American Thyroid Association Guidelines and Statements: Past, Present, and Future

BACKGROUND

The American Thyroid Association (ATA) is continually striving to improve the quality of its publications. The ATA Guidelines Policies and Procedures Task Force was active during 2017. It recently recommended convening a formal standing committee to review and update policies and procedures for the development of clinical practice guidelines (CPGs) and Statements on an ongoing basis.

OBJECTIVE

This statement reviews the history of official ATA publications and discusses the challenges and findings identified by the Task Force. We also wish to present our "work in progress" and propose future directions for the new ATA Guidelines and Statements Committee (ATA GSC).

METHODS

Our Task Force reviewed the publication record of the ATA with respect to CPGs. We also reviewed existing ATA policies for CPGs and other official statements, examined policies of other organizations, solicited input from external experts and organizations, and convened five conference calls and two in-person meetings.

RESULTS

The ATA has a rich history of developing official publications that have been influential based on download and citation records as well as changes in practice trends. Key future issues to be further addressed by the ATA GSC include the following: (i) striving to improve the methodologic rigor of development of CPGs while balancing considerations of feasibility and timeliness and the role of transparently communicated expert opinion; (ii) formalizing a framework and process for development of new Statements; (iii) increasing stringency and transparency of management of competing interests of individuals being considered for CPG/Statement panel membership; (iv) encouraging consideration of equity and diversity in CPG/Statement development group composition; (v) increasing relevant stakeholder representation (including patient representatives) in development of CPGs/Statements; and (vi) expanding future guideline implementation strategies.

CONCLUSIONS

As shown by the completed literature search, the ATA has a long history of producing CPGs and Statements with global impact on informing clinical management, education, and research in thyroid diseases. The ATA remains committed to a process of continual improvement of its publications and to meeting stakeholder information needs. Based on the work of our Task Force, we have identified many elements that are needed to achieve this goal and areas of challenge for our new committee.

Pioglitazone Therapy of PAX8-PPARγ Fusion Protein Thyroid Carcinoma

CONTEXT

A subset of thyroid carcinomas expresses an oncogenic paired box 8 (PAX8) and peroxisome proliferator activated receptor γ (PPARγ) fusion protein (PPFP). The PPARγ/PPFP ligand pioglitazone is highly therapeutic in a transgenic mouse model of PPFP thyroid carcinoma, but whether pioglitazone is therapeutic in patients with PPFP thyroid carcinoma is unknown.

CASE DESCRIPTION

Tumor blocks from 40 patients with progressive thyroid cancer despite standard-of-care therapy were screened for PPFP, and the tumor from only one patient (2.5%) was positive. The patient had a 6.0-cm acetabular soft tissue metastasis from Hürthle cell carcinoma that caused severe pain on weight bearing and had a serum thyroglobulin level of 1974 ng/mL. After 24 weeks of therapy with pioglitazone, the metastatic lesion was 3.9 cm, the thyroglobulin level was 49.4 ng/mL, and the patient was pain-free. Thirteen months after discontinuation of pioglitazone, the metastatic lesion was 3.6 cm, the thyroglobulin level was 4.7 ng/mL, and the patient remained pain-free.

CONCLUSIONS

Pioglitazone may be therapeutic in patients with PPFP thyroid cancer. However, thyroid cancers that are progressive despite standard-of-care therapy appear to only rarely express PPFP.

Thyroid-Specific T Cells in Patients With Differentiated Thyroid Cancer: Implications for Immune-Based Therapies?

This editorial reviews the recent paper by Ehlers et al and provides a perspective on thyroid cancer immunology.

Leveraging the immune system to treat advanced thyroid cancers

Inflammation has long been associated with the thyroid and with thyroid cancers, raising seminal questions about the role of the immune system in the pathogenesis of advanced thyroid cancers. With a growing understanding of dynamic tumour-immune cell interactions and the mechanisms by which tumour cells evade antitumour immunity, the field of cancer immunotherapy has been revolutionised. In this Review, we provide evidence to support the presence of an antitumour immune response in advanced thyroid cancers linked to cytotoxic T cells and NK cells. This antitumour response, however, is likely blunted by the presence of immunosuppressive pathways within the microenvironment, facilitated by tumour-associated macrophages or increased expression of negative regulators of cytotoxic T-cell function. Current and future efforts to incorporate immune-based therapies into existing tumour cell or endothelial-derived therapies-eg, with kinase inhibitors targeting tumour-associated macrophages or antibodies blocking negative regulators on T cells-could provide improved and durable responses for patients with disease that is otherwise refractory to treatment.

American Thyroid Association Guidelines on the Management of Thyroid Nodules and Differentiated Thyroid Cancer Task Force Review and Recommendation on the Proposed Renaming of Encapsulated Follicular Variant Papillary Thyroid Carcinoma Without Invasion to Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features

American Thyroid Association (ATA) leadership asked the ATA Thyroid Nodules and Differentiated Thyroid Cancer Guidelines Task Force to review, comment on, and make recommendations related to the suggested new classification of encapsulated follicular variant papillary thyroid carcinoma (eFVPTC) without capsular or vascular invasion to noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP). The task force consists of members from the 2015 guidelines task force with the recusal of three members who were authors on the paper under review. Four pathologists and one endocrinologist were added for this specific review. The manuscript proposing the new classification and related literature were assessed. It is recommended that the histopathologic nomenclature for eFVPTC without invasion be reclassified as a NIFTP, given the excellent prognosis of this neoplastic variant. This is a weak recommendation based on moderate-quality evidence. It is also noted that prospective studies are needed to validate the observed patient outcomes (and test performance in predicting thyroid cancer outcomes), as well as implications on patients' psychosocial health and economics.

ADVERSE EVENT REPORTING IN PATIENTS TREATED WITH THYROID HORMONE EXTRACT

OBJECTIVE

Thyroid hormone extract is used for the treatment of thyroid disorders, but limited data exist on adverse events commonly noted by the physicians associated with this use. The purpose of this survey was to report adverse events observed by expert physicians managing patients treated for thyroid disease with thyroid hormones.

METHODS

Members of the American Thyroid Association, The Endocrine Society, and the American Association of Clinical Endocrinologists developed a survey instrument modeled on the U.S. Food and Drug Administration (FDA)'s reported adverse events for levothyroxine that would effectively assess the clinical experience of frequent prescribers of thyroid hormone. Survey links were emailed to physicians, and the websites of each society provided links to the data collection form.

RESULTS

A total of 174 reports of adverse events occurring in patients on thyroid hormone extract were received. Ninety-one of these reports were accompanied by alterations in thyrotropin values and were further analyzed. Of these, 62 (68%) subjects had developed new symptoms associated with altered thyroid-stimulating hormone (TSH). A majority of TSH changes and symptoms described were consistent with thyrotoxicosis (65%), and 2 patients had developed arrhythmias. Reporters noted difficulty in dose adjustment by primary care providers due to confusion in interpreting thyroid function test results while on thyroid extract, which often necessitated subspecialty referrals.

CONCLUSION

These adverse event reports should stimulate consideration by the FDA to regulate and monitor thyroid hormone extract use and consider standardizing these extracts to meet current standards of manufacture, hormone content, availability, and shelf-life, like the rigor with which preparations such as levothyroxine are monitored.

ABBREVIATIONS

AE = adverse event ATA = American Thyroid Association FDA = Food and Drug Administration LT3 = liothyronine LT4 = levothyroxine PTF = Pharmacovigilance Task Force T3 = triiodothyronine TSH = thyroid-stimulating hormone.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: What is new and what has changed?

Thyroid nodules are very common, and thyroid cancer is currently the fifth leading cancer diagnosis in women. The American Thyroid Association has led the development and revision of guidelines for the management of patients with thyroid nodules and differentiated thyroid cancer (DTC). The most current revision was published in the January 2016 issue of the journal Thyroid. The current guidelines have 101 recommendations, with 8 figures and 17 tables that are hopefully helpful to those treating patients with thyroid nodules and cancer. The primary goals of the American Thyroid Association Guidelines Task Force were to use the current evidence to guide recommendations and yet be as helpful and practical as possible within the scope and strength of the evidence. The current review focuses on new and significantly revised recommendations that may very well change clinical practice. The author notes 3 new basic principles that have emerged in this guidelines revision: 1) the management of thyroid nodules, including the decision to perform a fine-needle aspiration biopsy as well as follow-up decision making, will be heavily influenced by the newly developed sonographic risk pattern; 2) the long-term management of DTC along with thyroid-stimulating hormone target goals will be heavily influenced by the 4 categories of "response to therapy"; and 3) the management of patients with radioactive iodine-refractory DTC will be divided into 4 basic decision-making groups: patients who should undergo monitoring, patients who should undergo directed therapies, patients who should undergo systemic therapies, and patients who should be offered entry into clinical trials. Cancer 2017;123:372-381. © 2016 American Cancer Society.

Integrating heterogeneous drug sensitivity data from cancer pharmacogenomic studies

The consistency of in vitro drug sensitivity data is of key importance for cancer pharmacogenomics. Previous attempts to correlate drug sensitivities from the large pharmacogenomics databases, such as the Cancer Cell Line Encyclopedia (CCLE) and the Genomics of Drug Sensitivity in Cancer (GDSC), have produced discordant results. We developed a new drug sensitivity metric, the area under the dose response curve adjusted for the range of tested drug concentrations, which allows integration of heterogeneous drug sensitivity data from the CCLE, the GDSC, and the Cancer Therapeutics Response Portal (CTRP). We show that there is moderate to good agreement of drug sensitivity data for many targeted therapies, particularly kinase inhibitors. The results of this largest cancer cell line drug sensitivity data analysis to date are accessible through the online portal, which serves as a platform for high power pharmacogenomics analysis.

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.

Laryngeal examination in thyroid and parathyroid surgery: An American Head and Neck Society consensus statement: AHNS Consensus Statement

This American Head and Neck Society (AHNS) consensus statement discusses the techniques of laryngeal examination for patients undergoing thyroidectomy and parathyroidectomy. It is intended to help guide all clinicians who diagnose or manage adult patients with thyroid disease for whom surgery is indicated, contemplated, or has been performed. This consensus statement concludes that flexible transnasal laryngoscopy is the optimal laryngeal examination technique, with other techniques including laryngeal ultrasound and stroboscopy being useful in selected scenarios. © 2016 Wiley Periodicals, Inc. Head Neck 38: 811-819, 2016.

Ultrasound-based clinical prediction rule model for detecting papillary thyroid cancer in cervical lymph nodes: A pilot study

PURPOSE

To identify sonographic features of cervical lymph nodes (LNs) that are associated with papillary thyroid cancer (PTC) and to develop a prediction model for classifying nodes as metastatic or benign.

METHODS

This retrospective study included the records of postthyroidectomy patients with PTC who had undergone cervical ultrasound and LN biopsy. LN location, size, shape, hilum, echopattern, Doppler flow, and microcalcifications were assessed. Model selection was used to identify features associated with malignant LNs and to build a predictive, binary-outcome, generalized linear mixed model. A cross-validated receiver operating characteristic analysis was conducted to assess the accuracy of the model for classifying metastatic nodes.

RESULTS

We analyzed records from 71 LNs (23 metastatic) in 44 patients (16 with PTC). The predictive model included a nonhomogeneous echopattern (odds ratio [OR], 5.73; 95% confidence interval [CI], 1.07-30.74; p = 0.04), microcalcifications (OR, 4.91; 95% CI, 0.91-26.54; p = 0.06), and volume (OR, 2.57; 95% CI, 0.66-9.99; p = 0.16) as predictors. The model had an area under the curve of 0.74 (95% CI, 0.60-0.85), sensitivity of 65% (95% CI, 50% to 78%), and specificity of 85% (95% CI, 73% to 94%) at the Youden optimal cut point of 0.38.

CONCLUSIONS

Nonhomogeneous echopattern, microcalcifications, and node volume were predictive of malignant LNs in patients with PTC. A larger sample is needed to validate this model.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Reassessing the NTCTCS Staging Systems for Differentiated Thyroid Cancer, Including Age at Diagnosis

BACKGROUND

Thyroid cancer is unique for having age as a staging variable. Recently, the commonly used age cut-point of 45 years has been questioned.

OBJECTIVE

This study assessed alternate staging systems on the outcome of overall survival, and compared these with current National Thyroid Cancer Treatment Cooperative Study (NTCTCS) staging systems for papillary and follicular thyroid cancer.

METHODS

A total of 4721 patients with differentiated thyroid cancer were assessed. Five potential alternate staging systems were generated at age cut-points in five-year increments from 35 to 70 years, and tested for model discrimination (Harrell's C-statistic) and calibration (R(2)). The best five models for papillary and follicular cancer were further tested with bootstrap resampling and significance testing for discrimination.

RESULTS

The best five alternate papillary cancer systems had age cut-points of 45-50 years, with the highest scoring model using 50 years. No significant difference in C-statistic was found between the best alternate and current NTCTCS systems (p = 0.200). The best five alternate follicular cancer systems had age cut-points of 50-55 years, with the highest scoring model using 50 years. All five best alternate staging systems performed better compared with the current system (p = 0.003-0.035). There was no significant difference in discrimination between the best alternate system (cut-point age 50 years) and the best system of cut-point age 45 years (p = 0.197).

CONCLUSIONS

No alternate papillary cancer systems assessed were significantly better than the current system. New alternate staging systems for follicular cancer appear to be better than the current NTCTCS system, although they require external validation.

Long-Term Outcomes Following Therapy in Differentiated Thyroid Carcinoma: NTCTCS Registry Analysis 1987-2012

CONTEXT

Initial treatments for patients with differentiated thyroid cancer are supported primarily by single-institution, retrospective studies, with limited follow-up and low event rates. We report updated analyses of long-term outcomes after treatment in patients with differentiated thyroid cancer.

OBJECTIVE

The objective was to examine effects of initial therapies on outcomes.

DESIGN/SETTING

This was a prospective multi-institutional registry.

PATIENTS

A total of 4941 patients, median follow-up, 6 years, participated.

INTERVENTION

Interventions included total/near-total thyroidectomy (T/NTT), postoperative radioiodine (RAI), and thyroid hormone suppression therapy (THST).

MAIN OUTCOME MEASURE

Main outcome measures were overall survival (OS) and disease-free survival using product limit and proportional hazards analyses.

RESULTS

Improved OS was noted in NTCTCS stage III patients who received RAI (risk ratio [RR], 0.66; P = .04) and stage IV patients who received both T/NTT and RAI (RR, 0.66 and 0.70; combined P = .049). In all stages, moderate THST (TSH maintained subnormal-normal) was associated with significantly improved OS (RR stages I-IV: 0.13, 0.09, 0.13, 0.33) and disease-free survival (RR stages I-III: 0.52, 0.40, 0.18); no additional survival benefit was achieved with more aggressive THST (TSH maintained undetectable-subnormal). This remained true, even when distant metastatic disease was diagnosed during follow-up. Lower initial stage and moderate THST were independent predictors of improved OS during follow-up years 1-3.

CONCLUSIONS

We confirm previous findings that T/NTT followed by RAI is associated with benefit in high-risk patients, but not in low-risk patients. In contrast with earlier reports, moderate THST is associated with better outcomes across all stages, and aggressive THST may not be warranted even in patients diagnosed with distant metastatic disease during follow-up. Moderate THST continued at least 3 years after diagnosis may be indicated in high-risk patients.

Targeting the NF-κB Pathway as a Combination Therapy for Advanced Thyroid Cancer

NF-κB signaling plays an important role in tumor cell proliferation, cell survival, angiogenesis, invasion, metastasis and drug/radiation resistance. Combination therapy involving NF-κB pathway inhibition is an attractive strategy for the treatment of advanced forms of thyroid cancer. This study was designed to test the efficacy of NF-κB pathway inhibition in combination with cytotoxic chemotherapy, using docetaxel and ionizing radiation in in vitro models of thyroid cancer. We found that while both docetaxel and ionizing radiation activated NF-κB signaling in thyroid cancer cells, there was no synergistic effect on cell proliferation and/or programmed cell death with either genetic (transduction of a dominant negative mutant form of IκBα) or pharmacologic (proteasome inhibitor bortezomib and IKKβ inhibitor GO-Y030) inhibition of the NF-κB pathway in thyroid cancer cell lines BCPAP, 8505C, THJ16T and SW1736. Docetaxel plus bortezomib synergistically decreased in vitro invasion of 8505C cells, but not in the other cell lines. Screening of a panel of clinically relevant targeted therapies for synergy with genetic NF-κB inhibition in a proliferation/cytotoxicity assay identified the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) as a potential candidate. However, the synergistic effect was confirmed only in the BCPAP cells. These results indicate that NF-κB inhibitors are unlikely to be beneficial as combination therapy with taxane cytotoxic chemotherapy, external radiation therapy or radioiodine therapy. There may be unique circumstances where NF-κB inhibitors may be considered in combination with docetaxel to reduce tumor invasion or in combination with HDAC inhibitors to reduce tumor growth, but this does not appear to be a combination therapy that could be broadly applied to patients with advanced thyroid cancer. Further research may identify which subsets of patients/tumors may respond to this therapeutic approach.

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.

Development and characterization of six new human papillary thyroid carcinoma cell lines

CONTEXT

Cell lines are a widely used tool in cancer research. However, despite the relatively high incidence of papillary thyroid carcinoma (PTC), there are only four PTC cell lines available for international research audience.

OBJECTIVE

The objective of this study was to establish and characterize new PTC cell lines that represent primary tumor biology. Surgical specimens were obtained to generate PTC cell lines. Short tandem repeat profiling was used to confirm the uniqueness of the cell lines against databases of known cell lines and mutations were assessed using Sequenom. The expression of thyroid-specific genes was examined using real-time PCR. Tumorigenicity was determined using an orthotopic thyroid xenograft tumor mouse model.

RESULTS

Six PTC cell lines (five conventional PTCs and one follicular variant of PTC) were generated and found to be unique when compared by short tandem repeat profiling against databases of all existing cell lines. The five conventional PTC cell lines carry the BRAF V600E mutation and the follicular variant of PTC cell line had an NRAS mutation. Five of the six cell lines had a mutation in the promoter of the human telomerase reverse transcriptase gene. None of the cell lines have RET/PTC rearrangements. Three cell lines were tumorigenic in the orthotopic thyroid xenograft tumor mouse model.

CONCLUSIONS

These five characterized conventional PTC cell lines and the unique follicular variant of PTC cell line should be valuable reagents for thyroid cancer research. The three tumorigenic cell lines can be used for in vivo testing of targeted therapeutic and novel agents.