Surgical management of prepubertal testicular tumors: A 30-year study in our institution.

OBJECTIVES: The 2021 European Association of Urology-European Society for Paediatric Urology guidelines on Pediatric Urology recommended testis-sparing surgery (TSS) as the primary approach to treat prepubertal testicular tumors exhibiting favorable preoperative ultrasound diagnoses. However, prepubertal testicular tumors are rare and clinical data regarding them is limited. Here, we analyzed the surgical management of prepubertal testicular tumors based on cases observed over approximately 30 years. METHODS: Data were retrospectively reviewed from medical records of consecutive patients aged <14 years with testicular tumors who received treatment at our institution between 1987 and 2020. We compared patients by their clinical characteristics, namely, those who underwent TSS versus radical orchiectomy (RO) and those who received surgery in 2005 onward versus prior to 2005. RESULTS: We identified 17 patients, with a median age at surgery of 3.2 years (range 0.6-14.0) and a median tumor size of 15 mm (range 6-67). The tumor size was significantly smaller in patients who underwent TSS than in those who underwent RO (p = 0.007). Patients treated in 2005 onward were more likely to undergo TSS than those treated prior to 2005 (71% vs. 10%, respectively), without significant differences in tumor size or the rate of preoperative ultrasound. No TSS cases required conversion to RO. CONCLUSIONS: Recent improvements in ultrasound imaging technology allow for more accurate clinical diagnosis. Therefore, the indications of TSS for prepubertal testicular tumors can be judged based not only on the tumor size but also on the diagnosis of benign tumors by preoperative ultrasound.

A Randomized, Single-Blind Clinical Trial Comparing Robotic-Assisted Fluoroscopic-Guided with Ultrasound-Guided Renal Access for Percutaneous Nephrolithotomy.

PURPOSE: We conducted a randomized, single-blind clinical trial comparing the surgical outcomes of robotic-assisted fluoroscopic-guided (RAF group) and ultrasound-guided (US group) renal access in mini-percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: We recruited patients who underwent mini-PCNL with ureteroscopic assistance for large renal stones between January 2020 and May 2021. Block randomization was performed using online software. Automated needle target with x-ray was used for fluoroscopic-guided renal access in the RAF group. PCNL was performed by residents using a pneumatic lithotripsy system with 16.5Fr/17.5Fr tracts. The primary outcome was single puncture success, and the secondary outcomes were stone-free rate, complication rate, parameters measured during renal access and fluoroscopy time. RESULTS: In total, 71 patients (35 in US group, 36 in RAF group) were enrolled. No difference was seen in the single puncture success rate between the US and RAF groups (34.3% and 50.0%, p=0.2). In 14.3% cases in the US group vs no cases in the RAF group, the resident was unable to obtain access due to difficult targeting (p=0.025). The mean number of needle punctures was significantly fewer, and the median duration of needle puncture was shorter in the RAF group (1.83 vs 2.51 times, p=0.025; 5.5 vs 8.0 minutes, p=0.049, respectively). The stone-free rate at 3 months after surgery was 83.3% and 70.6% in the RAF and US groups, respectively (p=0.26). Multivariate analysis revealed that RAF guidance reduced the mean number of needle punctures by 0.73 times (p=0.021). CONCLUSIONS: RAF renal access in mini-PCNL may have further potential applications in this field.

Low Serum Inhibin B/Follicle-Stimulating Hormones and Anti-Müllerian Hormone/Follicle-Stimulating Hormones Ratios as Markers of Decreased Germ Cells in Infants with Bilateral Cryptorchidism.

PURPOSE: In cryptorchidism, germ cell development failure presents from infancy and may be reflected by altered hormonal levels produced by Sertoli cells. Our object was to assess for associations between serum hormone levels and testicular histopathology in cryptorchidism with an infertility risk according to the pretreatment undescended testicular positions. MATERIALS AND METHODS: Prepubertal cryptorchid boys aged 7-91 (median 20) months who underwent orchidopexy between 2014 and 2019 were included (122 unilateral [median 19 months {range 7-91}], 23 bilateral [24 months {11-81}]). We evaluated the pretreatment testicular position and size; serum hormone levels; and the mean number of germ cells per tubule transverse section (G/T). We also performed a subgroup analysis of boys aged ≤24 months at orchidopexy. RESULTS: Serum inhibin B levels and G/T were significantly lower in bilateral than in unilateral cryptorchid boys (median 96 [range 46-197] pg/ml vs 125 [21-354] pg/ml, p=0.026; 0.20 [0-2.59] vs 0.65 [0-4.55], p <0.001, respectively). Inhibin B/follicle-stimulating hormones (FSH) and anti-Müllerian hormone (AMH)/FSH ratios were positively correlated with G/T in bilateral cryptorchid boys aged ≤24 months (12, p=0.008 and p=0.019, respectively). Low inhibin B/FSH and AMH/FSH ratios and high FSH were predictors of impaired G/T as per receiver operating characteristic curves (p=0.019, p=0.004 and p=0.004, respectively), whereas in unilateral cryptorchid boys aged ≤24 months, serum hormone levels and G/T did not differ with the pretreatment testicular positions. CONCLUSIONS: In bilateral cryptorchid boys aged ≤24 months at orchidopexy, low inhibin B/FSH and AMH/FSH ratios may reflect impaired G/T and future infertility risk.

The protective function of invariant natural killer T cells in the relapse of experimental autoimmune uveoretinitis.

Experimental autoimmune uveoretinitis (EAU) in mice provides a useful platform to study the pathogenesis and experimental therapeutics of human uveitis. One often used EAU model employs C57BL/6 (B6) mice sensitized with a peptide residue having 1 to 20 amino acids of human interphotoreceptor retinoid binding protein (hIRBP1-20). The model using the B6 background has permitted a liberal use of genetically engineered strains and has provided insights for understanding uveoretinitis. However, this is usually acute/monophasic and does not represent human uveoretinitis that is characterized as a chronic/recurrent disease. Several chronic/recurrent EAU models have been developed; of these, we employed administration of staphylococcal enterotoxin B (SEB) for relapse in the present study, and found that recurrence was induced at day 24 after primary immunization, which is thought to be the convalescent phase. We reported the activation of invariant natural killer T (iNKT)-cells upon primary immunization of the EAU model mice with the ligand RCAI-56, which was found to mitigate the disease in our previous study. Here, we first attempted to ameliorate EAU in the relapse model using a preventive regimen by activating iNKT cells at the same time relapse induction (day 24) or in a regimen after 3 days of relapse induction (day 27). The preventive as well as post-inductive regimens were successful in reducing histopathological scores by inhibiting the Ag-specific Th17-biased response. Collectively, activation of iNKT cells may be useful to mitigate the relapse response of EAU induced with SEB.

Antireflux endoscopic injection therapy in post-pubertal patients via techniques adopted for the dilated ureteral orifice: a retrospective single-center study.

BACKGROUND: To investigate the efficacy and safety of endoscopic injection therapy for vesicoureteral reflux in post-pubertal patients with dilated ureteral orifice via modified hydrodistension implantation techniques. METHODS: We retrospectively reviewed medical records including operational procedure and clinical course of all consecutive patients over 12 years old with a history of injection therapy. Endoscopic injection of dextranomer/hyaluronic acid copolymer was performed under hydrodistension implantation technique with some modifications in order to inject through dilated ureteral orifice align with the intramural ureter. Technical selections were done according to hydrodistension grade of the ureteral orifice. Voiding cystourethrography was evaluated at 3 months postoperatively. Hydronephrosis was evaluated using ultrasonography preoperatively until 6 months postoperatively. RESULTS: From 2016 to 2019, 12 patients (all female, 16 ureteral units; median age 32 [range 15-61] years) underwent endoscopic injection therapy at one of our institutions. We have identified grade II vesicoureteral reflux in 5 ureters, grade III in 8, and grade IV in 3 ureters. Grade 3 ureteral-orifice dilation were presented in 12 ureters (75%), grade 2 in 3 and grade 1 in 1 ureter in the present cases. Postoperatively, vesicoureteral reflux was diminished to grade 0 in 12 ureteral units (75%), decreased to grade I in 3 (9%), and remained grade III in 1 (6%). Three patients reported dull flank pain for several days postoperatively and there was 1 case of acute pyelonephritis. Temporary hydronephrosis was confirmed in 3 ureteral units (19%) at 1 month postoperatively. Median follow-up duration was 23 (range 13-63) months long. Although, 3 patients were experienced f-UTI 1-2 times, repeated VCUG showed no VUR recurrence. CONCLUSIONS: According to hydrodistension grade of the ureteral orifice, endoscopic injection therapy via modified hydrodistension implantation technique is an effective and safe treatment for vesicoureteral reflux in post-pubertal female patients with dilated ureteral orifice. While ureteral deformities or a history of anti-reflux surgery may increase the risks, these can be managed with appropriate methods that ensure sufficient mound appearance and height.

Ureteroscopy-assisted puncture for ultrasonography-guided renal access significantly improves overall treatment outcomes in endoscopic combined intrarenal surgery.

OBJECTIVES: To assess the impact and availability of ureteroscopy-assisted puncture for percutaneous renal access during ultrasonography-guided miniaturized (mini)-endoscopic combined intrarenal surgery for large volume renal and/or proximal ureteral stones. METHODS: We conducted a multi-institutional retrospective cohort study for urolithiasis treatment. Data from a total of 313 patients who underwent mini-endoscopic combined intrarenal surgery to treat renal and/or ureteral stones between January 2016 and April 2020 were collected. We compared the outcomes between ultrasonography-guided mini-endoscopic combined intrarenal surgery with and without ureteroscopy-assisted puncture (ureteroscopy-assisted puncture(+) group [n = 126] and ureteroscopy-assisted puncture(-) group [n = 187] group, respectively). The primary outcome was requirement for additional surgical intervention. Secondary outcomes were stone-free rate, complications and total procedure, fluoroscopy, hospital stay, and postoperative ureteral stent placement durations. RESULTS: The ureteroscopy-assisted puncture(+) group had a lower additional surgical intervention rate and a higher stone-free rate immediately after and 3 months after surgery than the ureteroscopy-assisted puncture(-) group (5.6% vs 19.7%, P < 0.001; 82.5% vs 65.8%, P = 0.001; 59.5% vs 44.6%, P = 0.011). The median total procedure, fluoroscopy, and postoperative ureteral stent placement durations were 18 min, 3 min, and 5 days shorter, respectively, in the ureteroscopy-assisted puncture(+) group. Multivariate analyses showed that ureteroscopy-assisted puncture was associated with a decreased risk of additional surgical intervention (odds ratio 0.31, P = 0.011) and postoperative infection (odds ratio 0.34, P = 0.003) and decreased total procedure (estimate = -11 min; P = 0.011), fluoroscopy (estimate = -3 min; P = 0.034), and postoperative ureteral stent placement (estimate = -8 days; P = 0.011) durations. Female patients and those with smaller stone volumes or without hydronephrosis were identified as ideal ureteroscopy-assisted puncture candidates. CONCLUSIONS: Ureteroscopy-assisted puncture during mini-endoscopic combined intrarenal surgery could provide favorable surgical outcomes, especially in female patients without collecting system obstruction.

Appropriate timing of performing abdominal ultrasonography and termination of follow-up observation for antenatal grade 1 or 2 hydronephrosis.

BACKGROUND: Most cases of antenatal the Society of Fetal Urology (SFU) grade 1or 2 hydronephrosis (HN) improve or resolve spontaneously with conservative treatment. However, there is no consensus on the duration of follow-up for cases of grade 1or 2 HN. The aim of this study was to determine the need for continuous follow-up period and new management of children with antenatal grade 1or 2 HN. METHODS: Subjects underwent ultrasonographic assessment for HN according to the SFU classification. We retrospectively evaluated 112 patients with postnatal grade 1 HN and 69 with grade 2 HN using abdominal ultrasonography between January 2010 and December 2017. We examined the change in HN grade on repeat ultrasonography. Kaplan-Meier method was used to show the effect of HN grade on the rate of HN changes. RESULTS: The mean follow-up duration was 44.9 ± 36.4 months (range 12-274). Initial SFU grade 1 HN disappeared in 47.0% of cases at 12 months, 66.4% at 24 months and 73.2% at 48 months. Initial SFU grade 2 HN showed improvement in grade in 74.7% of cases at 12 months, 88.3% at 24 months and 89.5% at 48 months. However, 14.6% of SFU grade 1 and 2.8% of SFU grade 2 cases increased in grade and of the 17 cases, 16 cases worsened within the first 6 months. No cases with increased grade required pyeloplasty. Initial disappearance and later reappearance of HN occurred in 40.5% of SFU grade 1 and 2 cases. The mean duration of later reappearance of HN was 39.1 ± 36.2 months (range 12-137). No cases showed reappearance of HN after more than 1 year. CONCLUSIONS: Ultrasonography within the first 6 months was necessary for management of children with antenatal grade 1or 2 HN, because some patients showed worsening. After that, it is considered safe to spread the follow-up interval for stable cases. Most cases of grade 1or 2 HN resolved spontaneously, however a few cases reappeared within 1 year. Therefore, ultrasonography after 1 year was necessary in children with HN that spontaneously disappeared. The appropriate time to end the follow-up was considered to have been after 1 year or more has passed since the disappearance was confirmed.

Low bone mineral density is a potential risk factor for symptom onset and related with hypocitraturia in urolithiasis patients: a single-center retrospective cohort study.

BACKGROUND: Patients with urolithiasis have a lower bone mineral density (BMD) than those without stones, suggesting a potential correlation between calcium stone formation and bone resorption disorders, including osteopenia and osteoporosis. METHODS: To investigate the influence of BMD on clinical outcomes in urolithiasis, we performed a single-center retrospective cohort study to analyze patients with urolithiasis who underwent both BMD examination and 24-h urine collection between 2006 and 2015. Data from the national cross-sectional surveillance of the Japanese Society on Urolithiasis Research in 2015 were utilized, and additional data related to urinary tract stones were obtained from medical records. The primary outcome was the development of stone-related symptoms and recurrences during follow-up. A total of 370 patients were included in this 10-year study period. RESULTS: Half of the patients had recurrent stones, and the two-thirds were symptomatic stone formers. While only 9% of patients had hypercalciuria, 27% and 55% had hyperoxaluria and hypocitraturia, respectively. There was a positive correlation between T-scores and urinary citrate excretion. Both univariate and multivariate analyses demonstrated that female sex was associated with recurrences (odds ratio = 0.44, p = 0.007), whereas a T-score < - 2.5 and hyperoxaluria were associated with symptoms (odds ratio = 2.59, p = 0.037; odds ratio = 0.45, p = 0.01; respectively). CONCLUSION: These results revealed that low T-scores might cause symptoms in patients with urolithiasis, suggesting the importance of BMD examination for high-risk Japanese patients with urolithiasis having hypocitraturia.

Active Phagocytosis and Diachronic Processing of Calcium Oxalate Monohydrate Crystals in an in vitro Macrophage Model.

BACKGROUND: We previously discovered that renal macrophages (Mφs) phagocytose renal calcium oxalate monohydrate (COM) crystals. This study investigated the processing of engulfed crystals using in vitro models. METHODS: J774.1 mouse Mφs were exposed to COM crystals and observed for 24 h using polarized light microscopy with/without cytochalasin B (CB), an inhibitor of phagocytosis, to confirm active crystal phagocytosis. LysoTracker and immunohistochemical staining using transmission electron microscopy for lysosomal-associated membrane protein 1 were used to confirm engulfed COM crystal uptake into lysosomes. Diachronic tracking of specific Mφs was performed to capture the entire course of engulfed COM crystal processing using polarized light microscopy. Follow-up studies of fluorescent COM (f-COM) crystals using imaging cytometry were performed in the presence and absence of nigericin to dissipate the pH gradient in acidic organelles. RESULTS: Phagocytosis rates increased with COM density and were significantly lower in cells treated with CB (p < 0.01). We observed that engulfed crystals colocalized within lysosomes of the Mφs; moreover, diachronic observation indicated that the engulfed COM crystals were subdivided during Mφ division and eliminated by the 7th day of culture. Additionally, imaging cytometry showed that the fluorescence level of f-COM crystals in the nigericin (-) group after 48 h was significantly lower than that in the nigericin (+) group. CONCLUSIONS: This study confirmed active phagocytosis and lysosomal processing of engulfed COM crystals by Mφs. This discovery is expected to contribute to the development of future drugs that enhance the COM crystal phagocytic ability of Mφs.

Systematic regional lymph node dissection for upper tract urothelial carcinoma improves patient survival.

OBJECTIVE: Unlike for bladder cancer, the impact of regional lymph node dissection for upper tract urothelial carcinoma is unclear. We explored whether patient survival was influenced by systematic regional lymph node dissection, using resection templates according to the main tumor location, during radical nephroureterectomy for upper tract urothelial carcinoma. METHODS: The systematic regional lymph node dissection group was defined as cases in which the dissection of nodes and surrounding tissues followed the established template, and the non-systematic regional lymph node dissection group as cases undergoing limited or no lymph node dissection. We performed radical nephroureterectomy on 98 consecutive patients with various stages of upper tract urothelial carcinoma from May 1994 to September 2014 at our institution. Of these, 77 patients with cTanyN0M0 of upper tract urothelial carcinoma undergoing radical nephroureterectomy were grouped into systematic regional lymph node dissection or non-systematic regional lymph node dissection cohorts according to the extent of dissection, and their outcomes compared. RESULTS: Forty-four patients were categorized as systematic regional lymph node dissection and 33 as non-systematic regional lymph node dissection, including 17 with more limited nodal dissection and 16 with no nodal dissection. Five-year recurrence-free survival and cancer-specific survival were significantly higher in the systematic regional lymph node dissection (93% and 94%, respectively) than in the non-systematic regional lymph node dissection group (75% and 77% recurrence-free survival and cancer-specific survival, respectively). Further, 5-year recurrence-free survival and cancer-specific survival of muscle-invasive upper tract urothelial carcinoma (pT2-4) were significantly higher in the systematic regional lymph node dissection (87% and 91%, respectively) than in the non-systematic regional lymph node dissection group (59% and 62%, respectively) (P = 0.0237 and P = 0.0224). Neither recurrence-free survival nor cancer-specific survival was significantly prolonged by systematic dissection in patients with pTis-1 histology. CONCLUSIONS: Systematic regional lymph node dissection during radical nephroureterectomy for cTanyN0M0 upper tract urothelial carcinoma patients has a significantly beneficial impact on survival compared with patients undergoing more limited dissection, especially in the cases involving muscle invasion.

Involvement of the bone morphogenic protein/SMAD signaling pathway in the etiology of congenital anomalies of the kidney and urinary tract accompanied by cryptorchidism.

BACKGROUND: Congenital anomalies of the kidney and urinary tract (CAKUT), such as renal dysplasia, hydronephrosis, or vesicoureteral reflux, are the most common causes of end-stage renal disease. However, the genetic etiology of CAKUT remains unclear. In this study, we performed whole exome sequencing (WES) to elucidate the genetic etiology of symptomatic CAKUT and CAKUT accompanied by cryptorchidism. METHODS: Three patients with unilateral renal dysplasia accompanied by ipsilateral cryptorchidism were included in this analysis. Genomic DNA was extracted from peripheral blood, and WES was performed. Disease-specific single nucleotide polymorphisms (SNPs) were determined by comparison with the human genome reference sequence (hg19). Additionally, we searched for SNPs that were common to all three patients, with a particular focus on the coding regions of the target genes. RESULTS: In total, 8710 SNPs were detected. Of the genes harboring these SNPs, 32 associated with renal or testicular development were selected for further analyses. Of these, eight genes (i.e., SMAD4, ITGA8, GRIP1, FREM1, FREM2, TNXB, BMP8B, and SALL1) carried a single amino acid substitution that was common to all three patients. In particular, SNPs in SMAD4 (His290Pro and His291Pro) have not been reported previously in patients with symptomatic CAKUT. Of the candidate genes, four genes (i.e., ITGA8, GRIP1, FREM1, and FREM2) were Fraser syndrome-related genes, encoding proteins that functionally converged on the glial cell-derived neurotrophic factor/RET/bone morphogenic protein (BMP) signaling pathways. As another candidate gene, the protein encoded by BMP8B activates the nuclear translocation of SMAD4, which regulates the expression of genes associated with the differentiation of primordial germ cells or testicular development. Additionally, BMP4, a member of the BMP family, regulates the interaction between metanephric mesenchyme and ureteric buds by suppressing GDNF. CONCLUSIONS: Taken together, our findings suggested that the development of the kidney and urinary tract is intimately linked with that of male reproductive organs via BMP/SMAD signaling pathways.

[Evaluation of CT-Guided Percutaneous Needle Biopsy for Diagnosis of Renal Tumor].

We performed computed tomographic (CT)-guided percutaneous needle biopsy for renal tumors that were difficult to diagnose or were inoperable malignant renal tumors. Nineteen patients who underwent CT-guided percutaneous needle biopsy between November 2007 and March 2015 at Hamamatsu University Hospital were included in this study. The median tumor diameter was 78 mm (40-140 mm). Seventeen patients were diagnosed pathologically by biopsy, but 2 patients could not be diagnosed despite the existence of adequate sample volume. One patient had an adverse complication ; fever (CTCAE ver 4.0 grade 1). The median duration of follow-up was 21 months (0-111 months), no one had tumor seeding along a needle tract. CT-guided percutaneous needle biopsy of renal tumors is helpful for pathological diagnosis and further treatment planning. However, there are still some limitations to obtain an accurate diagnosis.

[Suicide attempt by an interstitial cystitis patient : a case report].

We report a suicide attempt by an interstitial cystitis patient. A 68-year-old woman consulted several clinics with complaints of urinary frequency and bladder pain, but her symptoms did not improve. She was admitted to our hospital and diagnosed with interstitial cystitis. Hydrodistention was performed, and the urethral catheter removed one day after surgery. The next day, the patient was afraid that her symptoms had not improved and, due to this physical and mental distress, cut her wrist with a razor. Vascular anastomosis and neuroanastomosis were performed accordingly. Eighteen months after hydrodistention, the patient's symptoms of interstitial cystitis have much improved.

[Acute renal failure due to obstructive ureteral stone associated with norovirus gastroenteritis in an infant with congenital solitary kidney].

We report a 35 month-old boy with acute renal failure caused by an obstructive ureteral stone associated with norovirus gastroenteritis. He visited his family physician because of fever, abdominal pain and vomiting. He was diagnosed as acute gastroenteritis. The symptoms relieved once, but abdominal pain and vomiting recurred two days after the visit and the volume of urine decreased. He was diagnosed as norovirus gastoenteritis and acute renal failure which was unresponsive to fluid replacement. Ultrasound study of the abdomen showed a solitary kidney with mild hydronephrosis. He was then admitted to our hospital. He was finally diagnosed as acute postrenal failure due to obstructive ureteral stone with left solitary kidney by abdominal computer tomography (CT). We performed transurethral catheterization immediately. The creatinine and blood urea nitrogen returned to normal level in 2 days. The CT performed on the 28th day post operation showed disappearance of the stone after uric alkalization. Recently, some cases of postrenal failure due to bilateral obstructive ureteral stones, mainly ammonium acid urate stones, associated with viral gastroenteritis were reported. As clinical features, they are common in boys three years or younger after an episode of rotavirus gastroenteritis with high uric acid concentration. By far, the most common cause of acute renal failure in patients with severe gastroenteritis is prerenal failure resulting from hypovolemia. But postrenal cause due to bilateral obstructive stones should be taken in a consideration.

Correction of substitution, deletion, and insertion mutations by 5'-tailed duplexes.

Germline and somatic mutations cause various diseases, including cancer. Clinical applications of genome editing are keenly anticipated, since it can cure genetic diseases. Recently, we reported that a 5'-tailed duplex (TD), consisting of an approximately 80-base editor strand oligodeoxyribonucleotide and a 35-base assistant strand oligodeoxyribonucleotide, could edit a target gene on plasmid DNA and correct a single-base substitution mutation without an artificial nuclease in human cells. In this study, we assessed the ability of the TD to correct base substitution mutations located consecutively or separately, and deletion and insertion mutations. A TD with an 80-base editor strand was co-introduced into human U2OS cells with plasmid DNA bearing either a wild-type or mutated copepod green fluorescent protein (copGFP) gene. Among the mutations, three-base consecutive substitutions were efficiently repaired. The correction efficiencies of deletion mutations were similar to those of substitution mutations, and two to three times higher than those of insertion mutations. Up to three-base substitution, deletion, and insertion mutations were excellent targets for correction by TDs. These results suggested that the TDs are useful for editing disease-causing genes with small mutations.

Identification of hypoxia-induced metabolism-associated genes in canine tumours.

Canine tumours including urothelial carcinoma, lung adenocarcinoma, mammary gland tumour, squamous cell carcinoma, and melanoma have been identified as causes of death, but effective therapies are limited due to insufficient knowledge of the molecular mechanisms involved. Within the tumour microenvironment, hypoxia activates hypoxia-inducible factor 1α (HIF1α) in tumour cells. High HIF1α expression correlates with enhanced glycolysis and poorer outcomes in human cancers. However, the molecular mechanisms underlying hypoxic tumour cells remain elusive in dogs. In our study, we investigated upregulated genes in a canine malignant melanoma cell line during hypoxia using RNA-sequencing analysis. Glycolysis and HIF1 signalling pathways were upregulated in hypoxic melanoma cells. HIF1α knockout melanoma cells revealed that the glycolysis marker MCT4 is regulated by HIF1α activation. Hypoxia induces high lactate secretion due to enhanced glycolysis in canine melanoma cells. Furthermore, we examined monocarboxylate transporter 4 (MCT4) expression in malignant melanoma and eight other types of canine tumour tissues using immunohistochemistry (IHC). Membrane-localized MCT4 protein was mostly detected in urothelial carcinoma and lung adenocarcinoma rather than malignant melanoma. We conclude that canine MCT4 protein plays a role in lactic acid efflux from glycolytic cells and may serve as a marker for hypoxia and glycolysis in canine tumours. These findings could inform future therapeutic strategies targeting MCT4.

Successful treatment with enfortumab-vedotin of metastatic signet ring cell cancer expressing nectin-4 and originating from the bladder.

Introduction: As an aggressive adenocarcinoma phenotype, primary signet ring cell carcinoma of the urinary bladder is an extremely rare variant. The prognosis of metastatic signet ring cell carcinoma of the urinary bladder is extremely poor and the clinical course for its specific pathogenesis remains unelucidated. Case presentation: A 64-year-old Japanese male patient was diagnosed with invasive urothelial carcinoma with glandular differentiation of a signet ring cell-type with pT4aN0M0, and he was eventually diagnosed with metastatic signet ring cell carcinoma of the urinary bladder. He was initially responsive to systemic combination induction chemotherapy of S-1 and cisplatin followed by avelumab switch maintenance therapy; however, signet ring cell carcinoma of the urinary bladder relapse occurred in the pathological findings of a biopsy from the right thigh. Immunohistochemical analysis of this specimen identified strong positive staining for nectin-4 and, following enfortumab-vedotin treatment, the patient showed a good response. Conclusion: We thus describe a rare case of metastatic signet ring cell carcinoma of the urinary bladder with nectin-4 expression diagnosed by a biopsy of a metastatic site.