Impact of Tumor Grade Distribution on Genetic Alterations in Clear Cell Renal Cell Carcinoma and Prostate Cancer.

BACKGROUND/AIM: A genomic analysis based on next-generation sequencing is important for deciding cancer treatment strategies. Cancer tissue sometimes displays intratumor heterogeneity and a pathologic specimen may contain more than two tumor grades. Although tumor grades are very important for the cancer prognosis, the impact of higher tumor grade distribution in a specimen used for a genomic analysis is unknown. PATIENTS AND METHODS: We retrospectively analyzed the data of 61 clear cell carcinoma and 46 prostate cancer patients that were diagnosed between December 2018 and August 2022 using the GeneRead Human Comprehensive Cancer Panel or SureSelect PrePool custom Tier2. Genome annotation and curation were performed using the GenomeJack software. RESULTS: Tumor mutation burden (TMB) was increased in proportion to the higher tumor grade distribution in grade 2 clear cell renal cell carcinoma (ccRCC). In PC, Grade Group 3/4 specimens that included an increased distribution of Gleason pattern 4 had more frequent gene mutations. CONCLUSION: Our results suggest the importance of selecting the maximum distribution of higher tumor grade areas to obtain results on the precise gene alterations for genomics-focused treatments.

A Case Report of Syphilis That Was Difficult to Distinguish From Penile Carcinoma.

A 43-year-old man presented with penile induration and lymphadenopathy. Computed tomography revealed multiple enlarged lymph nodes (LNs). Penile cancer was suspected, and a LN biopsy was performed. Histopathological examination revealed inflammation and fibrosis, with no findings indicating malignancy. Serological examination confirmed syphilis and treatment with amoxicillin was initiated. Thereafter, swelling in the LNs improved quickly. Penile cancer is usually suspected in the presence of penile induration. However, syphilis can also present with similar symptoms. To distinguish between syphilis and penile cancer, the patient's history, results of physical examination, and presence of tumor and infectious markers should be considered.

Perilesional Targeted Biopsy Combined with MRI-TRUS Image Fusion-Guided Targeted Prostate Biopsy: An Analysis According to PI-RADS Scores.

A prostate-targeted biopsy (TB) core is usually collected from a site where magnetic resonance imaging (MRI) indicates possible cancer. However, the extent of the lesion is difficult to accurately predict using MRI or TB alone. Therefore, we performed several biopsies around the TB site (perilesional [p] TB) and analyzed the association between the positive cores obtained using TB and pTB and the Prostate Imaging Reporting and Data System (PI-RADS) scores. This retrospective study included patients who underwent prostate biopsies. The extent of pTB was defined as the area within 10 mm of a TB site. A total of 162 eligible patients were enrolled. Prostate cancer (PCa) was diagnosed in 75.2% of patients undergoing TB, with a positivity rate of 50.7% for a PI-RADS score of 3, 95.8% for a PI-RADS score of 4, and 100% for a PI-RADS score of 5. Patients diagnosed with PCa according to both TB and pTB had significantly higher positivity rates for PI-RADS scores of 4 and 5 than for a PI-RADS score of 3 (p < 0.0001 and p = 0.0009, respectively). Additional pTB may be performed in patients with PI-RADS ≥ 4 regions of interest for assessing PCa malignancy.

Low Body Mass Index as a Predictive Factor for Postoperative Infectious Complications after Ureterorenoscopic Lithotripsy.

Background and Objectives: In this study, we aimed to evaluate predictive factors of postoperative fever (POF) after ureterorenoscopic lithotripsy (URSL). Materials and Methods: A total of 594 consecutive patients who underwent URSL for urinary stone disease at Gifu Municipal Hospital and Chuno Kosei Hospital between April 2016 and January 2021 were enrolled in this study. In all patients, antibiotics were routinely administered intraoperatively and the next day after surgery. We used rigid and/or flexible ureterorenoscopes depending on the stone location for URSL. Stones were fragmented using a holmium: YAG laser. The fragments of the stone were manually removed as much as possible using a stone basket catheter. A ureteral stent was placed at the end of the surgery in all cases. Results: The median age and body mass index (BMI) in all patients were 62 years and 23.8 kg/m2, respectively. The median operation duration was 52 min. The most common URSL-related complication was POF in 28 (4.7%) patients. In these patients, the rates of antibiotic administration and ureteral stent insertion before surgery were significantly higher than in those without POF. In multivariate analysis, BMI was associated with POF after URSL. There were no significant differences in predicting POF after surgery in patients who had bacteriuria or received antibiotics before surgery. Conclusions: A low BMI was significantly associated with POF after URS or URSL.

The accuracy of prostate cancer diagnosis in biopsy-naive patients using combined magnetic resonance imaging and transrectal ultrasound fusion-targeted prostate biopsy.

BACKGROUND: This study aimed to estimate whether multiparametric magnetic resonance imaging (mpMRI)-transrectal ultrasound (TRUS) fusion biopsy (FUS-TB) increases the detection rates of clinically significant prostate cancer (csPCa) compared with TRUS-guided systematic biopsy (TRUS-GB). METHODS: This retrospective study focused on patients who underwent mpMRI before prostate biopsy (PB) with Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) scores ≥3 and prostate-specific antigen (PSA) level between 2.5 and 20 ng/mL. Before FUS-TB, the biopsy needle position was checked virtually using three-dimensional mapping. After confirming the position of the target within the prostate, biopsy needle was inserted and PB was performed. Suspicious lesions were generally targeted with 2 to 4 cores. Subsequently, 10-12 cores were biopsied for TRUS-GB. The primary endpoint was the PCa detection rate (PCDR) for patients with PCa who underwent combined FUS-TB and TRUS-GB. RESULTS: According to PI-RADS v2, 76.7% of the patients with PI-RADS v2 score ≥3 were diagnosed with PCa. The PCDRs in patients with PI-RADS v2 score of 4 or 5 were significantly higher than those in patients with PI-RADS v2 score of 3 (3 vs. 4, P<0.001; 3 vs. 5, P<0.001; 4 vs. 5, P=0.073). According to PCDR, the detection rates of PCa and csPCa in the FUS-TB were significantly higher than that in the TRUS-GB. CONCLUSIONS: Following detection of suspicious tumor lesions on mpMRI, FUS-TB use detects a higher number of PCa cases compared with TRUS-GB.

The resonance® metallic ureteral stent in the treatment of malignant ureteral obstruction: a prospective observational study.

BACKGROUND: To study the outcomes and experiences of using metallic stents in treating patients with malignant ureteral obstruction (MUO), we examined the effects of metallic ureteral stenting using the Cook Resonance® stent in the treatment of MUO. METHODS: All patients who had a Resonance metallic stent inserted between April 2015 and March 2018 at one of multiple facilities were prospectively observed with a 1-year follow-up. The primary outcome was the patency rate of the metallic ureteral stent. The secondary outcomes included the complications (e.g., infection and fever). RESULTS: Although stent insertion was attempted in 50 patients, the stent could not be inserted as a ureteral stent in three patients due to severe ureteral stricture, and one ureteral cancer patient was excluded from the analysis. The remaining 46 patients' median age was 67 years (range 28-85 years) (16 males, 30 females). Twenty-four patients died during the study; their median survival time was 226 days. The median follow-up period for the censored patients was 355 days (range 16-372 days), and just seven patients were still alive without Resonance failure > 1 year later. The women's IPSS scores tended to be lower than those of the men. Regarding the OABSS score, although the women's total score tended to be low, the difference between the men's and women's scores was nonsignificant. The bacteria detected from urine culture after stent insertion were more gram-positive than gram-negative. CONCLUSION: Metallic ureteric stenting using the Resonance stent is safe and effective for treating MUO. Subjective symptoms were relatively less in the female patients.

Investigation of the changes in the prostate, bladder, and rectal wall sizes during external beam radiotherapy.

AIM AND BACKGROUND: The change in the prostate size for radiotherapy has not yet been elucidated. The coverage of radiation dose is affected by changes in the prostate size. We evaluated the changes in the prostate, rectum, and bladder wall sizes during IMRT of fraction 2 Gy/day using MRI. MATERIALS AND METHODS: Twenty-four patients with prostate cancer were enrolled in this study. MRI was performed at three time points. While the initial MRI was performed before the start of radiotherapy (RT), the second MRI was performed at 38 Gy (range: 36-40 Gy), which represented the halfway point of the RT course. The last MRI was performed on the day of completion of the RT course (76 Gy; range: 74-78 Gy). We estimated the prostate, rectum, and bladder wall sizes at three time points. RESULTS: We observed no significant difference between the estimated sizes of the prostate during RT in all three phases. In addition, the volume of the rectal wall remained unchanged in all phases. However, the volume of the bladder wall significantly decreased from the initial to the last time points. Furthermore, the standard deviation (SD) obtained by subtracting the final size from the initial one was large (mean, 30.1; SD, 10.1). CONCLUSIONS: The volume of the bladder wall decreased during IMRT. The range of subtraction of the volume of the bladder wall was extensive. Thus, the estimation of the bladder wall may be useful to reduce the inter-fraction variation.

Comparison of MRI visualization between linearly placed iron-containing and non-iron-containing fiducial markers for prostate radiotherapy.

OBJECTIVE: Visualizing the gold marker (GM) in CT and MRI is critical, especially for registration in high-precision radiotherapy. GM sizes vary. Large markers are easily visualized in MRI. Small GMs show fewer artefacts in CT but are harder to detect in MRI because the signal is influenced by metal in MRI. Therefore, we compared MRI visualization between linearly placed new iron-containing marker and non-iron containing marker. METHODS: 27 patients underwent CT/MRI fusion-based intensity-modulated radiotherapy. The gold markers were placed by urologists. An iron-containing Gold Anchor™ (GA) marker (diameter, 0.28 mm; length, 10 mm) was placed by using a 22 G needle on one side of the prostate linearly. A non-iron-containing VISICOIL™ (VIS) marker (diameter, 0.35 mm; length, 10 mm) was placed by using a 19 G needle on the opposite side linearly. T2* weighted MRI was mostly performed. Two Radiation Oncologists and one Radiation Technologist evaluated and assigned visual quality scores (GA shape, CT artefacts, MRI signal voids). RESULTS: The mean visualization scores of artefacts were similar between GA and VIS in planning CT. GM visualization in MRI of the prostate was better for GA than for VIS. The visibility of the linear shape of the GA was 3.4-4.1 points when the VIS was 5 points (1 is worst and 5 is best). CONCLUSION: Visualization quality was similar between GA (iron-containing marker) and VIS (non-iron-containing marker) in planning CT, but was better for GA than for VIS in MRI. To achieve high-precision radiotherapy, an iron-containing gold marker was useful for CT and MRI registration. Advances in knowledge: An iron-containing fiducial marker was useful for CT and MRI registration, especially in high-precision radiotherapy, such as stereotactic body radiotherapy and intensity-modulated radiotherapy.

Efficacy of butylscopolamine in obtaining clear MR image for intensity-modulated radiotherapy for prostate cancer.

PURPOSE: The use of butylscopolamine in magnetic resonance imaging (MRI) of the prostate is controversial in the context of diagnostic imaging where local invasion and the presence of metastases are evaluated. However, in radiation oncology, MRI is performed as part of the simulation process, and the objectives differ to the diagnostic setting. MRI is primarily used for accurate target delineation; hence, the use of an agent to reduce intestinal peristalsis and increase image quality may be beneficial. The impact of butylscopolamine on MRI for radiation oncology purposes has not previously been described. The aim of this study was to evaluate the efficacy of butylscopolamine in MRI acquired for radiation oncology simulation of the prostate. METHODS AND MATERIALS: In total, 67 patients were enrolled in this study. Thirty-five patients received intramuscular injection of butylscopolamine (group A) and 32 patients did not (group B). Visualization of the prostate outline and detection of fiducial gold markers (GMs) in the prostate were evaluated on MRI. Two blinded radiation oncologists (ROs) and one radiation technologist (RT) scored the image quality of the detection of prostate outline and recognition of GMs in the prostate on a scale of 1-5 (1 = poor; 5 = excellent), and the results were evaluated using Mann-Whitney U test and p < 0.05 was considered as statistically significant. RESULTS: On MRI, group A was statistically superior to group B in terms of fiducial marker detection by two ROs (p < 0.01). However, there was no significant difference in RT scoring. Furthermore, on MRI, group A was statistically superior to group B in terms of the detection of the prostate outline by an RT. CONCLUSIONS: Butylscopolamine is effective with respect to detection of the prostate outline and GM recognition (without endorectal coil). The addition of butylscopolamine is simple and cost efficient. We recommend the use of butylscopolamine routinely to obtain good MR images, particularly in the detection of GMs.

Fiducial marker for prostate radiotherapy: comparison of 0.35- and 0.5-mm-diameter computed tomography and magnetic resonance images.

PURPOSE: When performing intensity-modulated radiotherapy for prostate cancer, a marker is inserted into the prostate to enable the recognition of its position using cone-beam computed tomography (CT). However, it is difficult to recognize the prostatic outline using CT alone. Magnetic resonance imaging (MRI) can depict the prostatic outline better than CT. In treatment plans using CT and MRI registration, various markers are used in institutions; however, the selection of an optimal marker size is difficult. Comparison of a different fiducial marker study was conducted using phantom, but no study in vivo was found. Therefore, we prospectively investigated the effects of different marker diameter sizes using CT and MR images. METHODS: Thirty-one consecutive patients were enrolled in this study. CT and MRI were performed 3 weeks after marker placement. The 0.35-mm-diameter marker was placed on the left side of the prostate, and the 0.5-mm-diameter marker was placed on the right side. The length of each marker was 10 mm. The better MRI image was selected between those obtained using T2*-two-dimensional weighted image (T2*2D) and T2*-three-dimensional weighted image (T2*3D). Two observers evaluated and scored the prostatic outline image quality as well as visualized the prostatic markers using CT and MRI. RESULTS: MRI was significantly superior to CT in depicting the prostatic outline. The CT artifacts were significantly lesser for the 0.35-mm-diameter marker than for the 0.5-mm-diameter marker. The degree of marker recognition using MRI was significantly better with the 0.5-mm-diameter marker. CONCLUSION: The 0.5-mm-diameter fiducial marker had significantly better visualization than the 0.35-mm-diameter marker. While CT artifacts were significantly worse with the 0.5-mm-diameter marker, the artifact level was tolerable for clinical practice. Therefore, we recommend the 0.5-mm-diameter diameter marker in terms of prostatic outline and marker visualization using MRI.

Novel penA mutations identified in Neisseria gonorrhoeae with decreased susceptibility to ceftriaxone isolated between 2000 and 2014 in Japan.

OBJECTIVES: We examined four clinical strains of Neisseria gonorrhoeae (GU030113, GU110095, GU110332 and GU110362) isolated between 2000 and 2014 in Japan, exhibiting ceftriaxone MICs of 0.5 mg/L, for mutations of the genes associated with penicillin resistance. METHODS: The penA, mtrR, porB1b (penB), ponA and pilQ genes of the strains were sequenced. PBP2s of the strains were aligned to the PBP2s associated with decreased susceptibility to oral cephalosporins, and PBP2s of previously reported strains with decreased susceptibility to ceftriaxone. RESULTS: GU030113 had PBP2 pattern X with an additional substitution of A502T. GU110095 had PBP2 pattern XXVII. GU110332 had PBP2 pattern XXXIV with an additional substitution of P552S. GU110362 had PBP2 composed of pattern X (amino acid positions 1-291) and pattern V (amino acid positions 292-576). GU030113, GU110095 and GU110332 had deletion of A in the mtrR promoter, G120K and A121D or A121N in PorB1b and L421P in PBP1. GU110362 had A40D in the repressor of MtrR and L421P in PBP1. The strains did not have mutations of pilQ1 and pilQ2. CONCLUSIONS: Addition of A502T to PBP2 pattern X in GU030113 and of P552S to PBP2 pattern XXXIV in GU110332 would possibly contribute to decreased susceptibility to ceftriaxone. In GU110095 and GU110362, it was suggested that, in addition to their altered PBP2s, the enhanced efflux pump, reduced permeability in the outer membrane, another altered target of ß-lactams and/or other mechanisms not identified in the present study might contribute to decreased susceptibility.

Male non-gonococcal urethritis: From microbiological etiologies to demographic and clinical features.

OBJECTIVES: To detect microorganisms responsible for male acute urethritis and to define the microbiology of non-gonococcal urethritis. METHODS: The present study comprised 424 men with symptoms and signs compatible with acute urethritis. Their urethral swabs and first-voided urine underwent detection of the microorganisms. Demographic characteristics and clinical features of Mycoplasma genitalium-, Ureaplasma urealyticum-, Haemophilus influenza-, adenovirus- or Herpes simplex virus-positive monomicrobial non-gonococcal urethritis, or all-examined microorganism-negative urethritis in heterosexual men were compared with urethritis positive only for Chlamydia trachomatis. RESULTS: Neisseria gonorrhoeae was detected in 127 men (30.0%). In 297 men with non-gonococcal urethritis, C. trachomatis was detected in 143 (48.1%). In 154 men with non-chlamydial non-gonococcal urethritis, M. genitalium (22.7%), M. hominis (5.8%), Ureaplasma parvum (9.1%), U. urealyticum (19.5%), H. influenzae (14.3%), Neisseria meningitidis (3.9%), Trichomonas vaginalis (1.3%), human adenovirus (16.2%), and Herpes simplex virus types 1 (7.1%) and 2 (2.6%) were detected. Although some features of monomicrobial non-chlamydial non-gonococcal urethritis or all-examined microorganism-negative urethritis were significantly different from those of monomicrobial chlamydial non-gonococcal urethritis, most features were superimposed. CONCLUSIONS: Predicting causative microorganisms in men with non-gonococcal urethritis based on demographic and clinical features is difficult. However, the present study provides useful information to better understand the microbiological diversity in non-gonococcal urethritis, and to manage patients with non-gonococcal urethritis appropriately.

[Three Patients with Acute Myocardial Infarction Associated with Targeted Therapy of Sorafenib for Metastatic Renal Cell Carcinoma : Case Report].

Sorafenib is a tyrosine kinase inhibitor (TKI) of the vascular endothelial growth factor receptor (VEGFR) used for advanced renal cell carcinoma. Treatment with sorafenib prolongs progression-free survival in patients with advanced clear-cell renal cell carcinoma. However, in spite of its therapeutic efficacy, sorafenib causes a wide range of adverse events. Cardiovascular adverse events have been observed when sorafenib was used with targeted agents. Although these adverse events like hypertension, reduced left ventricular ejection fraction, cardiac ischemia or infarction were manageable with standard medical therapies in most cases, some had a poor clinical outcome. We report three cases of acute myocardial infarction associated with sorafenib in patients with metastatic renal cell carcinoma.

Drug resistance-associated mutations in Mycoplasma genitalium in female sex workers, Japan.

Mycoplasma genitalium was detected in 21 (14.1%) of 149 vaginal swab samples and in 1 (0.7%) of 149 throat washing samples from female sex workers during 2013-2014 in Japan. Prevalences of M. genitalium with macrolide resistance-associated 23S rRNA mutations and fluoroquinolone resistance-associated parC alterations were 47.1% and 36.8%, respectively.

ALK Gene Translocation in Inflammatory Myofibroblastic Tumor of the Urinary Bladder: A Case Report.

A 26-year-old woman with gross hematuria was seen in a previous hospital. Magnetic resonance imaging (MRI) showed a tumor at the dome of the urinary bladder with invasion outside of the bladder wall. The patient underwent transurethral resection of the bladder tumor (TUR-BT). From the result of the pathological examination, the tumor was suggested to be carcinosarcoma of the bladder. The patient was then referred to our hospital for treatment. We performed radical cystectomy and ileal conduit diversion. Pathological examination of the excised specimen revealed an inflammatory myofibroblastic tumor as the basis for immunostaining of anaplastic lymphoma kinase (ALK).

Bacterial loads of Ureaplasma parvum contribute to the development of inflammatory responses in the male urethra.

Ureaplasma parvum, which has been recognised as a coloniser in the male urethra, is detected in some men with non-gonococcal urethritis. In this study, we quantified the 16 S rRNA genes of U. parvum by a real-time polymerase chain reaction-based assay in first-voided urine from 15 symptomatic and 38 asymptomatic men who were positive only for U. parvum. We also determined the leukocyte counts by automated quantitative urine particle analysis in their first-voided urine. Positive correlations were observed between copies of the 16 S rRNA genes of U. parvum/ml and the leukocyte counts/µl in first-voided urine (p = 0.0019). The loads of ≥10(4) copies of the 16 S rRNA gene/ml, corresponding to ≥5 × 10(3) cells of U. parvum/ml, were significantly associated with the presence of ≥12.5 leukocytes/µl in first-voided urine that might document the presence of inflammatory responses in the urethra. However, a large portion of the subjects (83.0%) had bacterial loads of <5 × 10(3) cells of U. parvum/ml, and 79.5% of them showed <12.5 leukocytes/µl. The ambiguity of the pathogenic role of U. parvum in non-gonococcal urethritis could, in part, be due to its low bacterial loads, which might not give rise to inflammatory responses in the male urethra.

[Small cell carcinoma of the prostate effectively treated for relatively long term: a case report].

A 72-year-old Japanese man was referred to a hospital because of urinary retention. Digital rectal examination revealed a stony, hard nodule in the prostate. A high level of serum PSA was not detected. Prostatic biopsy was performed, and pathological examination indicated adenocarcinoma of the prostate. He was referred to our hospital for treatment. Imaging examinations revealed no metastases (T4N0M0), so we re-evaluated the biopsy specimens. Immunohistochemical examination revealed prostatic small cell carcinoma. His levels of neuron-specific enolase (NSE) and pro-gastrin-releasing peptide (Pro-GRP) were high. We treated him with combination chemotherapy comprising irinotecan and cisplatin, and the treatment was effective. After four courses of the chemotherapy, levels of NSE and Pro-GRP had decreased, and the prostatic mass had decreased in size. Needle rebiopsy of the prostate demonstrated no evidence of malignancy. Adjuvant external beam radiation therapy was also performed. The patient iss till alive at 18 month after diagnosis with no evidence of relapse or metastasis of the disease.

Usefulness of quantifying leukocytes in first-voided urine to predict positivity for Chlamydia trachomatis in asymptomatic men at high risk for chlamydial infection.

Chlamydia trachomatis causes acute non-gonococcal urethritis, but some infected men are asymptomatic. We examined leukocytes in uncentrifuged first-voided urine (FVU) from asymptomatic men at high risk for chlamydial infection by automated urine particle analyzers to assess whether the quantification of urinary leukocytes could predict chlamydial infection in these men. We enrolled 209 asymptomatic men, whose female sexual partners had been diagnosed as having a genital chlamydial infection. Their FVU specimens were examined for quantification of leukocytes with automated urine particle analyzers and tested for Neisseria gonorrhoeae, C. trachomatis, Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma parvum, and Ureaplasma urealyticum by nucleotide acid amplification tests. Eleven men positive for N. gonorrhoeae or M. genitalium were excluded from further analysis. In the remaining 198 men, 84 positive for C. trachomatis (42.4%) had 1.8-1666.9 white blood cells (WBCs)/µl (median, 43.3 WBCs/µl) in their FVU, whereas 114 negative for C. trachomatis had 0.1-1378 WBCs/µl (median, 4.8 WBCs/µl). A receiver operating characteristic (ROC) curve was constructed to examine the sensitivity and specificity of leukocytes counts for predicting chlamydial infection. A cut-off point of leukocyte counts of 12.5 WBCs/µl was determined from the ROC curve, resulting in a sensitivity of 86.9% and specificity of 88.6% for predicting chlamydial infection. Leukocyte quantification in FVU by automated urine particle analyzers showed good performance in predicting the positivity and negativity for chlamydial infection in asymptomatic men. This test could potentially develop into a relevant tool for preselecting asymptomatic men prior to C. trachomatis screening.

Isolation of prostate cancer-related exosomes.

BACKGROUND/AIM: Exosomes have been demonstrated to be useful non-invasive biomarkers for several cancers including prostate cancer. Since normal cells also secrete exosomes, isolation of cancer-derived exosomes from blood is a prerequisite for their better understanding. The aim of this study is to establish the method for isolation of prostate cancer-related exosomes from blood. MATERIALS AND METHODS: Exosomes were collected from prostate cancer LNCaP and PC-3 cell lines by ultracentrifugation and by using magnetic beads conjugated with anti-CD9 antibody and anti-prostate-specific membrane antigen (PSMA) antibody. Prostate cancer-related exosomes were also isolated from the plasma of prostate cancer patients by anti-PSMA beads. Isolated exosomes were analyzed by western blotting. RESULTS: Exosomes were isolated from LNCaP cells by ultracentrifugation, contained PSMA and androgen receptor (AR). AR was also detected in exosomes isolated from LNCaP cells by anti-PSMA and anti-CD9 beads, showing that AR is present in prostate cancer-related exosomes. The amount of CD9 in isolated exosomes was much higher in advanced and chemo-resistant prostate cancer patients than in prostate cancer patients without metastasis and healthy volunteers, indicating that patients with aggressive prostate cancer exhibit higher levels of prostate cancer-related exosomes in blood. CONCLUSION: The immunoaffinity-based method we developed is capable of isolating prostate cancer-related exosomes from blood, the use of which will enhance investigation processes on exosomes in prostate cancer.