RC48-Antibody-Drug Conjugate in Metastatic Urothelial Carcinoma: A Multicenter Real-World Study in China.

OBJECTIVES: RC48 is an antibody-drug conjugate (ADC) that targets HER2. In China, RC48 is approved for patients with HER-2-positive metastatic urothelial carcinoma (mUC) who have failed at least platinum-based chemotherapy. This study aimed to evaluate RC48 for mUC in a cohort of real-world patients. MATERIALS AND METHODS: We retrospectively collected data from 103 mUC patients from 12 centers between July 2021 and August 2023 in China. RC48 alone or with immunotherapy was administered until disease progression, intolerable toxicity, death, or other reasons. The objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and incidence of treatment-related adverse events (TRAEs) were evaluated. RESULTS: The median age of the patients was 68 years, and 68.0% were men. Twenty-nine (28.2%) patients received RC48 alone; 73 (70.9%) received RC48 combination therapy. The response rates were as follows: complete response in 2 (1.9%) patients, partial response in 50 (48.5%) patients, stable disease in 30 (29.1%) patients. The ORR was 50.5%. In patients with ≥80 years, Eastern Cooperative Oncology Group (ECOG) performance status ≥2 and creatinine clearance rate (CCr) <30 mL/min, the ORR was 75%, 48.6%, and 40.0%, respectively. The median PFS was 6 (3.9-8.1) months, and the median OS was not reached. The most reported TRAEs were peripheral sensory neuropathy (53.4%), alopecia (42.7%), asthenia (38.8%), decreased appetite (35.9%) and weight loss (35.9%) and TRAE did not increase in patients with poor condition or impaired renal function. CONCLUSION: Administration of RC48 for real-world patients is both effective and safe. mUC patients can benefit from RC48-based therapy, regardless of their poor condition or impaired renal function.

Study of the influence of universal gearing of steering system on vehicle handling stability.

The handling stability of a vehicle is a crucial performance aspect. In this study, the focus is on investigating the impact of the universal gearing of the steering shaft on the handling stability of the vehicle. The research involves a theoretical analysis of how the structural parameters of universal gearing affect the handling stability of the vehicle, which is then validated through a series of simulation experiments including swept-sine steering input simulation, constant radius cornering simulation, and cornering with steer release. Evaluation is based on objective indices such as the steering wheel angle, yaw rate, and lateral acceleration. Moreover, the trends of these indices with respect to the phase angle and initial angle of universal gearing are determined. The findings reveal that the steering ratio of the vehicle varies significantly for varying phase angle and initial angle, resulting in different handling performance. The relationship between the phase angle and fluctuation magnitude of steering ratio is particularly noteworthy, while the impact of initial angle is primarily on the phase of steering ratio. Furthermore, within a certain range, changing the structural parameters of the universal gearing has the potential to enhance the handling performance of the vehicle.

Diagnosis and treatment of primary seminoma of the prostate: A case report and review of literature.

BACKGROUND: Primary seminoma of the prostate (PSP) is a rare type of extragonadal germ cell tumour that is easily misdiagnosed, owing to the lack of specific clinical features. It is therefore necessary for clinicians to work toward improving the accuracy of PSP diagnosis. CASE SUMMARY: A 59-year-old male patient presenting with acute urinary retention was admitted to a local hospital. A misdiagnosis of benign prostatic hyperplasia led to an improper prostatectomy. Histopathology revealed PSP invading the bladder neck and bilateral seminal vesicles. Further radiotherapy treatment for the local lesion was performed, and the patient had a disease-free survival period of 96 mo. This case was analysed along with 13 other cases of PSP identified from the literature. Only four of the cases (28.6%) were initially confirmed by prostate biopsy. In these cases, imaging examinations showed an enlarged prostate (range 6-11 cm) involving the bladder neck (13/14). Of the 14 total cases, 11 (78.6%) presented typical pure seminoma cell features, staining strongly positive for placental alkaline phosphatase, CD117, and OCT4. The median age at diagnosis was 51 (range 27-59) years, and patients had a median progression-free survival time of 48 (range 6-156) mo after treatment by cisplatin-based chemotherapy combined with surgery or radiotherapy. The remaining three were cases of mixed embryonal tumours with focal seminoma, which had clinical features similar to those of pure PSP, in addition that they also had elevated serum alpha-fetoprotein, beta-human chorionic gonadotropin, and lactose dehydrogenase. CONCLUSION: PSP should be considered in patients younger than 60 years with an enlarged prostate invading the bladder neck. Further prostate biopsies may aid in proper PSP diagnosis. Cisplatin-based chemotherapy is still the main primary therapy for PSP.

ß-secretase 1 overexpression by AAV-mediated gene delivery prevents retina degeneration in a mouse model of age-related macular degeneration.

We reported previously that ß-site amyloid precursor protein cleaving enzyme (BACE1) is strongly expressed in the normal retina and that BACE1-/- mice develop pathological phenotypes associated with age-related macular degeneration (AMD). BACE1 expression is increased within the neural retina and retinal pigment epithelium (RPE) in AMD donor eyes suggesting that increased BACE1 is compensatory. We observed that AAV-mediated BACE1 overexpression in the RPE was maintained up to 6 months after AAV1-BACE1 administration. No significant changes in normal mouse visual function or retinal morphology were observed with low-dose vector while the high-dose vector demonstrated some early pathology which regressed with time. No increase in ß-amyloid was observed. BACE1 overexpression in the RPE of the superoxide dismutase 2 knockdown (SOD2 KD) mouse, which exhibits an AMD-like phenotype, prevented loss of retinal function and retinal pathology, and this was sustained out to 6 months. Furthermore, BACE1 overexpression was able to inhibit oxidative stress, microglial changes, and loss of RPE tight junction integrity (all features of AMD) in SOD2 KD mice. In conclusion, BACE1 plays a key role in retina/RPE homeostasis, and BACE1 overexpression offers a novel therapeutic target in the treatment of AMD.

PRMT5 is a therapeutic target in choroidal neovascularization.

Ocular neovascular diseases including neovascular age-related macular degeneration (nvAMD) are widespread causes of blindness. Patients' non-responsiveness to currently used biologics that target vascular endothelial growth factor (VEGF) poses an unmet need for novel therapies. Here, we identify protein arginine methyltransferase 5 (PRMT5) as a novel therapeutic target for nvAMD. PRMT5 is a well-known epigenetic enzyme. We previously showed that PRMT5 methylates and activates a proangiogenic and proinflammatory transcription factor, the nuclear factor kappa B (NF-κB), which has a master role in tumor progression, notably in pancreatic ductal adenocarcinoma and colorectal cancer. We identified a potent and specific small molecule inhibitor of PRMT5, PR5-LL-CM01, that dampens the methylation and activation of NF-κB. Here for the first time, we assessed the antiangiogenic activity of PR5-LL-CM01 in ocular cells. Immunostaining of human nvAMD sections revealed that PRMT5 is highly expressed in the retinal pigment epithelium (RPE)/choroid where neovascularization occurs, while mouse eyes with laser induced choroidal neovascularization (L-CNV) showed PRMT5 is overexpressed in the retinal ganglion cell layer and in the RPE/choroid. Importantly, inhibition of PRMT5 by PR5-LL-CM01 or shRNA knockdown of PRMT5 in human retinal endothelial cells (HRECs) and induced pluripotent stem cell (iPSC)-derived choroidal endothelial cells (iCEC2) reduced NF-κB activity and the expression of its target genes, such as tumor necrosis factor α (TNF-α) and VEGF-A. In addition to inhibiting angiogenic properties of proliferation and tube formation, PR5-LL-CM01 blocked cell cycle progression at G1/S-phase in a dose-dependent manner in these cells. Thus, we provide the first evidence that inhibition of PRMT5 impedes angiogenesis in ocular endothelial cells, suggesting PRMT5 as a potential therapeutic target to ameliorate ocular neovascularization.

Decreased Expression of Soluble Epoxide Hydrolase Suppresses Murine Choroidal Neovascularization.

Neovascular or "wet" age-related macular degeneration (nAMD) is a leading cause of blindness among older adults. Choroidal neovascularization (CNV) is a major pathological feature of nAMD, in which abnormal new blood vessel growth from the choroid leads to irreversible vision loss. There is a critical need to develop novel therapeutic strategies to address limitations of the current anti-vascular endothelial growth factor biologics. Previously, we identified soluble epoxide hydrolase (sEH) as a possible therapeutic target for CNV through a forward chemical genetic approach. The purpose of this study was to validate sEH as a target by examining retinal expression of sEH protein and mRNA by immunohistochemistry and RNAscope in situ hybridization, respectively, and to assess the efficacy of an adeno-associated virus (AAV) vector designed to knock down the sEH gene, Ephx2, in the murine laser-induced (L-) CNV model. nAMD patient postmortem eye tissue and murine L-CNV showed overexpression of sEH in photoreceptors and retinal pigment epithelial cells. Ephx2 knockdown significantly reduced CNV and normalized mRNA expression levels of CNV-related inflammatory markers. Thus, this study further establishes sEH as a promising therapeutic target against CNV associated with nAMD.

Sulforaphane recovers cone function in an Nrf2-dependent manner in middle-aged mice undergoing RPE oxidative stress.

Purpose: Sulforaphane (SFN) is an isothiocyanate derived from cruciferous vegetables that has therapeutic efficacy in numerous animal models of human disease, including mouse models of retinal degeneration. However, despite dozens of clinical trials, the compound remains to be tested as a clinical treatment for ocular disease. Numerous cellular activities of SFN have been identified, including the activation of Nrf2, a transcription factor that induces a battery of target gene products to neutralize oxidative and xenobiotic stresses. As Nrf2 expression and function reportedly decrease with aging, we tested whether the loss of the transcription factor limits the therapeutic efficacy of SFN against retinal degeneration. Methods: Six- to 8-month-old wild-type and Nrf2 knockout mice were treated with SFN beginning 1 month after ribozyme-mediated knockdown of superoxide dismutase 2 (SOD2) mRNA in the RPE. The impacts of MnSOD (the protein product of SOD2) knockdown and the efficacy of SFN were evaluated using a combination of electroretinography (ERG), spectral domain optical coherence tomography (SD-OCT), and postmortem histology. Results: SFN restored the ERG photopic b-wave suppressed by MnSOD loss in wild-type mice, but not in the Nrf2 knockout mice. In contrast, ERG scotopic a- and b-wave loss was not restored for either genotype. SFN significantly improved retinal thickness in the Nrf2 knockout mice with MnSOD knockdown, but this was not observed in the wild-type mice. In both genotypes, SFN treatment reduced morphological markers of RPE atrophy and degeneration, although these improvements did not correlate proportionally with functional recovery. Conclusions: These findings highlight the capacity of SFN to preserve cone function, as well as the potential challenges of using the compound as a standalone treatment for age-related retinal degeneration under conditions associated with reduced Nrf2 function.

[Clinical and genetic analysis of seven Chinese pedigrees affected with multiple endocrine neoplasia type 2A with cutaneous lichen amyloidosis].

OBJECTIVE: To explore the pathological characteristics and significance of RET proto-oncogene screening in multiple endocrine neoplasia type 2A (MEN2A) with cutaneous lichen amyloidosis (CLA). METHODS: Clinical data of 51 members from 7 unrelated pedigrees of MEN2A-CLA were collected. Systemic clinical investigations including biochemical testing, imaging examination, germline RET variant screening and histopathological examination were carried out. RESULTS: RET gene variants were detected in 28 patients with MEN2A (C634G/F/R/S/W and C611Y) including 12 males and 16 females, with the mean age of diagnosis being (41.1 ± 18.3) years old, which were consistent with their clinical manifestations. The incidence of medullary thyroid carcinoma (MTC), pheochromocytoma (PHEO), hyperparathyroidism (HPTH) and CLA among 28 MEN2A patients were 89.3%, 28.6%, 7.1% and 28.6%, respectively. Comparison of the incidence of MTC/PHEO/HPTH and CLA between C611Y and C634G/F/R/S/W, only PHEO and CLA in C611Y were lower than those in C634G/F/R/S/W (P < 0.05; P < 0.05). Among 8 patients with CLA, the male to female ratio was 2 : 6. The clinical features included pruritus in the interscapular region and presence of dry, thickened, scaly, brown pigment, clustered or desquamate-like plaques. The mean onset age of CLA [(18.4 ± 4.6) years] versus the mean age at diagnosis of CLA or MEN2A were significantly different (P < 0.001; P < 0.001). CONCLUSION: MEN2A-CLA may be the early clinical manifestation of MEN2A and most frequently occurred along with RET-C634 variant. To facilitate the recognition of MEN2A-CLA, to combine family investigation and screening of RET variant are helpful for early diagnosis and standardized treatment, which can improve the long-term outcome of MEN2A-specific tumors.

Clinical Benefit of Niraparib to TKI/mTORi-Resistance Metastatic ccRCC With BAP1-Frame Shift Mutation: Case Report and Literature Review.

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cancer. The top four mutant genes affecting the occurrence and progression of ccRCC are VHL, PBRM1, BAP1, and SETD2, respectively. Tyrosine kinase/mammalian target of rapamycin inhibitors (TKI/mTORis) with or without immunotherapy are the standard and effective therapy to metastatic ccRCC. Once TKI/mTORis fail to ccRCC, there is still a lack of other effective therapies. In this study, we reported a case in which a metastatic ccRCC patient (T2aN1M1) presented resistance after a 28-month treatment by sorafenib-axitinib-everolimus (TKI-TKI-mTORi). Subsequently, a frame shift pathogenic mutation, c.799_800del (p.Q267fs) in the exon10 of BAP1 in ccRCC, was revealed by targeted sequencing. Oral administration of nilapanib (PARP inhibitor) was further given, which may provide a new therapy for TKI/mTORi-resistance metastatic ccRCC. Fortunately, a partial response has been achieved and lasted for 5 months. Since the frequency of BAP1 mutations in ccRCC patients was approximately 10%-20%, as reported previously, we also tried to explore the potential mechanisms benefitting from the nilapanib. Moreover, the literature concerning BAP1 mutation and associated cancers including ccRCC is reviewed.

Impact of RET Screening on the Management of Multiple Endocrine Neoplasia Type 2A: 10 Years Experience and Follow-Up in Three Families.

BACKGROUND: Multiple endocrine neoplasia type 2A (MEN 2A) is mainly caused by germline RET codon C634 mutation and is characterized by Medullary Thyroid Carcinoma (MTC), pheochromocytoma (PHEO), and hyperparathyroidism (HPTH). The early diagnosis and initial normative treatment are helpful for the long-term outcome of MEN2A. METHODS: Three index cases and their 29 relatives from three families with MEN2A were included in this study. Genetic screening was performed on all participants. Demographic, clinical profiles, tumor histopathologic features, and follow-up records were systematically analyzed. RESULTS: In total, RET C634Y mutation was identified in 10 individuals (10/32, 31.3%). Among them, 5 presented with MTC symptoms, whereas the other 5 did not show apparent clinical manifestation, and all were subjected to thyroidectomy with varying neck dissection. Compared to individuals in the former, the latter benefited greatly from RET screening with significantly younger age at diagnosis of MTC and surgery (18.1 ± 13.8 years vs. 39.0 ± 14.1 years, P =0.045), and lessaggressive MTC behavior (size: 0.74 vs. 2.82 cm, P =0.026; LN+/resected: 20.0% vs. 100.0%, P =0.048) and also lower recurrence rate of MTC (20.0% vs. 100.0%, P =0.048). The PHEO was identified in 6 of the 10 carriers (60.0%), and all had undergone adrenal-sparing surgery. During the 10 years of follow-up, one (16.7%) developed recurrence of PHEO. CONCLUSION: Integrated RET screening, serum calcitonin, and plasma metanephrine/ normetanephrine levels can facilitate the early diagnosis and standardized MTC/PHEO surgery to improve the prognosis of MEN2A. Laparoscopic adrenal-sparing surgery prior to the bilateral total thyroidectomy is a preferred surgical approach for PHEO.

Simultaneous bilateral laparoscopic cortical-sparing adrenalectomy for bilateral pheochromocytomas in multiple endocrine neoplasia type 2.

Purpose: This study aimed to assess the feasibility of synchronous bilateral laparoscopic or open cortical-sparing adrenalectomy (SB-LCSA or SB-OCSA) for bilateral pheochromocytomas (bPHEOs) in multiple endocrine neoplasia type 2 (MEN2). Methods: Altogether, 31 patients (54.8% were women) were diagnosed with MEN2-related bPHEOs, and 29 of them underwent varying specific adrenalectomies. We systematically analyzed and evaluated their clinical profiles, mutation types, tumor histopathological features, and follow-up records. Results: All 31 patients with bPHEOs presented with RET-C634 (90.3%) and RET-M918T (9.7%) mutations, and the median age at initial presentation was 38 years (range, 23-78). bPHEOs were synchronous in 27 patients and metachronous in 4 (12.9%) patients. In total, 29 patients underwent initial cortical-sparing adrenalectomy (CSA) including 23 (79.3%) undergoing synchronous bilateral CSA (18 SB-LCSA and 5 SB-OCSA) and 6 (20.7%) undergoing metachronous CSA. SB-LCSA and synchronous surgery were associated with less bleeding volume and shorter length of hospital stay than SB-OCSA and metachronous surgery (all P's < 0.05). Corticosteroid replacement treatment was necessary for 14 patients (45.2%) after bilateral CSA. During a median follow-up period of 7 years (range, 1.8-23), three of these patients (10.3%) had a recurrent disease that required reoperation. Conclusion: SB-LCSA is feasible for treating synchronous bPHEOs and should be recommended as a prioritized surgical approach.

BACE1 Inhibition Increases Susceptibility to Oxidative Stress by Promoting Mitochondrial Damage.

BACE1 is a key enzyme facilitating the generation of neurotoxic ß-amyloid (Aß) peptide. However, given that BACE1 has multiple substrates we explored the importance of BACE1 in the maintenance of retinal pigment epithelial (RPE) cell homeostasis under oxidative stress. Inhibition of BACE1 reduced mitochondrial membrane potential, increased mitochondrial fragmentation, and increased cleaved caspase-3 expression in cells under oxidative stress. BACE1 inhibition also resulted in significantly lower levels of mitochondrial fusion proteins OPA1 and MFN1 suggesting a higher rate of mitochondrial fission while increasing the levels of mitophagic proteins Parkin and PINK1 and autophagosome numbers. In contrast, BACE2 had minimal effect on cellular response to oxidative stress. In summary, our results emphasize the importance of BACE1 in augmenting cellular defense against oxidative stress by protecting mitochondrial dynamics.

Supplemental nitrite increases choroidal neovascularization in mice.

Low doses of nitrite, close to physiological levels, increase blood flow in normal and ischemic tissues through a nitric oxide (NO) dependent mechanism. Given that nitrite therapy and dietary supplementation with vegetables high in nitrate (e.g. beets) are gaining popularity we decided to determine if low doses of nitrite impact the development of choroidal neovascularization (CNV), a key feature of wet age related macular degeneration (AMD). Sodium nitrite (at 50 mg/L, 150 mg/L, and 300 mg/L), nitrate (1 g/L) or water alone were provided in the drinking water of C57BL/6 J mice aged 2 or 12 months. Mice were allowed to drink ad libitum for 1 week at which time laser-induced choroidal neovascularization (L-CNV) was induced. The mice continued to drink the supplemented water ad libitum for a further 14 days at which point optical coherence tomography (OCT) was performed to determine the volume of the CNV lesion. Blood was drawn to determine nitrite and nitrate levels and eyes taken for histology. CNV volume was 2.86 × 107 µm3 (±0.4 × 107) in young mice on water alone but CNV volume more than doubled to >6.9 × 107 µm3 (±0.8 × 107) in mice receiving 300 mg/L nitrite or 7.34 × 107 µm3 (±1.4 × 107) in 1 g/L nitrate (p < 0.01). A similar trend was observed in older mice. CNV volume was 5.3 × 107 µm3 (±0.5 × 107) in older mice on water alone but CNV volume almost doubled to approximately 9.3 × 107 µm3 (±1.1 × 107) in mice receiving 300 mg/L nitrite or 8.7 × 107 µm3 (±0.9 × 107) 1 g/L nitrate (p < 0.01). Plasma nitrite levels were highest in young mice receiving 150 mg/L in the drinking water with no changes in plasma nitrate observed. In older mice, drinking water nitrite did not significantly change plasma nitrite, but plasma nitrate was increased. Plasma nitrate was elevated in both young and old mice provided with nitrate supplemented drinking water. Our data demonstrate that the CNV lesion is larger in older mice compared to young and that therapeutic levels of oral nitrite increase the volume of CNV lesions in both young and older mice. Therapeutic nitrite or nitrate supplementation should be used with caution in the elderly population prone to CNV.

Characterizing temporal and spatial recruitment of systemically administered RPE65-programmed bone marrow-derived cells to the retina in a mouse model of age-related macular degeneration.

PURPOSE: Previously, we reported that the intravenous injection of bone marrow-derived cells (BMDC) infected with lentivirus expressing the human RPE65 gene resulted in the programming of BMDC to promote visual recovery in a mouse model of age-related macular degeneration (AMD). The aim of this study was to characterize the spatial and temporal recruitment of these programmed BMDC to the retinal pigment epithelial (RPE) layer. METHODS: C57BL/6J female mice received a subretinal injection of AAV1-SOD2 ribozyme to knock down (KD) superoxide dismutase 2 (SOD2) and induce AMD-like pathology. BMDC were isolated from GFP+ mice and infected with a lentivirus expressing RPE65. One month after SOD2 KD, fifty thousand GFP+ RPE65-BMDC were injected in the mouse tail vein. Animals were terminated at different time points up to 60 min following cell administration, and localization of GFP+ cells was determined by fluorescence microscopy of neural retina and RPE flat mounts and tissue sections. RESULTS: GFP+ RPE65- BMDC were observed in SOD2 KD neural retina and RPE as early as 1 min following administration. With increasing time, the number of cells in the neural retina decreased, while those in the RPE increased. While the number of cells in peripheral and central retina remained similar at each time point, the number of BMDC recruited to the central RPE increased in a time-dependent manner up to a maximum by 60 min post administration. Immunohistochemistry of cross-sections of the RPE layer confirmed the incorporation of donor GFP+ BMDC into the RPE layer and that these GFP+ human RPE65 expressing cells co-localized with murine RPE65. No GFP+ cells were observed in the neural retina or RPE layer of normal uninjured control eyes. CONCLUSIONS: Our study shows that systemically administered GFP+ RPE65-BMDC can reach the retina within minutes and that the majority of these BMDC are recruited to the injured RPE layer by 60 min post injection.

Spatial and temporal VEGF receptor intracellular trafficking in microvascular and macrovascular endothelial cells.

The vascular endothelial growth factor receptors (VEGFRs) can shape the neovascular phenotype of vascular endothelial cells when translocated to the nucleus, however the spatial and temporal changes in the intracellular distribution and translocation of VEGFRs to the nucleus and the organelles involved in this process is unclear. This study reports the effect of exogenous VEGF on translocation of VEGFRs and organelles in micro- and macrovascular endothelial cells. We showed that VEGF is responsible for: a rapid and substantial nuclear translocation of VEGFRs; VEGFR1 and VEGFR2 exhibit distinct spatial, temporal and structural translocation characteristics both in vitro and in vivo and this determines the nuclear VEGFR1:VEGFR2 ratio which differs between microvascular and macrovascular cells; VEGFR2 nuclear translocation is associated with the endosomal pathway transporting the receptor from Golgi in microvascular endothelial cells; and an increase in the volume of intracellular organelles. In conclusion, the nuclear translocation of VEGFRs is both receptor and vessel (macro versus micro) dependent and the endosomal pathway plays a key role in the translocation of VEGFRs to the nucleus and the subsequent export to the lysosomal system. Modulating VEGF-mediated VEGFR1 and VEGFR2 intracellular transmigration pathways may offer an alternative for the development of new anti-angiogenic therapies.

Elevated basal serum levels of calcitonin and simultaneous surgery of MEN2A-specific tumors.

Multiple endocrine neoplasia type 2A (MEN2A) is a rare syndrome caused almost by germline RET mutation, and characterized by medullary thyroid carcinoma (MTC), in combination or not with pheochromocytoma (PHEO), hyperparathyroidism (HPTH), cutaneous lichen amyloidosis (CLA), and Hirschsprung's disease (HD). The basal serum calcitonin (Ctn)/carcinoembryonic antigen (CEA) levels are significantly correlated with the MTC stage. Metachronous surgery of MEN2A-specific tumors is a routine procedure. We aimed to explore the clinical significance of pro-gastrin-releasing peptide (proGRP) in MTC with elevated Ctn and simultaneous surgery of MEN2A-specific tumors. We retrospectively investigated 8 RET mutation carriers of 2 Chinese pedigrees with MEN2A. Clinical profiles, imaging examinations, preoperative and postoperative biochemical data, surgical procedures, and follow-up records were evaluated. Three patients showed levels of elevated Ctn but normal proGRP. Among them, one patient (FAIII-6) in Family A (one for RET C634R mutation), diagnosed with bilateral MTC, left PHEO, bilateral HPTH, and CLA, classified as MEN2A-related CLA subtype, underwent successfully simultaneous adrenal-sparing surgery (ASS), total thyroidectomy (TT), and parathyroidectomy, while TT of the other two patients (FBII-3 and FBIII-7) diagnosed with bilateral MTC in Family B (all for RET C618R mutation) were performed. Unexpectedly, the absence of neck lymph node MTC metastasis was indicated by histopathological examination. Postoperatively, all had consistently "undetectable" or normal levels of Ctn/CEA during follow-up. Patients with normal proGRP, despite high levels of Ctn, might have no regional lymph node MTC metastasis, and neck dissection should be avoided. Moreover, simultaneous surgery for coexistent PHEO and either MTC or HPTH is an approach of choice to use as an alternative treatment pattern. Recognition of MEN2A-related CLA and subsequently early screening of RET mutation may be favorable for timely management of MEN2A-specific tumors.

Spectrum of Germline RET variants identified by targeted sequencing and associated Multiple Endocrine Neoplasia type 2 susceptibility in China.

BACKGROUND: Germline RET mutations and variants are involved in development of multiple endocrine neoplasia type 2 (MEN2). The present study investigated a spectrum of RET variants, analyzed genotype-phenotype relationships, and evaluated their effect on the MEN2 phenotype in Han Chinese patients. METHODS: Targeted sequencing detected germline RET variants in 697 individuals, including 245 MEN2, 120 sporadic medullary thyroid cancer (MTC), and 15 pheochromocytoma (PHEO) patients and their 493 relatives. In silico analyses and classifications following ACMG-2015 were performed. Demographic, clinical variant types, and endocrine neoplasia molecular diagnosis records were also analyzed. RESULTS: Nineteen different RET mutations (18 point and 1 del/ins mutations) in 214 patients with MEN2A (97.7%) or MEN2B (2.3%) were found, of which exon 11/10 mutations accounted for 79% (169/214). Nineteen compound mutations were found in 31 patients with MEN2A. Twenty-three variants (18 single and 5 double base substitution/compound variants) non-classification were also found. Of these, 17 (3 of pathogenic, 10 of uncertain significance, 2 of likely benign and 2 as benign) were found in 31 patients with MTC/PHEO. The remaining 6 variants (4 of uncertain significance and 2 of likely benign) found in 8 carriers had no evidence of MEN2. The entire cohort showed MEN2A-related PHEO, all occurring in exons 11/10, particularly at C634. Kaplan-Meier curves showed age-dependent penetration rates of MTC and PHEO, and occurrence rates of PHEO in patients with exon 11 mutations were all higher than those within exon 10; these bilateral PHEO were always associated with exon 11 mutations (all P < 0.05). While patient offspring had PHEO, parents with MEN2A had none, the frequency was approximately 10%. Interestingly, at least 6.8% of families were adoptive. Also, 3 non-hotspot RET variants (R114H, T278N, and D489N) appeared with high frequency. Conversely, polymorphism S836S was absent. CONCLUSIONS: These data are largely consistent with current evidence-based recommendations in the clinical practice guidelines. Diversity of RET variants or carriers may involve a different natural disease course. Further large-scale targeted sequencing studies will serve as an accurate and cost-effective approach to investigating MEN2 genotype-phenotype correlations for discovery of rare or unknown variants of RET.

Molecular Diagnosis and Treatment of Multiple Endocrine Neoplasia Type 2B in Ethnic Han Chinese.

BACKGROUND: Multiple endocrine neoplasia type 2B (MEN 2B) is mainly caused by M918T RET germline mutation, and characterized by medullary thyroid carcinoma (MTC), pheochromocytoma (PHEO) and non-endocrine features. However, the diagnosis and treatment are usually delayed. METHODS: This study reports 5 Chinese pedigrees with 5 individuals harboring germline RETM918T, and systematically reviewed previous Chinese literature reported. RESULTS: All 5 patients initially presented MTC, but none had biochemically cured postoperatively. 2 also presented bilateral PHEO after adrenal-sparing surgery, 1 needed steroid replacement. Further, a total of 32 MEN 2B patients from literature were clustered with 28 available for analysis. 26 (92.8%) were diagnosed by endocrine-related symptoms; the remaining 2 (7.2%) due to RET testing and oral symptoms, respectively. 25 patients underwent thyroidectomy with/without neck lymph node dissection at the mean age of (23.3 ± 10.4) years. Histopathological examination revealed MTC (100%). Of them, 17 had definite TNM stage, with 1 in stage III and others in IV. Other information of MEN 2B-related symptoms included penetrance of PHEO (60.7%), constipation (32.1%), Hirschsprung disease (25%), alacrima (17.8%), mucosal ganglioneuroma (96.4%) and marfanoid habitus (71.4%). 19 patients were verified harboring RET-M918T (c.2753T>C), of whom 15 (78.9%) were de novo mutation. The other 9 were clinically diagnosed as MEN 2B. DISCUSSION & CONCLUSION: The initial diagnosis of MEN 2B is relatively later, and diagnosed by non-endocrine components is extremely lower. Recognition of MEN 2B and its non-endocrine-related components is still the utmost requirement for a Chinese physician. Combined RET screening and serum calcitonin detection can facilitate early diagnosis.

Multiple Endocrine Neoplasia Type 2B Associated Mixed Medullary and Follicular Thyroid Carcinoma in A Chinese Patient with RET M918T Germline Mutation.

BACKGROUND: Mixed medullary and follicular thyroid carcinoma (MMFC) displays heterogeneous morphological components and immunophenotypical features intermingled within the same lesion, which is rare and most described in the sporadic form. We report herein a Chinese patient with multiple endocrine neoplasia type 2B (MEN2B) harboring germline RET M918T and associated MMFC. METHODS: A case of a 39-year-old male patient with MEN2B presented palpable neck masses in both thyroid lobes (maximum sizes: left, 3.9 cm; right, 5.4 cm) and a definitive phenotype. Serum levels of calcitonin (Ctn; >2000pg/mL), carcinoembryonic antigen (CEA; 719.27ng/mL), and thyroglobulin (Tg; 98.54ng/mL) were high. Fine-needle aspiration cytology showed features positive for malignancy, suggesting the possibility of medullary thyroid carcinoma (MTC). Total thyroidectomy, along with extending bilateral neck lymph nodes dissection, and subsequently, genetics family screening were performed. RESULTS: The histopathological examination yielded a diagnosis of MMFC that showed immunohistochemical characteristic patterns of the component of MTC positive for Ctn and CEA, chromogranin A, and the follicular carcinoma components were positive for Tg. Lymph node metastasis was observed showing medullary tumoral cells positive for Ctn and follicular-like structures lacking tumor cells positive for Tg staining (T4bN1bM0). Genetics screening confirmed RET M918T (c.2753T>C) mutation manifested in the patient but was not detected in other family members. Follow up showed that the serum Ctn, CEA and Tg levels respectively dropped to 54.38pg/ml, 4.16ng/mL and 0.04ng/mL 16 months after the surgery. CONCLUSION: Particular and diverse patterns of MMFC should be recognized with immunostaining features. MMFC occurring in a patient with MEN2B harboring RET M918T may be unique biological behavior and the treatment is mostly radical surgery.