Immunohistochemical Profiling of SSTR2 and HIF-2α with the Tumor Microenvironment in Pheochromocytoma and Paraganglioma.

Metastatic pheochromocytomas and paragangliomas (PPGLs) are rare endocrine malignancies with limited effective treatment options. The association between the tumor microenvironment (TME) with somatostatin receptor 2 (SSTR2) and hypoxia-induced factor-2α (HIF-2α) in PPGLs, critical for optimizing combination therapeutic strategies with immunotherapy, remains largely unexplored. To evaluate the association of SSTR2 and HIF-2α immunoreactivity with the TME in patients with PPGLs, we analyzed the expression of SSTR2A, HIF-2α, and TME components, including tumor-infiltrating lymphocytes (CD4 and CD8), tumor-associated macrophages (CD68 and CD163), and PD-L1, using immunohistochemistry in patients with PPGLs. The primary outcome was to determine the association of the immune profiles with SSTR2A and HIF-2α expression. Among 45 patients with PPGLs, SSTR2A and HIF2α were positively expressed in 21 (46.7%) and 14 (31.1%) patients, respectively. The median PD-L1 immunohistochemical score (IHS) was 2.0 (interquartile range: 0-30.0). Positive correlations were observed between CD4, CD8, CD68, and CD163 levels. A negative correlation was found between the CD163/CD68 ratio (an indicator of M2 polarization) and SSTR2A expression (r = -0.385, p = 0.006). HIF-2α expression showed a positive correlation with PD-L1 IHS (r = 0.348, p = 0.013). The co-expression of PD-L1 (HIS > 10) and HIF-2α was found in seven patients (15.6%). No associations were observed between SDHB staining results and the CD163/CD68 ratio, PD-L1, or SSTR2A expression. Our data suggest the potential of combination therapy with immunotherapy and peptide receptor radionuclide therapy or HIF-2α inhibitors as a treatment option in selected PPGL populations.

Clinical characteristics and survival outcomes of elderly patients with de novo metastatic germ cell tumors.

OBJECTIVES: To determine the outcomes for elderly patients with de novo metastatic germ cell tumors and the influence of patient age on adherence to standard chemotherapy. METHODS: A total of 150 patients who were initially diagnosed with metastatic germ cell tumors and treated at our institution between 2007 and 2021 were included. Patients were classified according to three age groups: aged <40, 40-49, and ≥50 years. Clinicopathological features, adherence to standard first-line chemotherapy, overall survival, and disease-free survival were compared between these groups. We also analyzed the outcomes of patients who received low-intensity induction chemotherapy due to adverse events and/or comorbidities. RESULTS: There was no significant difference in any of the survival outcomes and in the rate of adherence to standard first-line chemotherapy between the three age groups, although elderly patients with intermediate/poor prognosis group tended to receive less-intense chemotherapies. The rate of febrile neutropenia as a chemotherapy-related adverse event was significantly higher in patients aged ≥50 years. No statistical significance in survival outcomes was detected between the group of patients who received relatively low-intensity induction chemotherapy and those who received adequately intensive planned chemotherapy. CONCLUSIONS: The adherence rate of standard fist-line chemotherapy of elderly patients is almost comparable to that of younger patients, although some adverse events should be carefully managed. Even elderly patients with metastatic germ cell tumors can aim for equivalently good survival outcome like younger populations, with effort to adhere to standard chemotherapy.

[The development of innovative therapeutic drugs targeting hypoxia responses].

The 2019 Nobel Prize in Physiology or Medicine was awarded to Dr. William G. Kaelin Jr, Dr. Peter J. Ratcliffe, and Dr. Gregg L. Semenza for their elucidation of new physiological mechanisms "How cells sense and adapt to oxygen availability". Moreover, two different drugs, HIF-PH inhibitors and HIF-2 inhibitors were also developed based on the discovery. Interestingly, those three doctors have different backgrounds as a medical oncologist, a nephrologist, and a pediatrician, respectively. They have started the research based on their own unique perspectives and eventually merged as "the elucidation of the response mechanism of living organisms to hypoxic environments". In this review, we will explain how the translational research that has begun to solve unmet clinical needs successfully contributed to the development of innovative therapeutic drugs.

Significant reduction in burden of metastatic disease by intermittent docetaxel therapy in a patient with castration-resistant prostate cancer.

Intermittent docetaxel therapy (IDT) is rarely used nowadays as a treatment option for men with metastatic castration-resistant prostate cancer (mCRPC) because of the widespread availability of androgen receptor axis-targeted therapy, which is less toxic. Therefore, there is limited information available on whether IDT has a clinical benefit in the treatment of men with mCRPC. This report describes the case of a 66-year-old man with a diagnosis of cT2N1M0 prostate cancer who underwent neoadjuvant combined androgen blockade and whole-pelvis radiation therapy. However, the tumor had progressed to mCRPC with metastasis to the bladder and a left pelvic lymph node within 2 years. Docetaxel had been administered as first-line chemotherapy, and the patient achieved a complete response in terms of the bladder metastasis. Docetaxel was stopped after 15 cycles. When a durable response had been maintained for more than 2 years, during which only androgen deprivation therapy was administered, the patient was switched to observation only. However, his prostate-specific antigen level gradually increased. Abiraterone was started as second-line therapy, during which there was a rapid increase in the PSA level. Computed tomography revealed further enlargement of the left pelvic lymph node, bladder metastasis, metastasis to the left common iliac lymph nodes, and several disseminated nodules around the bladder. Docetaxel was reintroduced as IDT for third-line therapy, and a complete response was achieved for all metastases, with the exception of the metastasis in the left pelvic lymph node. Thus far, the patient has survived for more than 7 years after starting docetaxel as first-line therapy for mCRPC. IDT is potentially useful in a subgroup of patients with mCRPC and could achieve long-term survival. Comprehensive genomic profiling may help physicians to select patients with mCRPC who are more likely to benefit from docetaxel than other systemic therapy.

Newly developed preclinical models reveal broad-spectrum CDK inhibitors as potent drugs for CRPC exhibiting primary resistance to enzalutamide.

Androgen-deprivation therapy is a standard treatment for advanced prostate cancer. However, most patients eventually acquire resistance and progress to castration-resistant prostate cancer (CRPC). In this study, we established new CRPC cell lines, AILNCaP14 and AILNCaP15, from LNCaP cells under androgen-deprived conditions. Unlike most pre-existing CRPC cell lines, both cell lines expressed higher levels of androgen receptor (AR) and prostate-specific antigen (PSA) than parental LNCaP cells. Moreover, these cells exhibited primary resistance to enzalutamide. Since AR signaling plays a significant role in the development of CRPC, PSA promoter sequences fused with GFP were introduced into AILNCaP14 cells to conduct GFP fluorescence-based chemical screening. We identified flavopiridol, a broad-spectrum CDK inhibitor, as a candidate drug that could repress AR transactivation of CRPC cells, presumably through the inhibition of phosphorylation of AR on the serine 81 residue (pARSer81 ). Importantly, this broad-spectrum CDK inhibitor inhibited the proliferation of AILNCaP14 cells both in vitro and in vivo. Moreover, a newly developed liver metastatic model using AILNCaP15 cells revealed that the compound attenuated tumor growth of CRPC harboring highly metastatic properties. Finally, we developed a patient-derived xenograft (PDX) model of CRPC and DCaP CR from a patient presenting therapeutic resistance to enzalutamide, abiraterone, and docetaxel. Flavopiridol successfully suppressed the tumor growth of CRPC in this PDX model. Since ARSer81 was found to be phosphorylated in clinical CRPC samples, our data suggested that broad-spectrum CDK inhibitors might be a potent candidate drug for the treatment of CRPC, including those exhibiting primary resistance to enzalutamide.

Impact of Long-term Adjuvant Hormonal Therapy in High-dose IMRT for Unfavorable Locally Advanced Prostate Cancer.

BACKGROUND/AIM: The aim of this study was to evaluate the benefit of adding long-term adjuvant hormonal therapy to high-dose intensity-modulated radiation therapy for locally advanced prostate cancer patients with multiple unfavorable risks. PATIENTS AND METHODS: All cT3-4N0M0 prostate cancer patients with Gleason score 8-10 and prostate-specific antigen ≥30 ng/ml who received intensity-modulated radiation therapy to the prostate and seminal vesicle alone (78 Gy in 39 fractions) between September 2000 and June 2017 at our institution were analyzed retrospectively. All patients received short-term neoadjuvant hormonal therapy. Before May 2011, salvage hormonal therapy was initiated when prostate-specific antigen levels exceeded 4.0 ng/ml (early salvage hormonal therapy cohort). In June 2011, 2-year adjuvant hormonal therapy was added (adjuvant hormonal therapy cohort). Clinical outcomes were retrospectively compared using the log-rank test. RESULTS: In total, 88 patients (44 in both cohorts) were analyzed. Median follow-up periods were 10.9 and 6.1 years in early salvage hormonal therapy and adjuvant hormonal therapy cohorts, respectively. No significant difference in overall survival rates was observed (p=0.58). Disease controls were significantly better in the adjuvant hormonal therapy cohort: 95.5 versus 73.6% for castration-resistant prostate cancer-free rate (p=0.04), and 73.6 versus 34.1% for biochemical failure-free rate (p<0.001), both at 8 years, respectively. CONCLUSION: Among locally advanced prostate cancer patients with multiple unfavorable risks, adding long-term adjuvant hormonal therapy to high-dose intensity-modulated radiation therapy resulted in significantly better disease control than short-term hormonal therapy, even when salvaged early after biochemical failure.

Osteoblast-derived extracellular vesicles exert osteoblastic and tumor-suppressive functions via SERPINA3 and LCN2 in prostate cancer.

Clinically, the osteolytic phenotype is rare in prostate cancer (PCa), and the prognosis is generally worse than that of the osteoblastic phenotype. Osteoblastic prostate cancer (BPCa) is a major type of bone metastasis. Several factors responsible for osteogenesis have been identified, but the molecular mechanism of osteoblastic bone metastasis in PCa is not fully understood. Here, we show the osteogenic and tumor-suppressive roles of SERPINA3 and LCN2 in BPCa. In a co-culture of osteoblasts (OBs) and BPCa cells, SERPINA3 and LCN2 were remarkably upregulated in BPCa via OB-derived extracellular vesicles, while they were not in the co-culture of OBs and osteolytic prostate cancer (LPCa) cells. In both the co-culture system and mouse xenograft experiments with intracaudal injection, enhanced expression of SERPINA3 and LCN2 in PCa led to osteogenesis. Additionally, the addition of SERPINA3 and LCN2 to BPCa cells significantly suppressed the proliferative potential. Retrospective analysis also confirmed that high expression levels of SERPINA3 and LCN2 were significantly correlated with a better prognosis. Our results may partially explain how osteoblastic bone metastasis develops and why the prognosis for BPCa is relatively better than that for LPCa.

TFEB-translocated and -amplified renal cell carcinoma with VEGFA co-amplification: A case of long-term control by multimodal therapy including a vascular endothelial growth factor-receptor inhibitor.

Introduction: Renal cell carcinoma with TFEB amplification is rare and reportedly aggressive. We herein report a case of renal cell carcinoma with TFEB translocation and amplification in which long-term control was achieved by multimodal therapy including a vascular endothelial growth factor -receptor inhibitor. Case presentation: A 70-year-old man was referred to our institution for the treatment of renal cell carcinoma with multinodal metastases. Open nephrectomy and lymph node dissection were performed. Immunohistochemistry for transcription factor EB was positive, and fluorescent in situ hybridization revealed TFEB rearrangement and amplification. The diagnosis was TFEB-translocated and -amplified renal cell carcinoma. VEGFA amplification was also demonstrated by fluorescent in situ hybridization. The residual and recurrent tumors were treated and controlled for 52 months by vascular endothelial growth factor-receptor target therapy, radiation therapy, and additional surgery. Conclusion: A good long-term response to anti-vascular endothelial growth factor drug therapy may be due to VEGFA amplification and subsequent vascular endothelial growth factor overexpression.

Novel Manifestation of Retinal Hemangioblastomas Detected by OCT Angiography in von Hippel-Lindau Disease.

PURPOSE: To elucidate the clinical characteristics of atypical retinal vascular proliferation in patients with von Hippel-Lindau (VHL) disease using OCT angiography (OCTA). DESIGN: Prospective, observational study. PARTICIPANTS: Fifty-seven consecutive patients with a diagnosis of VHL disease who visited Kyoto University Hospital between January 2019 and March 2022. METHODS: Retinal hemangioblastomas (RHs) were assessed using multimodal imaging including OCTA. Retinal hemangioblastomas were classified into 2 phenotypes: nodular and flat. Nodular RHs were defined as typical RHs that were globular, well-circumscribed tumors, often accompanied with dilated feeder arterioles and draining venules. Flat RHs lacked a protruded red or colored mass, had variable and indistinct borders, and were not accompanied with feeder and draining vessels. MAIN OUTCOME MEASURES: The prevalence, distribution, and description of atypical flat RHs. RESULTS: Among 57 consecutive patients with VHL disease, 37 patients (64.9%) showed RHs in at least 1 eye. Bilateral RHs were seen in 23 patients (62.2%). Among 58 eyes of 37 patients with RHs, typical nodular RHs were detected in 54 eyes. Nodular RHs were seen mainly in the peripheral retina and occasionally in the peripapillary region, and they showed exudative changes in some cases. Flat RHs were detected in 7 eyes (12.1%). Four eyes showed only flat RHs, and 3 eyes showed both types in the same eye. Most flat RHs appeared as retinal hemorrhages or faint flat abnormal retinal vessels in the inner retina on the fundus examination, often within the macula area or peripapillary. In all eyes with flat RHs, OCTA showed abundant blood flow in the lesions. OCT revealed that flat RHs were seen mainly between the retinal nerve fiber layer and the ganglion cell layer, and occasionally within the inner nuclear layer. During a mean follow-up period of 20.4 ± 15.0 months, no flat RHs accompanied exudative change, tractional retinal detachment, or progression in size. CONCLUSIONS: Patients with VHL disease can demonstrate 2 distinct types of RHs: the classic nodular type and an atypical flat type. OCT angiography can be useful in improving the detection of atypical flat RHs, which can be difficult to detect clinically. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Development of drugs targeting hypoxia-inducible factor against tumor cells with VHL mutation: Story of 127 years.

Intratumoral hypoxia is associated with tumor progression and therapeutic resistance. The VHL tumor suppressor gene was identified in 1993, and later studies revealed that the gene product pVHL interacts with other proteins to form the VBC complex. The VBC complex functions as an E3 ubiquitin ligase and regulates the abundance of the α-subunit of the transcription factor hypoxia-inducible factor (HIF). Hypoxia-inducible factor regulates thousands of genes required for cells to adapt and survive in hypoxic conditions, and thus pVHL plays a major role in oxygen-sensing pathways. Patients with von Hippel-Lindau (VHL) disease, harboring a germline mutation of the VHL gene, develop renal cell carcinomas and a series of tumors showing hypervascular phenotypes. The extensive findings that have clarified the function of VHL have contributed to the development of novel first-in-human drugs, including belzutifan, a HIF-2α inhibitor. The 2019 Nobel Prize in Physiology or Medicine was awarded to Dr. William G. Kaelin Jr., Dr. Peter J. Ratcliffe, and Dr. Gregg L. Semenza as researchers contributing to clarifying the mechanism of the oxygen-sensing pathway of cells. The first report of VHL disease was in 1894, meaning the development of a specific drug for this disease took almost 125 years. In this article, we describe how researchers and clinician scientists successfully clarified the function of VHL and achieved a preclinical proof of concept to apply for clinical trials, key requirements for drug development.

Comparison of therapeutic features and oncologic outcome in patients with pN1 prostate cancer among robot-assisted, laparoscopic, or open radical prostatectomy.

OBJECTIVES: To compare the therapeutic features and oncological outcomes of robot-assisted radical prostatectomy (RARP) with those of open radical prostatectomy (ORP) or laparoscopic radical prostatectomy (LRP) in lymph node (LN) positive prostate cancer patients in a retrospective observational multi-institutional study. PATIENTS AND METHODS: We evaluated the clinical results of 561 patients across 33 institutions who underwent RARP, LRP, or ORP and who were diagnosed with LN-positive prostate cancer during RP with pelvic LN dissection (PLND). We determined the following survival outcomes: metastasis-free survival, overall survival, cancer-specific survival, and biochemical recurrence-free survival. The Kaplan-Meier method, log-rank test, and Cox proportional hazards regression model were used to evaluate the effect of treatment on oncological outcomes. Statistical significance was set at P < 0.05. RESULTS: There was no significant difference for any of the survival outcomes between the three surgical groups. However, RARP achieved a greater LN yield compared to that of ORP or LRP. When the extent of PLND was limited to the obturator LNs, the number of removed LNs (RLNs) was comparable between the three surgical groups. However, higher numbers of RLNs were achieved with RARP compared to the number of RLNs with ORP (P < 0.001) when PLND was extended to the external and/or internal iliac LNs. CONCLUSION: RARP, LRP, and ORP provided equal surgical outcomes for pN1 prostate cancer, and the prognosis was relatively good for all procedures. Increased numbers of RLNs may not necessarily affect the oncological outcome.

Circulating microRNA profiling for prediction of oncological outcomes in prostate cancer patients following radical prostatectomy.

BACKGROUND: Although radical prostatectomy is associated with good long-term oncological outcomes, approximately 30% of patients present biochemical recurrence, whereupon salvage treatments are required. Identification of novel molecular biomarkers to predict cancer behavior is clinically important. Here, we developed a novel microRNA (miRNA)-based prognostic model for patients who underwent radical prostatectomy. METHODS: We retrospectively investigated the clinical records of 295 patients who underwent radical prostatectomy between 2009 and 2017. We randomly assigned these cases into training or validation sets. The prognostic model was constructed using Fisher linear discriminant analysis in the training set, and we evaluated its performance in the validation set. RESULTS: Overall, 72 patients had biochemical recurrence. A prediction model was constructed using a combination of three miRNAs (miR-3147, miR-4513, and miR-4728-5p) and two pathological factors (pathological T stage and Gleason score). In the validation set, the predictive performance of the model was confirmed to be accurate (area under the receiver operating characteristic curve: 0.80; sensitivity: 0.78; specificity: 0.76). Additionally, Kaplan-Meier analysis revealed that the patients with a low prediction index had significantly longer recurrence-free survival than those with a high index (p < 0.001). CONCLUSIONS: Circulating miRNA profiles can provide information to predict recurrence after prostatectomy. Our model may be helpful for physicians to decide follow-up strategies for patients.

[A Case of Metastatic Adrenal Tumor with Liver Infiltration which was Successfully Resected by Laparoscopic Surgery Using Both Intraperitoneal and Retroperitoneal Approaches].

We report a case of metastatic adrenal tumor with liver invasion which was successfully resected by laparoscopic surgery using both intraperitoneal and retroperitoneal approaches. A man in his 70s was diagnosed with lung adenocarcinoma with mediastinal and supraclavicular nodes involvement accompanied with multiple brain metastases (cT1bN3M1c). After 4 courses of systemic chemotherapy (cisplatin + pemetrexed) and the radiation therapy to the brain metastases, tumor regression was observed in the primary tumor as well as all the metastatic lesions. After 13 months, a solitary metastasis developed to the right adrenal gland without progression of the primary and metastatic tumors. Tumor reduction was observed in the adrenal gland after the administration of pembrolizumab. However, the metastatic tumor eventually progressed and imaging studies revealed that the right adrenal metastasis invaded to the liver. Importantly, neither progression of the pre-existing tumors nor new metastasis was identified. Based on these findings, laparoscopic adrenalectomy and partial hepatectomy were performed using both intraperitoneal and retroperitoneal approaches. No recurrence was observed six months after the surgery.

HER2 G776S mutation promotes oncogenic potential in colorectal cancer cells when accompanied by loss of APC function.

Clinical cancer genome sequencing detects oncogenic variants that are potential targets for cancer treatment, but it also detects variants of unknown significance. These variants may interact with each other to influence tumor pathophysiology, however, such interactions have not been fully elucidated. Additionally, the effect of target therapy for those variants also unclarified. In this study, we investigated the biological functions of a HER2 mutation (G776S mutation) of unknown pathological significance, which was detected together with APC mutation by cancer genome sequencing of samples from a colorectal cancer (CRC) patient. Transfection of the HER2 G776S mutation alone slightly increased the kinase activity and phosphorylation of HER2 protein, but did not activate HER2 downstream signaling or alter the cell phenotype. On the other hand, the HER2 G776S mutation was shown to have strong oncogenic potential when loss of APC function was accompanied. We revealed that loss of APC function increased Wnt pathway activity but also increased RAS-GTP, which increased ERK phosphorylation triggered by HER2 G776S transfection. In addition, afatinib, a pan-HER tyrosine kinase inhibitor, suppressed tumor growth in xenografts derived from HER2 G776S-transfected CRC cells. These findings suggest that this HER2 mutation in CRC may be a potential therapeutic target.

The clinical significance of perioperative inflammatory index as a prognostic factor for patients with retroperitoneal soft tissue sarcoma.

BACKGROUND: The prognostic factors of retroperitoneal soft tissue sarcoma (STS) have been explored but not yet certain. This study evaluated the prognostic impact of various preoperative clinical parameters and inflammatory indices in primary STS, with a particular focus on the transition of inflammatory index before and after tumor resection in de-differentiated liposarcoma (DD-LPS). METHODS: The clinical data of 113 patients with primary retroperitoneal STS receiving tumor resection were reviewed. Six variables (neutrophils, platelets, C-reactive protein (CRP), lymphocytes, albumin, and hemoglobin) in the blood samples were measured and nine inflammatory indices (neutrophil-lymphocyte ratio (NLR), CRP-lymphocyte ratio (CLR), platelet-lymphocyte ratio (PLR), neutrophil-albumin ratio (NAR), CRP-albumin ratio (CAR), platelet-albumin ratio (PAR), HALP (hemoglobin, albumin, lymphocyte and platelet), prognostic nutrition index (PNI), and modified Glasgow Prognostic Score (mGPS)) were calculated. The prognostic value of the indices was analyzed by univariate and multivariate analyses. RESULTS: Elevated NLR, CLR, PLR, NAR, CAR, PAR, and mGPS were associated with a worse overall survival (p = 0.0124, 0.0011, 0.049, 0.0047, 0.0085, 0.0332, and 0.0086, respectively) in univariate analysis. Multivariate analysis showed that elevated CLR and DD-LPS were associated with poor overall survival (p = 0.0267 and 0.0218, respectively) in all retroperitoneal STS. In DD-LPD, patients with preoperative high CLR, whose postoperative CLR was normalized, demonstrated a favorable survival rate similar to those with preoperative low CLR. CONCLUSIONS: Elevated CLR before surgery as well as DD-LPS were poor prognostic markers for overall survival in primary retroperitoneal STS. Perioperative CLR normalization may be related to a favorable prognosis in DD-LPS.

Serum microRNA as liquid biopsy biomarker for the prediction of oncological outcomes in patients with bladder cancer.

OBJECTIVES: Radical cystectomy is the gold-standard treatment for muscle-invasive bladder cancer and aggressive non-muscle-invasive bladder cancer. To enhance clinical decision-making regarding patients with bladder cancer who underwent radical cystectomy, a recurrence prediction biomarker with high accuracy is urgently needed. In this study, we developed a model for the prediction of bladder cancer recurrence after radical cystectomy by combining serum microRNA and a pathological factor. METHODS: We retrospectively analyzed the clinical records of 81 patients with bladder cancer who underwent radical cystectomy between 2008 and 2016. The dataset was divided into two, and Fisher linear discriminant analysis was used to construct a prognostic model for future recurrence in the training set (n = 41). The performance of the model was evaluated in the validation set (n = 40). RESULTS: Thirty patients had recurrence after having undergone radical cystectomy. A prognostic model for recurrence was constructed by combining a pathological factor (i.e. positive pathological lymph node status) and three microRNAs (miR-23a-3p, miR-3679-3p, and miR-3195). The model showed a sensitivity of 0.87, a specificity of 0.80, and an area under the receiver operating characteristic curve of 0.88 (0.77-0.98) in the validation set. Furthermore, Kaplan-Meier analysis revealed that patients with a low prediction index have significantly longer overall survival than patients with a high prediction index (P = 0.041). CONCLUSION: A combination of serum microRNA profiles and lymph node statuses is useful for the prediction of oncological outcomes after radical cystectomy in patients with bladder cancer.

Prevalence of Germline Variants in a Large Cohort of Japanese Patients with Pheochromocytoma and/or Paraganglioma.

The high incidence of germline variants in pheochromocytoma and paraganglioma (PPGL) has been reported mainly in Europe, but not among Japanese populations in Asia. We aimed to study the prevalence of germline variants in Japanese PPGL patients and the genotype-phenotype correlation. We examined 370 PPGL probands, including 43 patients with family history and/or syndromic presentation and 327 patients with apparently sporadic (AS) presentation. Clinical data and blood samples were collected, and the seven major susceptibility genes (MAX, SDHB, SDHC, SDHD, TMEM127, VHL, and RET) were tested using Sanger sequencing. Overall, 120/370 (32.4%) patients had pathogenic or likely pathogenic variants, with 81/327 (24.8%) in AS presentation. SDHB was the most frequently mutated gene (57, 15.4%), followed by SDHD (27, 7.3%), and VHL (18, 4.9%). The incidence of metastatic PPGL was high in SDHB carriers (21/57, 36.8%). A few unique recurrent variants (SDHB c.137G>A and SDHB c.470delT) were detected in this Japanese cohort, highlighting ethnic differences. In summary, almost a quarter of patients with apparently sporadic PPGL in Japan harboured germline variants of the targeted genes. This study reinforces the recommendation in Western guidelines to perform genetic testing for PPGL and genotype-based clinical decision-making in the Japanese population.

Detection of von Hippel-Lindau gene mutation in circulating cell-free DNA for clear cell renal cell carcinoma.

The therapeutic landscape of metastatic clear cell renal cell carcinoma (ccRCC) has rapidly expanded, and there is an urgent need to develop noninvasive biomarkers that can select an optimal therapy or evaluate the response in real time. To evaluate the clinical utility of circulating tumor DNA (ctDNA) analysis in ccRCC, we established a highly sensitive assay to detect mutations in von Hippel-Lindau gene (VHL) using a combination of digital PCR and multiplex PCR-based targeted sequencing. The unique assay could detect VHL mutations with a variant allele frequency (VAF) <1.0%. Further, we profiled the mutation status of VHL in 76 cell-free DNA (cfDNA) and 50 tumor tissues from 56 patients with ccRCC using the assay. Thirteen VHL mutations were identified in cfDNA from 12 (21.4%) patients with a median VAF of 0.78% (range, 0.13%-4.20%). Of the 28 patients with VHL mutations in matched tumor tissues, eight (28.6%) also had VHL mutation in cfDNA with a median VAF of 0.47% (range, 0.13%-2.88%). In serial ctDNA analysis from one patient, we confirmed that the VAF of VHL mutation changed consistent with tumor size by radiographic imaging during systemic treatment. In conclusion, VHL mutation in cfDNA was detected only in a small number of patients even using the highly sensitive assay; nevertheless, we showed the potential of ctDNA analysis as a novel biomarker in ccRCC.

Functional and genomic characterization of patient-derived xenograft model to study the adaptation to mTORC1 inhibitor in clear cell renal cell carcinoma.

Resistance to the mechanistic target of rapamycin (mTOR) inhibitors, which are a standard treatment for advanced clear cell renal cell carcinoma (ccRCC), eventually develops in most cases. In this study, we established a patient-derived xenograft (PDX) model which acquired resistance to the mTOR inhibitor temsirolimus, and explored the underlying mechanisms of resistance acquisition. Temsirolimus was administered to PDX model mice, and one cohort of PDX models acquired resistance after repeated passages. PDX tumors were genetically analyzed by whole-exome sequencing and detected several genetic alterations specific to resistant tumors. Among them, mutations in ANKRD12 and DNMT1 were already identified in the early passage of a resistant PDX model, and we focused on a DNMT1 mutation as a potential candidate for developing the resistant phenotype. While DNMT1 expression in temsirolimus-resistant tumors was comparable with the control tumors, DNMT enzyme activity was decreased in resistant tumors compared with controls. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9-mediated heterozygous knockdown of DNMT1 in the temsirolimus-sensitive ccRCC (786-O) cell line was shown to result in a temsirolimus-resistant phenotype in vitro and in vivo. Integrated gene profiles using methylation and microarray analyses of PDX tumors suggested a global shift for the hypomethylation status including promotor regions, and showed the upregulation of several molecules that regulate the mTOR pathway in temsirolimus-resistant tumors. Present study showed the feasibility of PDX model to explore the mechanisms of mTOR resistance acquisition and suggested that genetic alterations, including that of DNMT1, which alter the methylation status in cancer cells, are one of the potential mechanisms of developing resistance to temsirolimus.

Clinical significance of TP53 variants as possible secondary findings in tumor-only next-generation sequencing.

In tumor-only next-generation sequencing (NGS), identified variants have the potential to be secondary findings (SFs), but they require verification through additional germline testing. In the present study, 194 patients with advanced cancer who underwent tumor-only NGS between April 2015 and March 2018 were enrolled, and the incidences of possible and true SFs were evaluated. Among them, 120 patients (61.9%) harbored at least one possible SF. TP53 was the most frequent gene in which 97 variants were found in 91 patients (49.5%). Nine patients provided informed consent to undergo additional germline testing, and a total of 14 variants (BRCA1, n = 1; BRCA2, n = 2; PTEN, n = 2; RB1, n = 1; SMAD4, n = 1; STK11, n = 1; TP53, n = 6) were analyzed. Three variants (BRCA1, n = 1; BRCA2, n = 2) were confirmed to be SFs, whereas TP53 variants were confirmed to be somatic variants. To confirm the low prevalence of SFs in TP53, we analyzed 24 patients with TP53 variants who underwent a paired tumor-normal NGS assay. As expected, all TP53 variants were confirmed to be somatic variants. A total of 30 patients were tested for germline variants in TP53, but none of them resulted in true SFs, suggesting the low prevalence of SFs in this gene. Therefore, the significance of additional germline testing for TP53 variants appears to be relatively low in daily clinical practice using a tumor-only NGS assay, unless patients have any relevant medical or family history.