Metformin Overcomes the Consequences of NKX3.1 Loss to Suppress Prostate Cancer Progression.

BACKGROUND: The antidiabetic drug metformin has known anticancer effects related to its antioxidant activity; however, its clinical benefit for prostate cancer (PCa) has thus far been inconclusive. Here, we investigate whether the efficacy of metformin in PCa is related to the expression status of NKX3.1, a prostate-specific homeobox gene that functions in mitochondria to protect the prostate from aberrant oxidative stress. OBJECTIVE: To investigate the relationship of NKX3.1 expression and metformin efficacy in PCa. DESIGN, SETTING, AND PARTICIPANTS: Functional studies were performed in vivo and in vitro in genetically engineered mouse models and human LNCaP cells, and organotypic cultures having normal or reduced/absent levels of NKX3.1. Correlative studies were performed using two independent retrospective tissue microarray cohorts of radical prostatectomies and a retrospective cohort of prostate biopsies from patients on active surveillance. INTERVENTION: Metformin was administered before or after the induction of oxidative stress by treatment with paraquat. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Functional endpoints included analyses of histopathology, tumorigenicity, and mitochondrial function. Correlative endpoints include Kaplan-Meier curves and Cox proportional hazard regression models. RESULTS AND LIMITATIONS: Metformin reversed the adverse consequences of NKX3.1 deficiency following oxidative stress in vivo and in vitro, as evident by reduced tumorigenicity and restored mitochondrial function. Patients with low NKX3.1 expression showed a significant clinical benefit from taking metformin. CONCLUSIONS: Metformin can overcome the adverse consequences of NKX3.1 loss for PCa progression by protecting against oxidative stress and promoting normal mitochondrial function. These functional activities and clinical correlates were observed only with low NKX3.1 expression. Thus, the clinical benefit of metformin in PCa may depend on the status of NKX3.1 expression. PATIENT SUMMARY: Prostate cancer patients with low NKX3.1 are likely to benefit most from metformin treatment to delay disease progression in a precision interception paradigm.

Malakoplakia Presenting as a Lung Mass in a Lung Transplant Recipient: Case Report.

Lung nodules or masses due to a variety of malignant or benign conditions such as opportunistic infections are observed after lung transplant. Malakoplakia is a rare complication in immunocompromised patients. Here we describe the clinical course and management of a lung transplant recipient with pulmonary malakoplakia and provide a review of the literature. To our knowledge, this is the first report of a case of pulmonary malakoplakia due to Escherichia coli infection in a lung allograft.

The effect of tumor grade heterogeneity on recurrence in non-muscle invasive bladder cancer.

OBJECTIVE: To investigate the outcomes of mixed-grade non-muscle invasive bladder cancer (NMIBC) based on the degree of high-grade predominance. METHODS: We identified patients in our institutional database who had a transurethral resection of bladder tumor(s) for NMIBC. Tumors with mixed-grade features on pathology report were reanalyzed, assigned the percentage high-grade component, and stratified into ≤ 5% high-grade and > 5% high-grade groups. All others were classified as low-grade or high-grade NMIBC. Differences in recurrence-free survival were assessed by log-rank test. A multivariable Cox regression model was used to evaluate the impact of tumor grade on recurrence, controlling for tumor stage, size, multifocality, and intravesical therapy. RESULTS: Two hundred and twenty patients were followed for a median of 2 years; 127 (58%) had low-grade NMIBC, 66 (30%) had high-grade NMIBC, and 27 (12%) had mixed-grade NMIBC. Of the mixed-grade patients, 14 had a ≤ 5% high-grade component, and 13 had a > 5% high-grade component. Recurrence rates across all groups ranged from 42% to 79%. There was no significant difference in intravesical recurrence-free survival among the grade categories as assessed by log-rank test. On multivariable Cox regression analysis, grade category was not significantly associated with likelihood of recurrence. CONCLUSIONS: The prognosis of mixed-grade histology in NMIBC has not previously been well defined. Although grade category was not found to be an independent significant predictor of recurrence, the recurrence rate for mixed-grade tumors was quite high overall. Further studies are required to better understand appropriate risk stratification and treatment of mixed-grade NMIBC.

FOXP1 and NDRG1 act differentially as downstream effectors of RAD9-mediated prostate cancer cell functions.

Metastatic progression is the key feature of prostate cancer primarily responsible for mortality caused by this disease. RAD9 is an oncogene for prostate cancer, and the encoded protein enhances metastasis-related phenotypes. RAD9 is a transcription factor with a limited set of regulated target genes, but the complete list of downstream genes critical for prostate carcinogenesis is unknown. We used microarray gene expression profiling and chromatin immunoprecipitation in parallel to identify genes transcriptionally controlled by RAD9 that contribute to this cancer. We found expression of 44 genes altered in human prostate cancer DU145 cells when RAD9 is knocked down by siRNA, and all of them bind RAD9 at their genomic location. FOXP1 and NDRG1 were down regulated when RAD9 expression was reduced, and we evaluated them further. We demonstrate that reduced RAD9, FOXP1 or NDGR1 expression decreases cell proliferation, rapid migration, anchorage-independent growth, anoikis resistance, and aerobic glycolysis. Ectopic expression of FOXP1 or NDRG1 partially restored aerobic glycolysis to prostate cancer cells with reduced RAD9 abundance, but only FOXP1 significantly complemented the other deficiencies. We thus show, for the first time, that RAD9 regulates FOXP1 and NDRG1 expression, and they function differently as downstream effectors for RAD9-mediated prostate cancer cell activities.

NKX3.1 Localization to Mitochondria Suppresses Prostate Cancer Initiation.

Mitochondria provide the first line of defense against the tumor-promoting effects of oxidative stress. Here we show that the prostate-specific homeoprotein NKX3.1 suppresses prostate cancer initiation by protecting mitochondria from oxidative stress. Integrating analyses of genetically engineered mouse models, human prostate cancer cells, and human prostate cancer organotypic cultures, we find that, in response to oxidative stress, NKX3.1 is imported to mitochondria via the chaperone protein HSPA9, where it regulates transcription of mitochondrial-encoded electron transport chain (ETC) genes, thereby restoring oxidative phosphorylation and preventing cancer initiation. Germline polymorphisms of NKX3.1 associated with increased cancer risk fail to protect from oxidative stress or suppress tumorigenicity. Low expression levels of NKX3.1 combined with low expression of mitochondrial ETC genes are associated with adverse clinical outcome, whereas high levels of mitochondrial NKX3.1 protein are associated with favorable outcome. This work reveals an extranuclear role for NKX3.1 in suppression of prostate cancer by protecting mitochondrial function. SIGNIFICANCE: Our findings uncover a nonnuclear function for NKX3.1 that is a key mechanism for suppression of prostate cancer. Analyses of the expression levels and subcellular localization of NKX3.1 in patients at risk of cancer progression may improve risk assessment in a precision prevention paradigm, particularly for men undergoing active surveillance.See related commentary by Finch and Baena, p. 2132.This article is highlighted in the In This Issue feature, p. 2113.

Impact of COVID-19 pandemic on functioning of cytopathology laboratory: Experience and perspective from an academic centre in New York.

COVID-19 has extraordinarily impacted every facet of the health care facilities' operations. Various strategies and policies were implemented promptly to preserve resources, not only to provide medical care to the expected massive numbers of COVID-19 patients, but also to mitigate the contagion spread at the workplace to ensure safety of healthcare workers. All routine, non-essential medical services and procedures were ramped down and workers deemed non-essential were directed to work remotely from home to reduce the number of people at hospital premises and preserve much needed personal protective equipment that were in short supply at the outset of the pandemic. The laboratories did not remain unscathed and were under immense pressure to maintain workplace safety while being operational and provide best patient care with limited resources. In this paper, we share our experience and challenges that we faced in a cytopathology laboratory at a major academic centre in New York, USA during the peak of infection.

Bladder Preservation for Patients With Bladder Paragangliomas: Case Series and Review of the Literature.

Bladder paragangliomas are rare tumors, with no prospective studies or guidelines on the management of this disease. We present a case series of 6 patients managed with bladder preservation over a median follow-up period of 124 months. We also present a review of the recent literature on bladder paragangliomas. We aim to provide a timely synthesis of the recent evidence on bladder paragangliomas as changing paradigms necessitate individualized treatment.

A Phase I Trial of Intravesical Cabazitaxel, Gemcitabine and Cisplatin for the Treatment of Nonmuscle Invasive bacillus Calmette-Guérin Unresponsive or Recurrent/Relapsing Urothelial Carcinoma of the Bladder.

PURPOSE: For patients with bacillus Calmette-Guérin unresponsive or recurrent/relapsing nonmuscle invasive bladder cancer, multi-agent intravesical trials have been limited. In this study we investigate the safety of intravesical cabazitaxel, gemcitabine and cisplatin in the salvage setting. MATERIALS AND METHODS: This was a dose escalation, drug escalation trial for patients with bacillus Calmette-Guérin unresponsive or recurrent/relapsing nonmuscle invasive bladder cancer who declined or were ineligible for radical cystectomy. All patients underwent a 6-week induction regimen of sequentially administered cabazitaxel, gemcitabine and cisplatin. Complete response was defined as no cancer on post-induction transurethral bladder tumor resection and negative urine cytology, while partial response allowed for positive cytology. Responders continued with maintenance cabazitaxel and gemcitabine monthly for the first year and bimonthly for the second year. RESULTS: A total of 18 patients were enrolled. Mean age was 71 years, median followup was 27.8 months (range 16.3 to 46.9) and mean number of previous rounds of intravesical therapies before trial enrollment was 3.7. Nine patients (50%) had received intravesical chemotherapy after bacillus Calmette-Guérin and 7 (39%) were previously treated in a phase I clinical trial setting. At enrollment 6 (33%) subjects had T1 disease and 13 (72%) had carcinoma in situ. There were no dose limiting toxicities. Initial partial and complete response rates were 94% and 89%, respectively. At 1 year recurrence-free survival was 0.83 (range 0.57 to 0.94) and at 2 years estimated recurrence-free survival was 0.64 (0.32 to 0.84). CONCLUSIONS: In this high risk and highly pretreated cohort of bacillus Calmette-Guérin unresponsive or recurrent/relapsing nonmuscle invasive bladder cancer cases combination intravesical cabazitaxel, gemcitabine and cisplatin was a well tolerated and potentially effective regimen.

Targeting MEK5 impairs nonhomologous end-joining repair and sensitizes prostate cancer to DNA damaging agents.

Radiotherapy is commonly used to treat a variety of solid human tumors, including localized prostate cancer. However, treatment failure often ensues due to tumor intrinsic or acquired radioresistance. Here we find that the MEK5/ERK5 signaling pathway is associated with resistance to genotoxic stress in aggressive prostate cancer cells. MEK5 knockdown by RNA interference sensitizes prostate cancer cells to ionizing radiation (IR) and etoposide treatment, as assessed by clonogenic survival and short-term proliferation assays. Mechanistically, MEK5 downregulation impairs phosphorylation of the catalytic subunit of DNA-PK at serine 2056 in response to IR or etoposide treatment. Although MEK5 knockdown does not influence the initial appearance of radiation- and etoposide-induced γH2AX and 53BP1 foci, it markedly delays their resolution, indicating a DNA repair defect. A cell-based assay shows that nonhomologous end joining (NHEJ) is compromised in cells with ablated MEK5 protein expression. Finally, MEK5 silencing combined with focal irradiation causes strong inhibition of tumor growth in mouse xenografts, compared with MEK5 depletion or radiation alone. These findings reveal a convergence between MEK5 signaling and DNA repair by NHEJ in conferring resistance to genotoxic stress in advanced prostate cancer and suggest targeting MEK5 as an effective therapeutic intervention in the management of this disease.

A MYC and RAS co-activation signature in localized prostate cancer drives bone metastasis and castration resistance.

Understanding the intricacies of lethal prostate cancer poses specific challenges due to difficulties in accurate modeling of metastasis in vivo. Here we show that NPK EYFP mice (for Nkx3.1 CreERT2/+ ; Pten flox/flox ; Kras LSL-G12D/+ ; R26R-CAG-LSL-EYFP/+) develop prostate cancer with a high penetrance of metastasis to bone, thereby enabling detection and tracking of bone metastasis in vivo and ex vivo. Transcriptomic and whole-exome analyses of bone metastasis from these mice revealed distinct molecular profiles conserved between human and mouse and specific patterns of subclonal branching from the primary tumor. Integrating bulk and single-cell transcriptomic data from mouse and human datasets with functional studies in vivo unravels a unique MYC/RAS co-activation signature associated with prostate cancer metastasis. Finally, we identify a gene signature with prognostic value for time to metastasis and predictive of treatment response in human patients undergoing androgen receptor therapy across clinical cohorts, thus uncovering conserved mechanisms of metastasis with potential translational significance.

RAD9A promotes metastatic phenotypes through transcriptional regulation of anterior gradient 2 (AGR2).

RAD9A plays an important role in prostate tumorigenesis and metastasis-related phenotypes. The protein classically functions as part of the RAD9A-HUS1-RAD1 complex but can also act independently. RAD9A can selectively transactivate multiple genes, including CDKN1A and NEIL1 by binding p53-consensus sequences in or near promoters. RAD9A is overexpressed in human prostate cancer specimens and cell lines; its expression correlates with tumor progression. Silencing RAD9A in prostate cancer cells impairs their ability to form tumors in vivo and migrate as well as grow anchorage independently in vitro. We demonstrate herein that RAD9A transcriptionally controls AGR2, a gene aberrantly overexpressed in patients with metastatic prostate cancer. Transient or stable knockdown of RAD9A in PC-3 cells caused downregulation of AGR2 protein abundance. Reduced AGR2 protein levels were due to lower abundance of AGR2 mRNA. The AGR2 genomic region upstream of the coding initiation site contains several p53 consensus sequences. RAD9A bound specifically to the 5'-untranslated region of AGR2 in PC-3 cells at a partial p53 consensus sequence at position +3136 downstream from the transcription start site, determined by chromatin immunoprecipitation, followed by PCR amplification. Binding of RAD9A to the p53 consensus sequence was sufficient to drive AGR2 gene transcription, shown by a luciferase reporter assay. In contrast, when the RAD9A-binding sequence on the AGR2 was mutated, no luciferase activity was detected. Knockdown of RAD9A in PC-3 cells impaired cell migration and anchorage-independent growth. However, ectopically expressed AGR2 in RAD9A-depleted PC-3 cells restored these phenotypes. Our results suggest RAD9A drives metastasis by controlling AGR2 abundance.

Cephalic venous aneurysm in the wrist.

Venous aneurysms are benign vascular lesions usually located in the neck, lower extremity, and abdomen, but rarely in the upper extremity. There may be a mistake or delay in diagnosis because they are uncommon. We report a case of a healthy 54-year-old man who had a cephalic venous aneurysm in his wrist that grew slowly over 20 years. The diagnosis was made on MRI and confirmed with excisional surgery. Radiologists should consider venous aneurysms in the differential when evaluating soft tissue masses as they will often be the first to make the correct diagnosis.

Cooperation of loss of NKX3.1 and inflammation in prostate cancer initiation.

Although it is known that inflammation plays a critical role in prostate tumorigenesis, the underlying processes are not well understood. Based on analysis of genetically engineered mouse models combined with correlative analysis of expression profiling data from human prostate tumors, we demonstrate a reciprocal relationship between inflammation and the status of the NKX3.1 homeobox gene associated with prostate cancer initiation. We find that cancer initiation in aged Nkx3.1 mutant mice correlates with enrichment of specific immune populations and increased expression of immunoregulatory genes. Furthermore, expression of these immunoregulatory genes is similarly increased in human prostate tumors having low levels of NKX3.1 expression. We further show that induction of prostatitis in Nkx3.1 mutant mice accelerates prostate cancer initiation, which is coincident with aberrant cellular plasticity and differentiation. Correspondingly, human prostate tumors having low levels of NKX3.1 have de-regulated expression of genes associated with these cellular processes. We propose that loss of function of NKX3.1 accelerates inflammation-driven prostate cancer initiation potentially via aberrant cellular plasticity and impairment of cellular differentiation.This article has an associated First Person interview with the first author of the paper.

The value of the UroVysion® FISH assay in the risk-stratification of patients with "atypical urothelial cells" in urinary cytology specimens.

BACKGROUND: The aim of this study was to evaluate the potential use of the UroVysion® fluorescent in situ hybridization test (U-FISH) to stratify the risk of urothelial carcinoma (UC) in patients with a diagnosis of "atypical urothelial cells" (AUC) in urinary tract cytology (UTCy). METHODS: Using a histologic diagnosis of UC and respectively of high grade UC (HGUC) within 12 months of the index UTCy as a reference standard, we determined the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of U-FISH for patients with AUC diagnosed 2008 to 2014. RESULTS: Of the 377 patients with AUC, 62 (16.45%) were diagnosed with UC (29 low grade UC and 33 HGUC) within 12 months. U-FISH were uninformative in 45 (11.94%), positive in 63 (16.71%) and negative in 269 (71.35%). UC was diagnosed more frequently in patients with positive than in those with negative U- FISH results (31/63, 49.21% vs. 25/269, 9.29%, P < 0.0001). The sensitivity, specificity, PPV, NPV and accuracy of U-FISH in the setting of AUC were 44.64%, 81.82%, 47.17%, 80.25%, and 71.91% for UC and respectively 48.39%, 78.77%. 28.3%, 89.81%, and 74.29% for HGUC. U-FISH showed a high false positive rate (28/53, 52.83%) that remained high even after extended follow-up, arguing against "anticipatory positive" results. CONCLUSIONS: U-FISH allows risk stratification in patients with AUC. However, its usefulness is diminished by the high false-positive rate, making it important to interpret U- FISH results in the patient's clinical context. Diagn. Cytopathol. 2017;45:481-500. © 2017 Wiley Periodicals, Inc.

Co-clinical Analysis of a Genetically Engineered Mouse Model and Human Prostate Cancer Reveals Significance of NKX3.1 Expression for Response to 5α-reductase Inhibition.

BACKGROUND: Although men on active surveillance for prostate cancer (PCa) may benefit from intervention with 5α-reductase inhibitors (5-ARIs), it has not been resolved whether 5-ARIs are effective for delaying disease progression and, if so, whether specific patients are more likely to benefit. OBJECTIVE: To identify molecular features predictive of patient response to 5-ARIs. DESIGN, SETTING, AND PARTICIPANTS: Nkx3.1 mutant mice, a model of early-stage PCa, were treated with the 5-ARI finasteride, and histopathological and molecular analyses were performed. Cross-species computational analyses were used to compare expression profiles for treated mice with those of patients who had received 5-ARIs before prostatectomy. INTERVENTION: Finasteride administered to Nkx3.1 mutant mice. 5-ARI-treated patient specimens obtained retrospectively. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Endpoints in mice included histopathology, immunohistochemistry, and molecular profiling. GraphPad Prism software, R-studio, and Matlab were used for statistical and data analyses. RESULTS AND LIMITATIONS: Finasteride treatment of Nkx3.1 mutant mice resulted in a significant reduction in prostatic intraepithelial neoplasia (PIN), as evident from histopathological and expression profiling analyses. Cross-species computational analysis comparing finasteride-treated mice with two independent 5-ARI-treated patient cohorts showed that reduced NKX3.1 expression is predictive of response to 5-ARI. A limitation of the study is that these retrospective human cohorts have relatively few patients with limited clinical outcome data. Future prospective clinical trials are needed to validate whether stratifying patients on the basis of NKX3.1 expression improves the benefit of 5-ARIs during active surveillance. CONCLUSIONS: This co-clinical study implicates NKX3.1 status as a predictor of response to 5-ARIs, and suggests that molecular features, including NKX3.1 expression, may help to identify PCa patients most likely to benefit from 5-ARIs during active surveillance. PATIENT SUMMARY: The aim of precision cancer prevention is to tailor interventions on the basis of individualized patient characteristics. We propose that patients with low NKX3.1 expression are optimal candidates for intervention with 5α-reductase inhibitors as an adjunct to active surveillance.

Variation of cytopathologists' use of the indeterminate diagnostic categories "atypical" and "suspicious for malignancy" in the cytologic diagnosis of solid pancreatic lesions on endoscopic ultrasound-guided fine-needle aspirates.

Indeterminate cytologic diagnoses in endoscopic ultrasound guided fine needle aspiration biopsy (EUS-FNA) of solid pancreatic lesions include the diagnostic categories "atypical" (ATY) and "suspicious for malignancy" (SUSP), which are used at variable rates and are associated with variable underlying risk of malignancy. The aim of this study was to determine individual cytopathologists' rates of indeterminate diagnoses in EUS-FNA of solid pancreatic lesions and their relationship to cytopathologists' experience and volume of pancreatic EUS-FNA examined, as well as the potential impact of departmental consensus review on indeterminate diagnoses. DESIGN: The diagnostic rates of ATY and SUSP and their underlying risk of malignancy were calculated for six cytopathologists who diagnosed 1,114 of 1,225 EUS-FNA of solid pancreatic lesions from 1/1/2001 to 9/15/2014, and were then compared for the periods before and after the implementation of departmental consensus review during 2009. RESULTS: The six cytopathologists diagnosed 10% of cases as indeterminate; 82 (7.4%) as "atypical" and 29 (2.6%) as "suspicious". The individual cytopathologists' indeterminate diagnosis rates varied twofold (6.67-12.80%) and did not correlate with their experience, total or annual volume of EUS-FNAs. Of the 56/99 (56.57%) cases with follow-up, the underlying rate of malignancy was 47% (35/75; for "atypical" and 87.5% (21/24); for "suspicious"). The underlying rates of malignancy were 33-67% for "atypical" and 80-100% for "suspicious" diagnoses made by individual cytopathologists. The rate of indeterminate diagnoses decreased from 11.55 to 7.88% after the implementation of departmental consensus review. CONCLUSION: Individual cytopathologists' rates of indeterminate diagnoses and their significance vary; however, consensus review is helpful in reducing these rates. Diagn. Cytopathol. 2017;45:3-13. © 2016 Wiley Periodicals, Inc.

NOTCH1 and SOX10 are Essential for Proliferation and Radiation Resistance of Cancer Stem-Like Cells in Adenoid Cystic Carcinoma.

PURPOSE: Although the existence of cancer stem cells (CSC) in adenoid cystic carcinoma (ACC) has been proposed, lack of assays for their propagation and uncertainty about molecular markers prevented their characterization. Our objective was to isolate CSC from ACC and provide insight into signaling pathways that support their propagation. EXPERIMENTAL DESIGN: To isolate CSC from ACC and characterize them, we used ROCK inhibitor-supplemented cell culture, immunomagnetic cell sorting, andin vitro/in vivoassays for CSC viability and tumorigenicity. RESULTS: We identified in ACC CD133-positive CSC that expressed NOTCH1 and SOX10, formed spheroids, and initiated tumors in nude mice. CD133(+)ACC cells produced activated NOTCH1 (N1ICD) and generated CD133(-)cells that expressed JAG1 as well as neural differentiation factors NR2F1, NR2F2, and p27Kip1. Knockdowns ofNOTCH1, SOX10, and their common effectorFABP7had negative effects on each other, inhibited spheroidogenesis, and induced cell death pointing at their essential roles in CSC maintenance. Downstream effects ofFABP7knockdown included suppression of a broad spectrum of genes involved in proliferation, ribosome biogenesis, and metabolism. Among proliferation-linked NOTCH1/FABP7 targets, we identified SKP2 and its substrate p27Kip1. A γ-secretase inhibitor, DAPT, selectively depleted CD133(+)cells, suppressed N1ICD and SKP2, induced p27Kip1, inhibited ACC growthin vivo, and sensitized CD133(+)cells to radiation. CONCLUSIONS: These results establish in the majority of ACC the presence of a previously uncharacterized population of CD133(+)cells with neural stem properties, which are driven by SOX10, NOTCH1, and FABP7. Sensitivity of these cells to Notch inhibition and their dependence on SKP2 offer new opportunities for targeted ACC therapies.

NTRK fusion oncogenes in pediatric papillary thyroid carcinoma in northeast United States.

BACKGROUND: An increase in thyroid cancers, predominantly papillary thyroid carcinoma (PTC), has been recently reported in children. METHODS: The histopathology of 28 consecutive PTCs from the northeast United States was reviewed. None of the patients (ages 6-18 years; 20 females, 8 males) had significant exposure to radiation. Nucleic acid from tumors was tested for genetic abnormalities (n = 27). Negative results were reevaluated by targeted next-generation sequencing. RESULTS: Seven of 27 PTCs (26%) had neurotrophic tyrosine kinase receptor (NTRK) fusion oncogenes (NTRK type 3/ets variant 6 [NTRK3/ETV6], n =5; NTRK3/unknown, n = 1; and NTRK type 1/translocated promoter region, nuclear basket protein [NTRK1/TPR], n = 1), including 5 tumors that measured >2 cm and 3 that diffusely involved the entire thyroid or lobe. All 7 tumors had lymphatic invasion, and 5 had vascular invasion. Six of 27 PTCs (22%) had ret proto-oncogene (RET) fusions (RET/PTC1, n = 5; RET/PTC3, n = 1); 2 tumors measured >2 cm and diffusely involved the thyroid, and 5 had lymphatic invasion, with vascular invasion in 2. Thirteen PTCs had the B-Raf proto-oncogene, serine/threonine kinase (BRAF) valine-to-glutamic acid mutation at position 600 (BRAF(V) (600E)) (13 of 27 tumors; 48%), 11 measured <2 cm, and 6 had lymphatic invasion (46%), with vascular invasion in 3. Fusion oncogene tumors, compared with BRAF(V) (600E) PTCs, were associated with large size (mean, 2.2 cm vs 1.5 cm, respectively; P = .05), solid and diffuse variants (11 of 13 vs 0 of 13 tumors, respectively; P < .001), and lymphovascular invasion (12 of 13 vs 6 of 13 tumors, respectively; P = .02); BRAF(V) (600E) PTCs were predominantly the classic variant (12 of 13 vs 1 of 13 tumors). Two tumors metastasized to the lung, and both had fusion oncogenes (NTRK1/TPR, n = 1; RET/PTC1, n = 1). CONCLUSIONS: Fusion oncogene PTC presents with more extensive disease and aggressive pathology than BRAF(V) (600E) PTC in the pediatric population. The high prevalence of the NTRK1/NTRK3 fusion oncogene PTCs in the United States is unusual and needs further investigation.

Interstitial Lung Diseases That Are Difficult to Classify: A Review of Bronchiolocentric Interstitial Lung Disease.

CONTEXT: Idiopathic bronchiolocentric interstitial pneumonia, airway-centered interstitial fibrosis, centrilobular fibrosis, and bronchiolitis interstitial pneumonia are increasingly recognized histopathologic variants of idiopathic interstitial pneumonia that are difficult to fit within existing classification schemes. OBJECTIVE: To review and analyze the appropriate literature that describes the spectrum of histopathologic changes in these conditions, in an effort to ascertain similarities as well as their differences. In addition, we examined associations with hypersensitivity, cigarette smoking, and survival data. DATA SOURCES: Relevant and peer-reviewed literature indexed in PubMed (National Library of Medicine) coupled with experience gained by review of personal cases with appropriate histopathology constitute the basis of this study. CONCLUSIONS: As anticipated, the common link among the above-cited conditions is their bronchiolocentricity, with a predominance of either fibrosis or inflammation. Clear-cut associations with hypersensitivity or cigarette smoking are not evident in this study. The airway-centered interstitial fibrosis variant of bronchiolocentric interstitial lung disease appears to have a poor outcome.

C-Cell Neoplasia in Asymptomatic Carriers of RET Mutation in Extracellular Cysteine-Rich and Intracellular Tyrosine Kinase Domain.

Germline mutations in RET proto-oncogene associated with multiple endocrine neoplasia type 2 (MEN2) may affect codons for the extracellular cysteine-rich (ECR) or the intracellular tyrosine kinase (ITK) domain of the transmembrane receptor tyrosine kinase protein. We compared C-cell pathology in asymptomatic carriers of RET mutation affecting the 2 domains. Twenty-two asymptomatic carriers (median age, 9.5 years), 10 with mutations in the ECR (codons 634, 611, 618, and 620) and 12 with mutations in the ITK domain (codons 804, 790, 891, and 918), underwent total thyroidectomy. C-cell hyperplasia was identified in 16 (73%), was multifocal and/or bilateral in 11, and was associated with medullary thyroid carcinoma (MTC) in 10 thyroids. When comparing the ECR and ITK groups in 21 carriers from MEN2A/familial MTC families, C-cell hyperplasia was more frequent in the former (90% versus 55%), as was multifocality (70% versus 27%) and MTC (60% versus 27%), despite the significantly younger median age in the former group (5 versus 23 years, P = .04). One asymptomatic carrier had de novo codon 918 mutation (MEN2B) and showed bilateral microcarcinoma with lymph node metastasis at presentation and progressive disease on follow-up. In conclusion, asymptomatic carriers of high-risk RET mutations affecting the ECR were significantly younger and frequently showed C-cell neoplasia, multifocality, and MTC when compared with mutations affecting the ITK domain in the MEN2A/familial MTC families. The presence of C-cell disease, its severity, and aggressiveness correlated with the mutated codon and with increasing age.