression (HR=5.148, 95% CI=1.190-22.273; P=0.028) in patients with a leptin-positive muscle-invasive tumor. Treatment of two bladder cancer cell lines with a synthetic adiponectin inhibited their migration and the expressions of phospho-NF-κB, NF-κB, snail, slug, Y-box-binding protein 1, and COX-2, whereas leptin showed reverse effects. Downregulation of adiponectin expression and upregulation of leptin expression were independent predictors for the recurrence of non-muscle-invasive bladder tumors and progression of muscle-invasive bladder tumors, respectively. In summary, synthetic adiponectin might exhibit antitumor activity against bladder cancer.

The SWI/SNF chromatin-remodeling complex status in renal cell carcinomas with sarcomatoid or rhabdoid features

The presence of sarcomatoid or rhabdoid features (which are associated with advanced disease and poor prognosis) is rarely observed in the subtypes of renal cell carcinoma (RCC). The SWI/SNF chromatin-remodeling complex, which is composed of evolutionarily conserved core subunits including SMARCB1/INI1 (SMARCB1), SMARCA4/BRG1 (SMARCA4), SMARCC1/BAF155 (SMARCC1), and SMARCC2/BAF170 (SMARCC2), can be regarded as the prototype of an epigenetic regulator of gene expression that is involved in tumor suppression. We analyzed the histological, immunohistochemical, and clinicopathological status in 72 cases of RCC with sarcomatoid or rhabdoid features, focusing on the expression status of the subunits of SWI/SNF chromatin-remodeling complex proteins. Cases with lost or reduced expression were defined as showing aberrant expression. The frequency of aberrant SMARCA4 immunoexpression of a sarcomatoid or rhabdoid component in clear cell RCC (ccRCC) (47/50, 94%) was significantly higher than that in non-ccRCC (4/9, 44%) (p < 0.001). In ccRCC without sarcomatoid or rhabdoid features, aberrant SMARCA4 immunoexpression was observed in 33 of 48 (67%) cases. Immunoreactivities for SMARCB1, SMARCA2, and SMARCC2 were retained in almost all subtypes of RCC. The patients with aberrant SMARCA4 expression in RCC with sarcomatoid or rhabdoid features achieved shorter progression-free survival compared with the patients with retained SMARCA4 expression (all subtypes of RCC, p = 0.0212; ccRCC, p = 0.0265). These results suggest that in ccRCC, aberrant SMARCA4 expression is one of the adverse prognostic factors or a high-grade malignant transforming factor. The evaluation of SMARCA4 immunoexpression may be a useful diagnostic tool to help distinguish ccRCC from non-ccRCC.

Programmed death ligand 1/indoleamine 2,3-dioxygenase 1 expression and tumor-infiltrating lymphocyte status in renal cell carcinoma with sarcomatoid changes and rhabdoid features

Renal cell carcinoma (RCC) with sarcomatoid changes and rhabdoid features has shown poor outcomes. Several immune checkpoint inhibitors including programmed cell death protein 1 (PD-1)/programmed death ligand-1 (PD-L1) inhibitors have been approved for the treatment of RCC. Combination therapy using PD-1/PD-L1 and indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors has also been used to treat various malignancies. However, little is known about IDO1 expression and therapeutic effects of the IDO1 inhibitor in RCC. Herein, we retrospectively analyzed the expression of PD-L1/IDO1 and examined its relationship with tumor-infiltrating lymphocyte (TIL) status and prognostic effect. We investigated the PD-L1, IDO1, CD3⁺, CD4⁺, and CD8⁺ immunoexpression status in 60 cases of sarcomatoid/rhabdoid RCC. The PD-L1 and IDO1 results were defined by the tumor proportion score. For the evaluation of TIL status, we counted the number of lymphocytes located in the tumor and averaged the numbers over five high-power fields for each case. The results revealed PD-L1 and IDO1 expression was observed more frequently in the sarcomatoid/rhabdoid component than in the nonsarcomatoid/nonrhabdoid component. The correlation between PD-L1 and IDO1 expression was significant (P = 0.0076). PD-L1 expression and coexpression of PD-L1 and IDO1 were correlated with a high density of CD3⁺, CD4⁺, and CD8⁺ T cells. There was no significant difference in overall survival among the patients with PD-L1 and/or IDO1 expression, but PD-L1 expression and coexpression were related to poor progression-free survival. Our results suggest that combination therapy using the PD-1/PD-L1 inhibitor and IDO1 inhibitor may be effective for treating sarcomatoid/rhabdoid RCC.

Automated approach for estimation of grade groups for prostate cancer based on histological image feature analysis

BACKGROUND

There is a low reproducibility of the Gleason scores that determine the grade group of prostate cancer given the intra- and interobserver variability among pathologists. This study aimed to develop an automated approach for estimating prostate cancer grade groups based on features obtained from histological image analysis.

METHODS

Fifty-nine patients who underwent radical prostatectomy were selected under the approval of the institutional review board of our university hospital. For estimation, we followed the grade group criteria provided by the International Society of Urological Pathology in 2014. One hundred eight specimen slides obtained from the patients were digitized to extract 110 regions of interest (ROI) from hematoxylin and eosin-stained histological images using a digital whole slide scanner at ×20 magnification with a pixel size of 0.4 μm. Each color pixel value in the ROI was decomposed into six intensities corresponding to the RGB (red, green, and blue) and HSV (hue, saturation, and value) color models. Image features were extracted by histological image analysis, obtaining 54 features from the ROI based on histogram and texture analyses in the six types of decomposed histological images. Then, 40 representative features were selected from the 324 histological image features based on statistically significant differences (P < .05) between the mean image feature values for high (≥3, Gleason score ≥4 + 3) and low (≤2, Gleason score ≤3 + 4) grade groups. The relationship between grade groups and the most representative image feature (ie, complexity) was approximated using regression to estimate real-number grade groups defined by continuous numerical grading. Finally, the grade groups were expressed as the conventional grade groups (ie, integers from 1 to 5) using a piecewise step function.

RESULTS

The grade groups were correctly estimated by the proposed approach without errors on training (70 ROIs) and validation (40 ROIs) data.

CONCLUSIONS

Our results suggest that the proposed approach may support pathologists during the evaluation of grade groups for prostate cancer, thus mitigating intra- and interobserver variability.

Contractile elements and their sympathetic regulations in the pig urinary bladder: a species and regional comparative study

Contractile behaviour of the urinary bladder and its sympathetic inhibition during storage phases are not well understood. Here, we explore muscularis mucosae (MM) as a predominant mucosal contractile element and the capability of sympathetic nerves to relax detrusor smooth muscle (DSM) or MM. Distribution of α-smooth muscle actin (α-SMA)-immunoreactive cells was compared in pig, human, guinea pig, rat and mouse bladders by immunohistochemistry, while contractility of the bladder mucosa was compared in these species by isometric tension recordings. In pig, human and guinea pig bladders, DSM and MM located in the lamina propria expressed α-SMA immunoreactivity, while both rat and mouse bladders lacked a MM. Consistent with this presence or absence of MM, bladder mucosa of pig, human and guinea pig but not rat and mouse developed spontaneous phasic contractions (SPCs). Distribution of tyrosine hydroxylase (TH)-immunoreactive sympathetic nerve fibres was compared in pig DSM, MM, trigone and urethra, as were their sympathetic nerve-evoked contractile/relaxing responses examined. In pig DSM or MM, where TH-immunoreactive sympathetic fibres exclusively projected to the vasculature, sympathetic relaxations were difficult to demonstrate. In contrast, sympathetic contractions were invariably evoked in pig trigone and urethra where the smooth muscle cells receive TH-immunoreactive sympathetic innervations. Thus, SPCs of bladder mucosa appear to predominantly arise from the MM displaying species differences. Despite the currently accepted concept of sympathetic nerve-mediated DSM relaxation during the storage phase, it is unlikely that neurally released noradrenaline acts on β-adrenoceptors to relax either DSM or MM due to the anatomical lack of sympathetic innervation.

Papillary renal cell carcinoma with massive hematoma mimicking hemangioma

It is extremely rare that papillary renal cell carcinoma has a massive hemorrhage. We report a case of papillary renal cell carcinoma with a massive hemorrhage which showed hemangioma-like imaging findings such as a globular discontinuous enhancement on the corticomedullary phase with a gradual centripetal fill-in pattern on the excretory phase on computed tomography and heterogeneously hyperintensity on T2-weighted magnetic resonance imaging. We also discuss a plausible mechanism explaining such imaging findings, with reference to pathological findings.

Clinicopathological Significance and Antitumor Effect of MPHOSPH1 in Testicular Germ Cell Tumor

MPHOSPH1, which is one of the kinesin superfamily proteins, has been reported to play an essential role in the carcinogenesis and progression of several kinds of cancers. MPHOSPH1 has also been suggested to be involved in STAT3 phosphorylation in hepatocellular carcinoma. However, the biological behavior of MPHOSPH1 in testicular germ cell tumors (TGCTs) is unclear at present. The purposes of this study were to investigate the correlation between the expression of MPHOSPH1 and clinicopathological factors and to examine the efficacy of MPHOSPH1 target therapy in TGCTs. We investigated 75 formalin-fixed paraffin-embedded TGCT samples, containing a total of 86 germ cell tumor components, by immunohistochemistry and 12 frozen samples by Western blotting. Moreover, we carried out in vitro studies to clarify the antitumor effect of MPHOSPH1 knockdown in embryonal carcinoma cell lines, NEC8 and NEC14, using small interference RNA (siRNA). A significantly high expression of MPHOSPH1 was recognized in embryonal carcinoma and yolk sac tumor components compared to the seminoma component (p<0.001, respectively). Clinically, non-seminoma cases are known to have worse prognosis than pure-seminoma cases. Interestingly, high MPHOSPH1 expression was associated with distant metastasis (p=0.001), and thus with advanced-stage disease in this study. High expression of MPHOSPH1 interacted with high expression of phosphorylated STAT3 (p=0.01). The in vitro experiments demonstrated that MPHOSPH1 interruption by siRNA resulted in a significant reduction of cell migration, invasion, proliferation and colony formation in both embryonal carcinoma cell lines (p<0.001, respectively). In conclusion, MPHOSPH1 may be a potential treatment option for TGCTs, and its expression may be a novel biomarker of poor prognosis.

Metyrapone-responsive ectopic ACTH-secreting pheochromocytoma with a vicious cycle via a glucocorticoid-driven positive-feedback mechanism

In ectopic ACTH-secreting pheochromocytoma, combined ACTH-driven hypercortisolemia and hypercatecholaminemia are serious conditions, which can be fatal if not diagnosed and managed appropriately, especially when glucocorticoid-driven positive feedback is suggested with a high ACTH/cortisol ratio. A 46-year-old man presented with headache, rapid weight loss, hyperhidrosis, severe hypertension and hyperglycemia without typical Cushingoid appearance. Endocrinological examinations demonstrated elevated plasma and urine catecholamines, serum cortisol and plasma ACTH. Moreover, his ACTH/cortisol ratio and catecholamine levels were extremely high, suggesting catecholamine-dominant ACTH-secreting pheochromocytoma. Computed tomography revealed a large right adrenal tumor. ¹⁸F-FDG positron emission tomography showed uptake in the area of the adrenal tumor, while ¹²³I-metaiodobenzylguanidine scintigraphy showed no accumulation. His plasma ACTH level paradoxically became elevated after a dexamethasone suppression test. After metyrapone administration, not only serum cortisol but also plasma ACTH levels were exponentially decreased almost in parallel, suggesting a glucocorticoid-driven positive-feedback regulation in this rapidly exacerbated ectopic ACTH-producing pheochromocytoma. Interestingly enough, plasma catecholamine levels were also decreased by metyrapone, although they remained extremely high. He became severely dehydrated due to hypoadrenalism requiring hydrocortisone supplementation. His clinical signs and symptoms were improved, and right adrenalectomy was performed uneventfully, resulting in complete remission of pheochromocytoma and Cushing's syndrome. A glucocorticoid-driven positive-feedback regulation in this ectopic ACTH-secreting pheochromocytoma created a vicious cycle with rapid exacerbation of both hypercortisolemia and hypercatecholaminemia with extremely elevated plasma ACTH level. Metyrapone was clinically effective to stop this vicious cycle; nonetheless, great care must be taken to avoid hypoadrenalism especially when hypercatecholaminemia remained.

[Impact of 131I SPECT/CT on the management of differentiated thyroid carcinoma outpatients with radioablation]

OBJECTIVE

The purpose of this study was to comparatively assess the diagnostic accuracy between 131I SPECT/CT and 131I whole-body scintigraphy (WBS) in differentiated thyroid carcinoma outpatients following radioablation.

METHODS

a retrospective cohort study was performed in eleven patients with differentiated thyroid carcinoma (fourteen studies), who underwent both 131I WBS and 131I SPECT/CT, 7-10 days after administration of 1,110 MBq of 131I for radioablation, following a total thyroidectomy. A head and neck surgeon and two nuclear medicine specialists first interpreted the WBS images, followed by SPECT/CT images.

RESULTS

SPECT/CT led to accurate revisions of the first diagnoses in 13 of 24 cervical foci of 131I uptake on WBS. Out of the 5 distant lesions, which were diagnosed as metastases by WBS alone, 5 (100%) were found out to be benign lesions by SPECT/CT. Thus, WBS was prone to be false-positive both in detecting cervical node metastases (13/28, 46.4%) and distant metastases (5/17, 29.4%). Eventually, SPECT/CT after 131I radioablation altered postoperative patients' management in 42.8% of patients with thyroid carcinoma by upstaging or down-staging their disease.

CONCLUSION

SPECT/CT after 131I radioablation for differentiated thyroid cancer patients determines more accurately cervical lymph node metastasis, thyroid remnants and distant metastasis than does WBS alone. Both WBS and SPECT/CT after 131I radioablation are highly recommended for appropriate management of differentiated thyroid cancer patients who have undergone a total thyroidectomy.

[Silent myocardial ischemia and exercise-induced arrhythmia detected by the exercise test in the total health promotion plan (THP)]

We investigated the prevalence and characteristics of ischemic heart disease especially silent myocardial ischemia (SMI) and arrhythmia in need of careful observation in the exercise stress tests in the Total Health Promotion Plan (THP), which was conducted between 1994-96 for the purpose of measuring cardiopulmonary function. All workers (n = 4,918, 4,426 males) aged 18-60 yr old in an occupational field were studied. Exercise tests with an ergometer were performed by the LOPS protocol, in which the maximal workload was set up as a presumed 70-80% maximal oxygen intake, or STEP (original multistage protocol). ECG changes were evaluated with a CC5 lead. Two hundred and fifteen people refused the study because of a common cold, lumbago and so on. Of 4,703 subjects, 17 with abnormal rest ECG and 19 with probable anginal pain were excluded from the exercise tests. Of 4,667 who underwent the exercise test, 37 (0.79%) had ischemic ECG change, and 155 (3.32%) had striking arrhythmia. These 228 subjects then did a treadmill exercise test with Bruce protocol. Twenty-two (0.47% of 4,703) showed positive ECG change, 9 (0.19%) of 22 had abnormal findings on a 201Tl scan. 8 (0.17%) were diagnosed as SMI (Cohn I), in which the prevalence of hypertension, hyperlipidemia, diabetes mellitus, smoker and positive familial history of ischemic heart disease was greater than that of all subjects. In a 15-30 month follow up, none has developed cardiac accidents. Exercise-induced arrhythmia was detected in 11 (0.23%) subjects. Four were non-sustained ventricular tachycardia without any organic disease, 4 were ventricular arrhythmia based on cardiomyopathy detected by echocardiography, 2 were atrial fibrillation and another was WPW syndrome. It is therefore likely that the ergometer exercise test in THP was effective in preventing sudden death caused by ischemic heart disease or striking arrhythmia.

[Influence of the radioactive strontium (89Sr) using for nuclear medical radiation therapy upon radioactive draining-water system]

PURPOSE

Strontium-89 chloride (89Sr) is a new radiopharmaceutical that provides effective pain relief for metastatic bone lesions, and is expected to be available soon in the palliative management for metastatic bone pain in Japan. Because of relatively long physical half life (50.5 days), 89Sr may affect to the radioactive draining-water system by exceeding the limits of activity concentration for radioactive drain. In this article, the influence of 89Sr use on the radioactive drainage system was simulated.

METHODS

The standard tank capacity of drainage and draining frequency was determined from the results of questionnaire carried out for the nationwide medical and research institutes where radioisotope treatment are performed. On the assumption that 89Sr of 148 MBq for one therapy was used twice a week and several common radionuclides were used as the same activity as used at Chiba Cancer Center, the influence of 89Sr was estimated. The calculation was performed using the activity contamination ration into the draining-water system of each radionuclide of 0.01, which was legally determined.

RESULTS

The simulation revealed that the sum of the contamination ratios of individual radionuclides exceeded a legal value of 1.0 in standard drainage with the capacity of 5 m3 and 10 m3 and draining frequency of 7 times per year. The actual contamination ratios of common radiopharmaceuticals measured at Chiba Cancer Center ranged from 1/100 to 1/1000 of the legal values.

CONCLUSION

It is necessary that the legal value of activity contamination ratios into the draining-water system should be reassessed before starting 89Sr therapy.

[Quantitative evaluation for scatter and attenuation correction in 99mTc SPECT--multicenter cooperation phantom study]

A multicenter cooperation phantom study was conducted to evaluate the accuracy of a triple energy window scatter correction technique in combination with various attenuation correction methods for 99mTc single photon emission computed tomography (SPECT) imaging. Six centers participated in this research and the data obtained with seven SPECT instruments were analyzed. The phantom used in the experiment was a 20 x 10 cm cylinder filled with homogeneous 99mTc solution, containing two kinds of cold spots (cold rod phantoms). One had a water-filled cylinder 5.5 cm in diameter positioned 2.5 cm from the center. The other contained 6 water-filled cylinders of various sizes. Contrasts of cold regions were in the range from 74% to 120% (true 100%). Another phantom had the shape of a pie-chart divided into six chambers symmetrically positioned in a cylinder 20 cm in diameter and 10 cm in height. Each chamber had volume of 480 ml and contained homogeneous 99mTc solution of different concentrations. This phantom was used to test for linearity between the radio activity concentration and reconstructed count density (linearity phantom). The intercept of the regression line obtained from the linearity phantom was 8.4 kBq ml-1 without scatter correction and -6.8 kBq ml-1 with scatter correction. Contrast was in the range from 78% to 132% (true 100%). The mean relative error for the measured activity concentration was 4.9% +/- 3.5% (mean +/- sd).

[Investigation of radiation safety management of nuclear medicine facilities in Japan; contamination of radioactivity in the draining-water system. A Working Group of Japanese Society of Nuclear Medicine for the Guidelines of Nuclear Medicine Therapy]

Radiation safety management condition in Japanese nuclear medicine facilities were investigated by the questionnaire method. The first questionnaire was asked in all Japanese 1,401 Nuclear Medicine facilities. Answers from 624 institutes (44.5%) were received and analyzed. The radiation-safety management in nuclear medicine institutes was considered to be very well performed everyday. Opinion for the present legal control of nuclear medicine institutes was that the regulation in Japan was too strict for the clinical use of radionuclides. The current regulation is based on the assumption that 1% of all radioactivity used in nuclear medicine institutes contaminates into the draining-water system. The second questionnaire detailing the contamination of radioactivity in the draining-water system was sent to 128 institutes, and 64 answers were received. Of them, 42 institutes were considered to be enough to evaluate the contamination of radioactivity in the draining-water system. There was no difference between 624 institutes answered to the first questionnaire and 42 institutes, where the radioactivity in the draining-water system was measured, in the distribution of the institute size, draining-water system equipment and the radioactivity measuring method, and these 42 institutes seemed to be representative of Japanese nuclear medicine institutes. Contamination rate of radioactivity into the draining system was calculated by the value of radioactivity in the collecting tank divided by the amount of radionuclides used daily in each institute. The institutes were divided into two categories on the basis of nuclear medicine practice pattern; type A: in-vivo use only and type B: both in-vivo and in-vitro use. The contamination rate in 27 type A institutes did not exceed 0.01%, whereas in 15 type B institutes the contamination rate distributed widely from undetectable to above 1%. These results indicated that the present regulation for the draining-water system, which assumed that 1% of all radioactivity used in nuclear medicine institutes contaminated into draining-water system, should be reconsidered in nuclear medicine facilities where radionuclides are used only in in-vivo studies.

Effects of low-intensity aerobic training on the high-density lipoprotein cholesterol concentration in healthy elderly subjects

The concentration of high-density lipoprotein cholesterol (HDL-C) is inversely correlated with the risk of coronary heart disease. The effects of low-intensity aerobic training on serum HDL-C and other lipoprotein concentrations were examined in healthy elderly subjects. The subjects were randomly assigned to two groups matched for sex, age, height, and weight. The training group (n = 20, 10 men and 10 women aged 67 +/- 4 years) participated in a supervised physical exercise regimen using a bicycle ergometer at an intensity of 50% estimated maximal oxygen consumption (VO2max) for 60 minutes two to four times per week for 5 months. In contrast, the control group (n = 20, 10 men and 10 women aged 68 +/- 4 years) did not perform any particular physical training. The training protocol resulted in significant increases in the VO2max (P < .05), HDL-C, HDL2-C, and HDL2-C/HDL3-C ratio (P < .01). The change in HDL2-C (r = .57, P < .01) and HDL2-C/HDL3-C (r = .63, P < .01) was positively associated with an increase in the total exercise duration per week. In addition, the total weekly exercise duration also showed a significant positive relationship with HDL-C (r = .75, P < .01), HDL2-C (r = .81, P < .01), and HDL2-C/HDL3-C (r = .71, P < .01) after the training period. The changes in body weight and the VO2max were not significantly correlated with any lipid parameters. Low-intensity aerobic training may improve the profile of HDL-C and its subfractions in healthy elderly subjects. Also, the total exercise duration may be an important factor for improving HDL-C and HDL2-C in elderly subjects.

67Ga planar imaging with a low-energy collimator and scatter correction using the triple energy window method

To improve the spatial resolution and contrast of 67Ga planar imaging, we used a low-energy collimator and two lower-energy windows with a triple-energy-window (TEW) scatter compensation method. The spatial resolution is better than with a medium-energy collimator, and the TEW method can correct for scattered photons and reduce the background counts. In a phantom study and a clinical study involving 44 patients, the images obtained by the proposed method were compared with the images obtained with a medium-energy collimator and three energy windows without scatter compensation (the conventional method). The spatial resolution and the counts were measured. Two nuclear medicine physicians interpreted the images and clinical usefulness was evaluated. The spatial resolution and contrast were improved by our proposed method. It enabled the detection of lesions in five locations in the clinical study. The counts were reduced but misreadings were not seen. We conclude that our proposed method shows a clinical advantage over the conventional method. It can be used easily and quickly with commercially available equipment and is useful in clinical practice.

Blood pressure lowering effect of low intensity aerobic training in elderly hypertensive patients

PURPOSE

The purpose of this investigation was to determine the effect of 9 months of low intensity aerobic training on blood pressure in elderly hypertensive patients who were receiving antihypertensive medication.

METHODS

The training group (N = 13; mean age 75.4 +/- 5.4 yr) agreed to take part in physical training using a treadmill with an exercise intensity at the blood lactate threshold (LT) for 30 min three to six times a week for 9 months. The rest (N = 13; mean age 73.1 +/- 4.2 yr) served as controls.

RESULTS

The resting systolic (-15 +/- 8 mm Hg), mean (-11 +/- 6 mm Hg), and diastolic blood pressures (-9 +/- 9 mm Hg) decreased significantly after 3 months of training and the blood pressure of all participants stabilized at a significantly lower level by the end of the study (9 months) in the training group, whereas no significant changes in blood pressure were found in the control group. Both the pretraining systolic and diastolic blood pressure of those recruited patients negatively correlated with those changes after the training (SBP: P < 0.01; DBP: P < 0.05, respectively). After 1 month of detraining in five patients, the blood pressure levels were similar to those in the pretraining state. The LT increased significantly in the training group (P < 0.01).

CONCLUSION

In conclusion, an additional antihypertensive effect of mild aerobic training at the LT was confirmed in elderly patients receiving antihypertensive medication. The cessation of such training in five patients, however, resulted in a relatively rapid return to pretraining levels within a month.

[Frameless registration for chest SPECT and X-ray CT image by volume matching]

Image registration of functional (SPECT) and morphological (X-ray CT/MRI) images has been studied in order to improve the accuracy and the quality of the image diagnosis. This paper describes a new registration method for chest SPECT and X-ray CT images. Presented method is a frameless and automatic registration method which calculates a transformation matrix between two coordinate systems of image data by an optimization method. This registration method uses similar physical characteristics of X-ray CT and transmission CT image. The three-dimensional overlap of the body region is used for image matching. Precision evaluation and visual image evaluation were conducted. The result of the precision evaluation with a phantom and clinical data suggested the clinically acceptable robustness in registration procedure. Visual evaluation of registered images confirmed the usefulness of this method in clinical applications.

Absent myocardial accumulation of two different radioiodinated pentadecanoic acids

This article presents two cases with preserved myocardial 201Tl uptake and absent uptake of two kinds of radioiodinated fatty acids: iodine-123-labeled 15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) and iodine-123-labeled 15-(p-iodophenyl)-9-(R,S)-methylpentadecanoic acid (9MPA). Although coronary angiography showed no stenotic lesion and left ventriculography revealed no wall motion abnormality, no myocardial uptake of BMIPP and 9MPA was observed in the first case. In the second case, no myocardial accumulation was recognized even in the initial phase of dynamic SPECT acquired soon after the injection of 9MPA. The results suggest that the non-visualized myocardium was not specific for BMIPP imaging and that rather than the early back diffusion of the tracers from the myocardium, abnormality of the myocardial cell membrane was a possible mechanism accounting for the phenomenon.

[Quantitative measurement of cerebral blood flow by the microsphere model with super-early 123I-IMP brain SPECT]

Cerebral blood flow (CBF) was quantitatively measured in 6 healthy young volunteers based on "super-early" acquisition of N-isopropyl-p-[123I]iodoamphetamine (IMP) brain SPECT obtained 4-6 min after IMP injection with a three-head rotating gamma camera and the microsphere (MS) model. The ratio of radioactivity (count/pixel/min) in the conventional early SPECT image (taken 25-55 min after IMP injection) to that in the "super-early" image for each brain region negatively correlated with regional CBF value obtained with the "super-early" MS method. This indicates that wash-out of IMP from the regions with higher CBF is faster than that from the regions with lower CBF and that CBF values are underestimated with the conventional MS method in regions with higher CBF. Regional CBF was quantitatively measured with the "super-early" MS method and the ARG method, a recently developed method based on two-compartment model. The mean cortical CBF was 52.5 +/- 7.0 (ml/100 g/min, mean +/- SD) with the "super-early" MS method and 47.5 +/- 3.3 with the ARG method. The CBF values obtained with the "super-early" MS method agreed with those previously reported with positron emission tomography. Since the MS method is theoretically the simplest model, the "super-early" MS method can be applied various disorders of the central nervous system where the behavior of IMP is not fully understood.

Thallium-201 single-photon emission tomography in the treatment follow-up of nasopharyngeal carcinoma

In order to assess the usefulness of thallium-201 single-photon emission tomography (SPET) in the treatment follow-up of nasopharyngeal carcinoma (NPC), a total of 75 201T1 SPET studies were performed in 18 patients with histologically proven NPC. The findings were compared with those of magnetic resonance imaging (MRI) before and after therapy. Four patients received radiotherapy alone while the other 14 received concurrent chemo-radiotherapy. Treatment response was classified as complete (CR) or partial (PR) based on the findings of MRI and 201T1 SPET. Intense 201T1 uptake by the tumour was seen in all 18 patients before treatment. After treatment, MRI showed seven CRs and 11 PRs, whereas 201T1 SPET showed 13 CRs and five PRs. In 12 patients, the results of 201T1 SPET were in agreement with those of MRI. In six patients MRI showed PR but 201T1 showed CR. Follow-up (mean 10.6 months) MRI and 201T1 SPET studies of these six patients revealed that tumour gradually decreased and finally vanished in three patients. This preliminary study indicates that 201T1 SPET has potential in the assessment of early response to treatment of patients with NPC when compared with MRI.

Quantitative evaluation in tumor SPECT and the effect of tumor size: fundamental study with phantom

An experimental study with phantoms was performed in order to evaluate the effect of the tumor volume on the quantitative estimation in tumor SPECT. The ratio of mean count/pixel in the phantom to that of the background (T/N ratio) was well correlated with the size of the phantom: even when the concentration of the Tc-99m O-4 solution of globular phantoms with diameters of 29, 37 and 46 mm was constant, the greater the size of the phantom, the higher was the T/N ratio. This study showed that we should understand that the T/N ratio was certainly affected by the reduction of the tumor size itself whenever we evaluate treatment-response or assess tumor viability after treatment by reference to the T/N ratio.

The effect of steroid on thallium-201 uptake by malignant gliomas

In order to assess the effect of steroid on thallium-201 uptake by glioma, 201Tl single-photon emission tomography was performed before and after steroid administration in four patients with recurrent malignant glioma. After steroid administration the 201Tl index, expressed as the ratio of 201Tl uptake in the tumour to that in the contralateral cerebral hemisphere, was 0.77+/-0.11 of the value before steroid (mean+/-SD: P<0.05 by paired t test). The 201Tl index has been used as a possible indicator for the differentiation of malignant gliomas from relatively benign tumours or radiation necrosis. The present results indicate that the effect of steroid has to be taken into account when semi-quantitative analysis, e.g. by means of the 201Tl index, is used in patients with brain tumours.

Protein tyrosine kinase inhibitors promote amylase secretion and inhibit ornithine decarboxylase induction in sialagogue-stimulated rat parotid explants

Three sialagogues, isoproterenol (IPR), carbachol, and methoxamine, caused induction of ornithine decarboxylase (ODC) in cultured rat parotid explants. All the protein tyrosine kinase inhibitors tested suppressed this ODC induction but enhanced sialagogue-dependent amylase secretion. Sodium orthovanadate showed the reverse effects as the kinase inhibitors. Immunoblot analysis with anti-phosphotyrosine antibody revealed that herbimycin A depresses IPR-stimulated tyrosine phosphorylation of parotid proteins. Herbimycin A did not affect the IPR- or dibutyryl cAMP-induced surge of the parotid cAMP level but inhibited these agonist-dependent ODC inductions. These results suggest that sialagogue-induced ODC induction and amylase secretion are mediated by different signal transduction pathways and that protein tyrosine kinase participates in IPR-dependent ODC induction and amylase secretion in the process subsequent to the cAMP surge.

The activity and expression of thymidine phosphorylase in human solid tumours

Thymidine phosphorylase (dThdPase) is identical to platelet-derived endothelial cell growth factor (PD-ECGF) and has angiogenic activity. Since dThdPase seems to have an important role in angiogenesis of tumours, we measured the activity and expression of dThdPase in various tumours and the adjacent non-neoplastic tissues. We assayed dThdPase activity by spectrophotometric means, and the expression of dThdPase was examined by immunoblotting and by immunohistochemical staining using a monoclonal antibody against dThdPase. In the oesophagus, stomach, colorectum, pancreas, and lung, dThdPase activity in carcinomas was significantly higher (P < 0.05) than that in the adjacent non-neoplastic tissues. The expression level of dThdPase detected by immunoblotting correlated well with the activity of dThdPase. In the oesophagus, stomach, colorectum, gall bladder, pancreas and lung, the proportion of dThdPase-positive tumours was significantly higher (P < 0.05 or 0.01) than that of the dThdPase-positive adjacent normal tissues. In oesophageal, gastric colorectal and lung carcinomas, the proportion of dThdPase positivity in advanced carcinomas was significantly higher (P < 0.01) than that in early carcinomas. Tumour-infiltrative macrophages or lymphocytes in the lymph node, alveolar macrophages and Kupffer cells expressed high levels of dThdPase. The results indicate that dThdPase activity and expression level in many tumours are higher than those in the adjacent non-neoplastic tissues, and that dThdPase may have an important role in the proliferation of these solid tumours.

Quantifying brain tumor blood flow by the microsphere model with N-isopropyl-p-[123I]iodoamphetamine super-early SPECT

Regional cerebral blood flow was quantitatively measured in 6 patients with brain tumor by the microsphere model with N-isopropyl-p-[123I]iodoamphetamine (IMP) "super-early" single photon emission computed tomography (SPECT) images obtained 4-6 min after IMP injection with a three-head rotating gamma camera. The ratio of radioactivities (counts/pixel/min) in the "early" SPECT images (taken 25-55 min after IMP injection) to the "super-early" images of the brain tumors was 1.47 +/- 0.13 (mean +/- SD, n = 6), which was significantly lower than the ratio in the normal cerebral cortices (1.93 +/- 0.25) (p < 0.01). This indicates faster clearance of IMP from the tumor tissue than that from the normal brain tissue. Blood flow values for the brain tumors obtained by the microsphere model based on the "super-early" SPECT images were 39.3 +/- 12.4 ml/100 g/ min, which was similar to the blood flow values for normal gray matter and in agreement with previous studies with positron emission tomography.

[A study on thallium-201 SPECT in brain metastases of lung cancer: with special reference to tumor size and tumor to normal brain thallium uptake ratio]

Thallium-201 brain SPECT was performed on 20 patients with brain metastases of lung cancer using a three-head rotating gamma camera and the effect of tumor size on tumor detectability and tumor to normal brain thallium uptake ratio (T/N ratio) was studied. Among 71 metastatic lesions, only 9 (22.5%) of 40 lesions of 13 mm diameter or below and 31 (100%) of 31 lesions of 14 mm diameter or above could be detected in this study. There was a significant correlation between T/N ratio and tumor size (r = 0.75, p < 0.001). The greater the metastatic lesion, the higher the T/N ratio. Even among the tumors in a single patient with multiple brain metastases, there was a significant linear correlation between tumor size and T/N ratio (r = 0.96, p < 0.01). In this patient, T/N ratio varied by the tumor size and these differences in T/N ratios were thought to be based on the partial volume effect. However, T/N.d which was a parameter corrected by tumor diameter (d) showed a constant value regardless of tumor size. The present results showed that T/N ratio, which was usually believed to quantitate the malignancy grade of brain tumor, was affected by tumor size and that more accurate parameter could be obtained by the correction of T/N ratio by tumor size.