Fibronectin Contributes to a BRAF Inhibitor-driven Invasive Phenotype in Thyroid Cancer through EGR1, Which Can Be Blocked by Inhibition of ERK1/2.

Mutations in BRAF are common in advanced papillary and anaplastic thyroid cancer (PTC and ATC). However, patients with BRAF-mutant PTC currently lack therapies targeting this pathway. Despite the approved combination of BRAF and MEK1/2 inhibition for patients with BRAF-mutant ATC, these patients often progress. Thus, we screened a panel of BRAF-mutant thyroid cancer cell lines to identify new therapeutic strategies. We showed that thyroid cancer cells resistant to BRAF inhibition (BRAFi) exhibit an increase in invasion and a proinvasive secretome in response to BRAFi. Using reverse-phase protein array (RPPA), we identified a nearly 2-fold increase in expression of the extracellular matrix protein, fibronectin, in response to BRAFi treatment, and a corresponding 1.8- to 3.0-fold increase in fibronectin secretion. Accordingly, the addition of exogenous fibronectin phenocopied the BRAFi-induced increase in invasion while depletion of fibronectin in resistant cells resulted in loss of increased invasion. We further showed that BRAFi-induced invasion can be blocked by inhibition of ERK1/2. In a BRAFi-resistant patient-derived xenograft model, we found that dual inhibition of BRAF and ERK1/2 slowed tumor growth and decreased circulating fibronectin. Using RNA sequencing, we identified EGR1 as a top downregulated gene in response to combined BRAF/ERK1/2 inhibition, and we further showed that EGR1 is necessary for a BRAFi-induced increase in invasion and for induction of fibronectin in response to BRAFi. IMPLICATIONS: Together, these data show that increased invasion represents a new mechanism of resistance to BRAF inhibition in thyroid cancer that can be targeted with an ERK1/2 inhibitor.

Mutual exclusivity of ESR1 and TP53 mutations in endocrine resistant metastatic breast cancer.

Both TP53 and ESR1 mutations occur frequently in estrogen receptor positive (ER+) metastatic breast cancers (MBC) and their distinct roles in breast cancer tumorigenesis and progression are well appreciated. Recent clinical studies discovered mutual exclusivity between TP53 and ESR1 mutations in metastatic breast cancers; however, mechanisms underlying this intriguing clinical observation remain largely understudied and unknown. Here, we explored the interplay between TP53 and ESR1 mutations using publicly available clinical and experimental data sets. We first confirmed the robust mutational exclusivity using six independent cohorts with 1,056 ER+ MBC samples and found that the exclusivity broadly applies to all ER+ breast tumors regardless of their clinical and distinct mutational features. ESR1 mutant tumors do not exhibit differential p53 pathway activity, whereas we identified attenuated ER activity and expression in TP53 mutant tumors, driven by a p53-associated E2 response gene signature. Further, 81% of these p53-associated E2 response genes are either direct targets of wild-type (WT) p53-regulated transactivation or are mutant p53-associated microRNAs, representing bimodal mechanisms of ER suppression. Lastly, we analyzed the very rare cases with co-occurrences of TP53 and ESR1 mutations and found that their simultaneous presence was also associated with reduced ER activity. In addition, tumors with dual mutations showed higher levels of total and PD-L1 positive macrophages. In summary, our study utilized multiple publicly available sources to explore the mechanism underlying the mutual exclusivity between ESR1 and TP53 mutations, providing further insights and testable hypotheses of the molecular interplay between these two pivotal genes in ER+ MBC.

Lenvatinib Plus Anti-PD-1 Combination Therapy for Advanced Cancers: Defining Mechanisms of Resistance in an Inducible Transgenic Model of Thyroid Cancer.

Background: Combination therapy with lenvatinib plus programmed death-1 (PD-1) immune checkpoint blockades (ICBs) is under investigation in many solid tumors, including thyroid cancer. Lenvatinib is known to reduce angiogenesis and may overturn the immunosuppressive effects of vascular endothelial growth factor in the tumor microenvironment. Previous studies investigating the effects of VEGF receptor inhibition on the immune response were performed in rapidly growing tumor models where immune equilibrium is not established before treatment. We hypothesize that physiologically relevant preclinical models are necessary to define mechanisms of resistance to immune-targeted combination therapies. Methods: We utilized the TPO-CreER/BrafV600E/wt/Trp53Δex2-10/Δex2-10 inducible transgenic model of advanced thyroid cancer to investigate lenvatinib treatment in the context of an anti-PD-1 ICB. Following tumor establishment, 3.5 months postinduction, mice were treated with high- (10 mg/kg) or low-dose (2 mg/kg) lenvatinib, anti-PD-1, or combination of lenvatinib with anti-PD-1. Tumor volume and lung metastases were assessed in each group. Immune infiltrate was characterized by flow cytometry and immunohistochemistry, and TCRß sequencing was performed to further investigate the T cell response. Results: Both low- and high-dose lenvatinib reduced tumor volume, while anti-PD-1 had no effect, alone or in combination. Although both low- and high-dose lenvatinib reduced vascular density, low-dose lenvatinib was superior in controlling tumor size. Lung metastases and survival were not improved with therapy despite the effects of lenvatinib on primary tumor size. Low-dose lenvatinib treatment led to a subtle reduction in the dominant Ly6G+CD11b+ myeloid cell population and was associated with increased CD4+ T cell infiltrate and enrichment in 4-1BB+ and granzyme B+ CD4+ T cells and FoxP3+ regulatory T cells. Polyclonal T cell expansion was evident in the majority of mice, suggesting that a tumor-specific T cell response was generated. Conclusions: The effects of lenvatinib on the immune response were most pronounced in mice treated with low-dose lenvatinib, suggesting that dose should be considered in clinical application. While the immune-modulating potential of lenvatinib is encouraging, alterations in the immune milieu and T cell activation status were insufficient to sustain durable tumor regression, even with added anti-PD-1. Additional studies are necessary to develop more effective combination approaches in low-mutation burden tumors, such as thyroid cancer.

Inhibition of BRAF and ERK1/2 has synergistic effects on thyroid cancer growth in vitro and in vivo.

Mutations in the BRAF gene are highly prevalent in thyroid cancer. However, the response rate of thyroid tumors to BRAF-directed therapies has been mixed. Increasingly, combination therapies inhibiting the MAPK pathway at multiple nodes have shown promise. Recently developed ERK1/2 inhibitors are of interest for use in combination therapies as they have the advantage of inhibiting the most downstream node of the MAPK pathway, therefore preventing pathway reactivation. Here, we examined the effect of combined BRAF inhibition (dabrafenib) and ERK1/2 inhibition (SCH772984) on the growth and survival of a panel of BRAF-mutant thyroid cancer cell lines using in vitro and in vivo approaches. We found that resistance due to MAPK pathway reactivation occurs quickly with single-agent BRAF inhibition, but can be prevented with combined BRAF and ERK1/2 inhibition. Combined inhibition also results in synergistic growth inhibition, decreased clonogenic survival, and enhanced induction of apoptosis in a subset of BRAF-mutant thyroid cancer cells. Finally, combined inhibition of BRAF and ERK1/2 results in enhanced inhibition of tumor growth in an anaplastic thyroid cancer in vivo model. These results provide key rationale to pursue combined BRAF and ERK1/2 inhibition as an alternative therapeutic strategy for BRAF-mutant advanced thyroid cancer patients.

Paraneoplastic Encephalitis Associated with Locally Advanced Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer.

Paraneoplastic neurologic diseases (PND) are rare but can occur in patients with common malignancies including breast cancer. In patients with hormone receptor (HR)-negative human epidermal growth factor receptor 2 (HER2)-positive breast cancer, PND have been reported in association with anti-Yo antibodies and with clinical presentation of paraneoplastic cerebellar degeneration. We describe the case of a woman with progressively altered mental status and seizures, ultimately requiring admission. Based on her clinical presentation, imaging findings, and evidence of neural-directed antibodies in her serum and cerebrospinal fluid, she was diagnosed with paraneoplastic limbic encephalitis (LE) due to an underlying HR-negative, HER2-positive breast cancer. She showed a transient response to immunosuppression but had more significant improvement after surgical resection and initiation of chemotherapy along with HER2-directed therapy. To the best of our knowledge, this is the first documented case of paraneoplastic LE in a patient with HR-negative, HER2-positive breast cancer likely caused by the production of an unclassified anti-neuronal antibody.

Steroid Hormone Receptor and Infiltrating Immune Cell Status Reveals Therapeutic Vulnerabilities of ESR1-Mutant Breast Cancer.

Mutations in ESR1 that confer constitutive estrogen receptor alpha (ER) activity in the absence of ligand are acquired by ≥40% of metastatic breast cancers (MBC) resistant to adjuvant aromatase inhibitor (AI) therapy. To identify targetable vulnerabilities in MBC, we examined steroid hormone receptors and tumor-infiltrating immune cells in metastatic lesions with or without ER mutations. ER and progesterone receptor (PR) were significantly lower in metastases with wild-type (WT) ER compared with those with mutant ER, suggesting that metastases that evade AI therapy by mechanism(s) other than acquiring ER mutations lose dependency on ER and PR. Metastases with mutant ER had significantly higher T regulatory and Th cells, total macrophages, and programmed death ligand-1 (PD-L1)-positive immune-suppressive macrophages than those with WT ER. Breast cancer cells with CRISPR-Cas9-edited ER (D538G, Y537S, or WT) and patient-derived xenografts harboring mutant or WT ER revealed genes and proteins elevated in mutant ER cells, including androgen receptor (AR), chitinase-3-like protein 1 (CHI3L1), and IFN-stimulated genes (ISG). Targeting these proteins blunted the selective advantage of ER-mutant tumor cells to survive estrogen deprivation, anchorage independence, and invasion. Thus, patients with mutant ER MBC might respond to standard-of-care fulvestrant or other selective ER degraders when combined with AR or CHI3L1 inhibition, perhaps with the addition of immunotherapy. SIGNIFICANCE: Targetable alterations in MBC, including AR, CHI3L1, and ISG, arise following estrogen-deprivation, and ER-mutant metastases may respond to immunotherapies due to elevated PD-L1+ macrophages.See related article by Arnesen et al., p. 539.

Establishment and Characterization of Four Novel Thyroid Cancer Cell Lines and PDX Models Expressing the RET/PTC1 Rearrangement, BRAFV600E, or RASQ61R as Drivers.

Cancer cell lines are critical models to study tumor progression and response to therapy. In 2008, we showed that approximately 50% of thyroid cancer cell lines were redundant or not of thyroid cancer origin. We therefore generated new authenticated thyroid cancer cell lines and patient-derived xenograft (PDX) models using in vitro and feeder cell approaches, and characterized these models in vitro and in vivo. We developed four thyroid cancer cell lines, two derived from 2 different patients with papillary thyroid cancer (PTC) pleural effusions, CUTC5, and CUTC48; one derived from a patient with anaplastic thyroid cancer (ATC), CUTC60; and one derived from a patient with follicular thyroid cancer (FTC), CUTC61. One PDX model (CUTC60-PDX) was also developed. Short tandem repeat (STR) genotyping showed that each cell line and PDX is unique and match the original patient tissue. The CUTC5 and CUTC60 cells harbor the BRAF (V600E) mutation, the CUTC48 cell line expresses the RET/PTC1 rearrangement, and the CUTC61 cells have the HRAS (Q61R) mutation. Moderate to high levels of PAX8 and variable levels of NKX2-1 were detected in each cell line and PDX. The CUTC5 and CUTC60 cell lines form tumors in orthotopic and flank xenograft mouse models. IMPLICATIONS: We have developed the second RET/PTC1-expressing PTC-derived cell line in existence, which is a major advance in studying RET signaling. We have further linked all cell lines to the originating patients, providing a set of novel, authenticated thyroid cancer cell lines and PDX models to study advanced thyroid cancer.

Oncocytic variant of medullary thyroid carcinoma; a rare tumor with numerous diagnostic mimics by fine needle aspiration.

Oncocytic variant of medullary thyroid carcinoma is rare form of thyroid carcinoma that is easily misdiagnosed on fine needle aspiration specimens due to it is low incidence and cytomorphologic overlap with other more common Hurtle cell lesions. A correct initial diagnosis by fine needle aspiration is imperative as the clinical treatment for medullary carcinoma differs significantly from the mimickers. We present a case of this rare variant tumor that on initial fine needle aspiration was described as a Hurthle cell lesion and was subsequently correctly classified on the resection specimen. In this brief review, we describe the cytomorphologic features of medullary carcinoma, oncocytic variant of medullary carcinoma and it is most common mimickers, and we discuss the ancillary studies required to confirm the diagnosis. This case highlights the importance of a complete clinical history and radiologic correlation, which in conjunction with a careful attention to the cytologic features of the fine needle aspiration sample, should in most cases ensure a correct initial diagnosis.

Discordance Between Intraoperative Consultation by Frozen Section and Final Diagnosis.

Discrepancies between intraoperative consultations with frozen section diagnosis and the final pathology report have the potential to alter treatment decisions and affect patient care. Monitoring these correlations is a key component of laboratory quality assurance, however identifying specific areas for improvement can be difficult to attain. Our goal is to develop a standardized method utilizing root cause analysis and a modified Eindhoven classification schematic to identify the source of discrepancies and deferrals and subsequently to guide performance improvement initiatives. A retrospective review of intraoperative consultations performed at a tertiary level hospital and cancer center over a 6-month period identified deferrals and discrepancies between the intraoperative consult report and the final pathology report. We developed and applied a classification tool to identify the process errors and cognitive errors leading to discrepant results. A total of 48 (4.6%) discrepancies and 24 (2.3%) deferrals were identified from the 1042 frozen sections. Within the entire data set of frozen sections, the process errors (n = 26, 54.2%) were due to gross sampling (n = 16, 33.3%), histologic sampling (n = 8, 16.7%), and surgical sampling (n = 2, 4.2%). Interpretation errors (n = 22, 45.8%) included undercalls/false negatives (n=8, 16.7%), overcalls/false positives (n = 10, 20.8%), and misclassification errors (n = 4, 8.3%). Application of our classification tool demonstrated that the root cause of discrepancies and deferrals varied both between organ systems and by specific organs and that classification models may be utilized as a standardized method to identify focused areas for improvement.

Fibroblast Subtypes Regulate Responsiveness of Luminal Breast Cancer to Estrogen.

Purpose: Antiendocrine therapy remains the most effective treatment for estrogen receptor-positive (ER+) breast cancer, but development of resistance is a major clinical complication. Effective targeting of mechanisms that control the loss of ER dependency in breast cancer remains elusive. We analyzed breast cancer-associated fibroblasts (CAF), the largest component of the tumor microenvironment, as a factor contributing to ER expression levels and antiendocrine resistance.Experimental Design: Tissues from patients with ER+ breast cancer were analyzed for the presence of CD146-positive (CD146pos) and CD146-negative (CD146neg) fibroblasts. ER-dependent proliferation and tamoxifen sensitivity were evaluated in ER+ tumor cells cocultured with CD146pos or CD146neg fibroblasts. RNA sequencing was used to develop a high-confidence gene signature that predicts for disease recurrence in tamoxifen-treated patients with ER+ breast cancer.Results: We demonstrate that ER+ breast cancers contain two CAF subtypes defined by CD146 expression. CD146neg CAFs suppress ER expression in ER+ breast cancer cells, decrease tumor cell sensitivity to estrogen, and increase tumor cell resistance to tamoxifen therapy. Conversely, the presence of CD146pos CAFs maintains ER expression in ER+ breast cancer cells and sustains estrogen-dependent proliferation and sensitivity to tamoxifen. Conditioned media from CD146pos CAFs with tamoxifen-resistant breast cancer cells are sufficient to restore tamoxifen sensitivity. Gene expression profiles of patient breast tumors with predominantly CD146neg CAFs correlate with inferior clinical response to tamoxifen and worse patient outcomes.Conclusions: Our data suggest that CAF composition contributes to treatment response and patient outcomes in ER+ breast cancer and should be considered a target for drug development. Clin Cancer Res; 23(7); 1710-21. ©2016 AACR.

Metastatic Urothelial Carcinoma to the Uterine Cervix: A Case Report of a Rare Entity and Review of the Diagnostic Differential.

Urothelial carcinoma (UC) rarely metastasizes to the gynecologic tract, occurring in descending order of frequency, within the vagina, uterus, ovaries, and cervix. Significant morphologic overlap exists between primary gynecologic squamous lesions (both benign and malignant) and metastatic UC, thus potentially hindering a timely and accurate diagnosis. We present a case of UC metastatic to the uterine cervix in a 69-year-old female initially found to have noninvasive high-grade papillary UC of the bladder. Complaints of vaginal spotting lead to identification and biopsy of a mass in the uterine cervix. Histologic evaluation of the cervical mass showed a neoplastic proliferation of atypical epithelioid cells arranged in a papillary architecture. The differential in this case included primary uterine cervical tumors such as condyloma acuminatum, immature condyloma, verrucous carcinoma, warty/condylomatous carcinoma, and papillary squamotransitional cell carcinoma, as well as metastatic UC. A careful evaluation of histologic variances and a selective immunohistochemical panel allows differentiation of these tumors. We herein review the subtle, albeit significant, histologic and immunohistochemical differences of the aforementioned lesions.

FAK Expression, Not Kinase Activity, Is a Key Mediator of Thyroid Tumorigenesis and Protumorigenic Processes.

UNLABELLED: There are limited therapy options for advanced thyroid cancer, including papillary and anaplastic thyroid cancer (PTC and ATC). Focal adhesion kinase (FAK) regulates cell signaling by functioning as a scaffold and kinase. Previously, we demonstrated that FAK is overexpressed and activated in thyroid cancer cells and human PTC clinical specimens. However, it remains unclear whether patients with advanced thyroid cancer will benefit from FAK inhibition. Therefore, the dual functions of FAK in mediating protumorigenic processes and thyroid tumorigenesis were investigated. Evidence here shows that FAK expression predominantly regulates thyroid cancer cell growth, viability, and anchorage-independent growth. FAK inhibition, with PF-562,271 treatment, modestly reduced tumor volumes, while FAK depletion, through shRNA knockdown, significantly reduced tumor volumes in vivo A role for FAK expression in tumor establishment was demonstrated in a model of PTC, where FAK knockdown tumors did not develop. FAK depletion also led to a significant decrease in overall metastatic burden. Interestingly, pretreatment with a FAK inhibitor resulted in a paradoxical increase in metastasis in a model of ATC, but decreased metastasis in a model of PTC. These data provide the first evidence that FAK expression is critical for the regulation of thyroid tumorigenic functions. IMPLICATIONS: This study demonstrates that FAK expression, but not kinase activity alone, predominantly mediates thyroid tumor growth and metastasis, indicating that targeting the scaffolding function(s) of FAK may be an important therapeutic strategy for advanced thyroid cancer, as well as other FAK-dependent tumors. Mol Cancer Res; 14(9); 869-82. ©2016 AACR.

Tumor-Infiltrating T Cells and the PD-1 Checkpoint Pathway in Advanced Differentiated and Anaplastic Thyroid Cancer.

CONTEXT: Five to 10% of patients with differentiated thyroid cancers (DTC) develop invasive and/or distant metastatic disease that is marginally improved with standard therapies. Prognosis is poor for patients with anaplastic thyroid cancer, with a median survival of 3-5 months. We suggest that a paradigm shift is necessary in the treatment of advanced cases. OBJECTIVE: We hypothesized that a T-cell response is generated in advanced thyroid cancer and may be a viable therapeutic target. DESIGN: Primary DTCs were analyzed by quantitative RT-PCR (n = 92) for expression of CD3, CD8, forkhead box (Fox)-P3, programmed death (PD)-1, PD-1 ligand-1, and PD-1 ligand-2 and biopsied for cellular analysis by flow cytometry (n = 11). Advanced pT4 cases (n = 22) and metastases (n = 5) were analyzed by immunohistochemistry. SETTING: The study was conducted at the University of Colorado Hospital. PATIENTS: Thyroid cancer patients undergoing thyroidectomy or completion surgery for advanced disease between 2002 and 2013 participated in the study. INTERVENTION: There were no interventions. MAIN OUTCOME MEASURE: Immune markers were analyzed for association with disease severity. RESULTS: Immune markers were commonly expressed at the RNA level. PD-L1 was higher (P = .0443) in patients with nodal metastases. FoxP3(+) (P < .0001), PD-1(+)CD8(+) (P = .0058), and PD-1(+)CD4(+) (P = .0104) T cells were enriched in DTC biopsies. CD8(+) and FoxP3(+) T cells were detected by immunohistochemistry in all pT4 tumors and a subset of metastases. PD-1(+) lymphocytes were found in 50% of DTCs. PD-L1 was expressed by tumor and associated leukocytes in 13 of 22 cases, and expression was more diffuse in anaplastic thyroid cancer (P = .0373). BRAF(V600E) mutation was associated with higher frequencies of tumor-associated lymphocytes (P = .0095) but not PD-L1 expression. CONCLUSIONS: PD-1 checkpoint blockades may have therapeutic efficacy in patients with aggressive forms of thyroid cancer.

The clinical impact of immediate on-site cytopathology evaluation during endoscopic ultrasound-guided fine needle aspiration of pancreatic masses: a prospective multicenter randomized controlled trial.

OBJECTIVES: Observational data on the impact of on-site cytopathology evaluation (OCE) during endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) of pancreatic masses have reported conflicting results. We aimed to compare the diagnostic yield of malignancy and proportion of inadequate specimens between patients undergoing EUS-FNA of pancreatic masses with and without OCE. METHODS: In this multicenter randomized controlled trial, consecutive patients with solid pancreatic mass underwent randomization for EUS-FNA with or without OCE. The number of FNA passes in the OCE+ arm was dictated by the on-site cytopathologist, whereas seven passes were performed in OCE- arm. EUS-FNA protocol was standardized, and slides were reviewed by cytopathologists using standardized criteria for cytologic characteristics and diagnosis. RESULTS: A total of 241 patients (121 OCE+, 120 OCE-) were included. There was no difference between the two groups in diagnostic yield of malignancy (OCE+ 75.2% vs. OCE- 71.6%, P=0.45) and proportion of inadequate specimens (9.8 vs. 13.3%, P=0.31). Procedures in OCE+ group required fewer EUS-FNA passes (median, OCE+ 4 vs. OCE- 7, P<0.0001). There was no significant difference between the two groups with regard to overall procedure time, adverse events, number of repeat procedures, costs (based on baseline cost-minimization analysis), and accuracy (using predefined criteria for final diagnosis of malignancy). There was no difference between the two groups with respect to cytologic characteristics of cellularity, bloodiness, number of cells/slide, and contamination. CONCLUSIONS: Results of this study demonstrated no significant difference in the diagnostic yield of malignancy, proportion of inadequate specimens, and accuracy in patients with pancreatic mass undergoing EUS-FNA with or without OCE.

Characterization of thyroid cancer cell lines in murine orthotopic and intracardiac metastasis models.

Thyroid cancer incidence has been increasing over time, and it is estimated that ∼1950 advanced thyroid cancer patients will die of their disease in 2015. To combat this disease, an enhanced understanding of thyroid cancer development and progression as well as the development of efficacious, targeted therapies are needed. In vitro and in vivo studies utilizing thyroid cancer cell lines and animal models are critically important to these research efforts. In this report, we detail our studies with a panel of authenticated human anaplastic and papillary thyroid cancer (ATC and PTC) cell lines engineered to express firefly luciferase in two in vivo murine cancer models-an orthotopic thyroid cancer model as well as an intracardiac injection metastasis model. In these models, primary tumor growth in the orthotopic model and the establishment and growth of metastases in the intracardiac injection model are followed in vivo using an IVIS imaging system. In the orthotopic model, the ATC cell lines 8505C and T238 and the PTC cell lines K1/GLAG-66 and BCPAP had take rates >90 % with final tumor volumes ranging 84-214 mm(3) over 4-5 weeks. In the intracardiac model, metastasis establishment was successful in the ATC cell lines HTh74, HTh7, 8505C, THJ-16T, and Cal62 with take rates ≥70 %. Only one of the PTC cell lines tested (BCPAP) was successful in the intracardiac model with a take rate of 30 %. These data will be beneficial to inform the choice of cell line and model system for the design of future thyroid cancer studies.

PD-1+Tim-3+ CD8+ T Lymphocytes Display Varied Degrees of Functional Exhaustion in Patients with Regionally Metastatic Differentiated Thyroid Cancer.

Regional metastatic differentiated thyroid cancer (mDTC) provides a unique model in which to study the tumor-immune interface. These lymph node metastases persist for years, generally without progression to distant metastases. Although the immune system likely impedes disease progression, it is unsuccessful in eliminating disease. Our previous studies revealed that programmed death-1 (PD-1)(+) T cells were enriched in tumor-involved lymph nodes (TILN). Tumor-associated leukocytes and tumor cells were collected from grossly involved lymph nodes from 12 patients to further characterize the phenotype and functional potential of mDTC-associated PD-1(+) T cells. PD-1(+)CD4(+) and PD-1(+)CD8(+) T cells were enriched in 8 of 12 TILN samples. PD-1(+) T cells coexpressed Tim-3 and CD69 and failed to downregulate CD27. CD8(+) T cells, but not CD4(+) T cells, from these samples were variably deficient in their ability to produce effector cytokines when compared with control TILNs that lacked resident PD-1(+) T cells. PD-1(+)CD8(+) T cells were capable of exocytosis but lacked intracellular perforin. Surprisingly, T-cell proliferative capacity was largely maintained in all samples. Thus, although PD-1 expression by mDTC-associated CD8(+) T cells was associated with dysfunction, exhaustion was not complete. Notably, molecular markers of exhaustion did not translate to dysfunction in all samples or in CD4(+) T cells. Regulatory T cells (Treg), PD-L1, and galectin-9 were commonly found in mDTC and likely contributed to the initiation of T-cell exhaustion and disease progression. Therapies that release the effects of PD-1 and Tim-3 and reduce the suppressive effects of Tregs may encourage tumor elimination in patients with mDTC.

Massive dissemination from spinal cord gangliogliomas negative for BRAF V600E: report of two rare adult cases.

OBJECTIVES: Metastatic leptomeningeal spread from spinal cord gangliogliomas (GGs) is exceedingly rare. METHODS: Two adult women, aged 27 and 51 years, died of massive disseminations of cervicothoracic GGs 4 and 6 years, respectively, after initial diagnoses; full autopsies were performed. BRAF status was assessed by VE1 immunohistochemistry (IHC), Sanger sequencing, and a single-nucleotide base extension assay (SNaPshot, Applied Biosystems, Princeton, NJ). RESULTS: The 27-year-old underwent two biopsies, chemotherapy, radiation, and ventriculoperitoneal shunt placement; she developed craniospinal and peritoneal dissemination. Autopsy confirmed shunt-mediated peritoneal metastases, microscopic bone marrow involvement, and profuse spinal and supratentorial leptomeningeal and parenchymal spread. The 51-year-old underwent two resections, radiation, and chemotherapy and developed pancytopenia with biopsy-proven bony metastases 15 months before death. Autopsy demonstrated leptomeningeal, subpial, and subependymal metastases. The tumors in both primary and metastatic sites were BRAF negative by VE1 IHC and two different mutational analyses. This compared with negative BRAF results for an additional four nonmetastatic adult nonsupratentorial GGs and in our study. CONCLUSIONS: We document two rare cases of massively metastatic spinal cord GGs in adult patients who were negative for BRAF V600E mutations via multiple methods.

Thioredoxin interacting protein (TXNIP) is a novel tumor suppressor in thyroid cancer.

BACKGROUND: Thyroid cancer is the most common endocrine malignancy, and many patients with metastatic differentiated thyroid cancer (DTC), poorly differentiated thyroid cancer (PDTC), and anaplastic thyroid cancer (ATC) fail to respond to conventional therapies, resulting in morbidity and mortality. Additional therapeutic targets and treatment options are needed for these patients. We recently reported that peroxisome proliferator-activated receptor gamma (PPARγ) is highly expressed in ATC and confers an aggressive phenotype when overexpressed in DTC cells. METHODS: Microarray analysis was used to identify downstream targets of PPARγ in ATC cells. Western blot analysis and immunohistochemistry (IHC) were used to assess thioredoxin interacting protein (TXNIP) expression in thyroid cancer cell lines and primary tumor specimens. Retroviral transduction was used to generate ATC cell lines that overexpress TXNIP, and assays that assess glucose uptake, viable cell proliferation, and invasion were used to characterize the in vitro properties of these cells. An orthotopic thyroid cancer mouse model was used to assess the effect of TXNIP overexpression in ATC cell lines in vivo. RESULTS: Using microarray analysis, we show that TXNIP is highly upregulated when PPARγ is depleted from ATC cells. Using Western blot analysis and IHC, we show that DTC and ATC cells exhibit differential TXNIP expression patterns. DTC cell lines and patient tumors have high TXNIP expression in contrast to low or absent expression in ATC cell lines and tumors. Overexpression of TXNIP decreases the growth of HTh74 cells compared to vector controls and inhibits glucose uptake in the ATC cell lines HTh74 and T238. Importantly, TXNIP overexpression in T238 cells results in attenuated tumor growth and decreased metastasis in an orthotopic thyroid cancer mouse model. CONCLUSIONS: Our findings indicate that TXNIP functions as a tumor suppressor in thyroid cells, and its downregulation is likely important in the transition from differentiated to advanced thyroid cancer. These studies underscore the potential of TXNIP as a novel therapeutic target and prognostic indicator in advanced thyroid cancer.

Targeted inhibition of Src kinase with dasatinib blocks thyroid cancer growth and metastasis.

PURPOSE: There are no effective therapies for patients with poorly differentiated papillary thyroid cancer (PTC) or anaplastic thyroid cancer (ATC), and metastasis to the bone represents a significantly worse prognosis. Src family kinases (SFKs) are overexpressed and activated in numerous tumor types and have emerged as a promising therapeutic target, especially in relation to metastasis. We recently showed that Src is overexpressed and activated in thyroid cancer. We therefore tested whether inhibition of Src with dasatinib (BMS-354825) blocks thyroid cancer growth and metastasis. EXPERIMENTAL DESIGN: The effects of dasatinib on thyroid cancer growth, signaling, cell cycle, and apoptosis were evaluated in vitro. The therapeutic efficacy of dasatinib was further tested in vivo using an orthotopic and a novel experimental metastasis model. Expression and activation of SFKs in thyroid cancer cells was characterized, and selectivity of dasatinib was determined using an Src gatekeeper mutant. RESULTS: Dasatinib treatment inhibited Src signaling, decreased growth, and induced cell-cycle arrest and apoptosis in a subset of thyroid cancer cells. Immunoblotting showed that c-Src and Lyn are expressed in thyroid cancer cells and that c-Src is the predominant SFK activated. Treatment with dasatinib blocked PTC tumor growth in an orthotopic model by more than 90% (P = 0.0014). Adjuvant and posttreatment approaches with dasatinib significantly inhibited metastasis (P = 0.016 and P = 0.004, respectively). CONCLUSION: These data provide the first evidence that Src is a central mediator of thyroid cancer growth and metastasis, indicating that Src inhibitors may have a higher therapeutic efficacy in thyroid cancer, as both antitumor and antimetastatic agents.

The role of cytology specimens in molecular testing of solid tumors: techniques, limitations, and opportunities.

Numerous studies have demonstrated the suitability of cytology specimens for molecular analysis. When combined with the ability to acquire tissue in a minimally invasive manner, testing on cytology specimens is an especially attractive method for further refining diagnosis, determining prognosis, and predicting likely response to therapy as well as monitoring disease. As the demand for testing of small specimens increases, the burden of determining whether a specimen should be referred for testing will increasingly be placed on the pathologist. Although molecular laboratories that perform this testing will also evaluate the suitability of the specimen, familiarity with the criteria for suitability, which includes an understanding of the limitations of the assay methodology, will assist in determining which specimens are appropriate for referral. Selection of specimen(s) for testing should be paired with knowledge of the testing methodology used and its limitations, as well as the tumor enrichment capabilities of the laboratory. In addition to an expanding need to participate in the referral of specimens for testing, the cytopathologist will increasingly serve as a critical link in the communication between molecular laboratory and clinical team.