Rates of Malignancy in Cytology Indeterminate Thyroid Nodules: A Single Center Surgical Series.

BACKGROUND: Due to the high variability in malignancy rate among cytologically indeterminate thyroid nodules (Bethesda categories III-V), the American Thyroid Association recommends that each center define its own categorical cancer risk. OBJECTIVES: To assess cancer risk in patients with cytologically indeterminate thyroid nodules who were operated at our center. METHODS: In a retrospective study, we analyzed the pathology results of all the patients whose fine needle aspiration results showed Bethesda III-V cytology and who subsequently underwent total thyroidectomy or lobectomy from December 2013 to September 2017. RESULTS: We analyzed 56 patients with indeterminate cytology on fine needle aspiration. Twenty-nine (52%) were defined as Bethesda III, 19 (34%) Bethesda IV, and 8 (14%) Bethesda V category. Malignancy rates were 38%, 58%, and 100% for Bethesda categories III, IV, and V, respectively. Most malignancies in Bethesda categories III and IV were follicular in origin (follicular thyroid carcinoma and follicular type papillary thyroid carcinoma), while 100% of the patients with Bethesda category V were diagnosed with classical papillary thyroid carcinoma. No correlation was found between sonographic and cytological criteria of nodules with Bethesda categories III and IV and rates of malignancy. CONCLUSIONS: We found higher than expected rates of malignancy in indeterminate cytology. This finding reinforces the guidelines of the American Thyroid Association to establish local malignancy rates for thyroid nodules with indetermined cytology.

Ivabradine for Uncontrolled Sinus Tachycardia in Thyrotoxic Cardiomyopathy - Case Report.

BACKGROUND: Beta-blockers, mainly propranalol, are usually administered to control heart rate in patients with thyrotoxicosis, especially when congestive heart failure presents. However, when thyrotoxicosis is not controlled, heart rate may be difficult to control even with maximal doses of propranolol. This presentation alerts physicians to the possibility of using ivabradine, a selective inhibitor of the sinoatrial pacemaker, for the control of heart rate. CASE PRESENTATION: We present a 37-year-old woman with thyrotoxicosis and congestive heart failure whose heart rate was not controlled with a maximal dose of beta blockers during a thyroid storm. The addition of ivabradine, a selective inhibitor of the sinoatrial pacemaker, controlled her heart rate within 48 hours. CONCLUSION: Ivabradine should be considered in patients with thyrotoxicosis, including those with heart failure, in whom beta blockers are insufficient to control heart rate.

Thyroglobulin is a poor predictor of differentiated thyroid cancer in patients who undergo surgery for thyroid nodular diseases.

OBJECTIVES: Thyroglobulin, produced exclusively by thyroid follicular cells, serves as a specific tumor marker for the follow-up of differentiated thyroid cancer (DTC) patients after thyroidectomy. However, its role as a predictor of malignancy in patients with thyroid nodules is controversial. We assessed the potential role of preoperative serum thyroglobulin concentration to predict DTC in patients without a preoperative diagnosis of malignancy who underwent partial or total thyroidectomy. METHODS: This retrospective study included patients with a preoperative diagnosis of benign multinodular goiter (MNG) or a thyroid nodule with indeterminate cytology (INC) (Bethesda system categories III/IV) who underwent partial or total thyroidectomy between January 2014 and May 2019. We compared the patients' demographic, clinical, imaging, and biochemical data according to their final diagnosis: DTC or benign thyroid nodular disease. Further statistical analysis included odds ratio calculation and receiver operating characteristic (ROC) curve analysis. RESULTS: Of 131 patients who met inclusion and exclusion criteria, the indication for surgery was benign MNG in 69 patients and a thyroid nodule with INC in 62 patients. A final diagnosis of DTC was reported in 18 of the 69 benign MNG patients (26%) and in 30 of the 62 thyroid nodule with INC patients (48%). The preoperative measurements of nodule diameter and serum thyroid-stimulating hormone and thyroglobulin concentrations did not significantly differ between patients with a final diagnosis of DTC and those with benign histology. CONCLUSIONS: Preoperative serum thyroglobulin alone is insufficient to differentiate between malignant and benign thyroid nodular disease.

Safety and long-term efficacy of tonsillectomy versus subtotal tonsillectomy in children with sleep disordered breathing.

OBJECTIVES: to compare safety and long-term symptoms after TE compared to Subtotal Tonsillectomy (STT). METHODS: A retrospective review data of 412 patients, one to twelve years old that underwent either TE or STT, as treatment for sleep disorder breathing, at two different medical centers. Symptoms were assessed by a questionnaire 3-5 years post-surgery. Additionally, data regarding immediate post-operative symptoms and complications were also collected. RESULTS: Long-term symptoms score was significantly lower in the TE group: 1.585 (±1.719) compared to 1.967 (±1.815) in the STT group (p = 0.033); 51.3% of patients in the ST group presented long-term SDB symptoms, compared to 40.6% in the TE group (p = 0.035); The main difference between the groups was snoring as 49% of the STT group suffered from snoring, versus 28.9% in the TE group (p < 0.001). CONCLUSIONS: TE showed an advantage over STT in resolving snoring in the long term.

MEK1/2 inhibition transiently alters the tumor immune microenvironment to enhance immunotherapy efficacy against head and neck cancer.

BACKGROUND: Although the mitogen-activated protein kinases (MAPK) pathway is hyperactive in head and neck cancer (HNC), inhibition of MEK1/2 in HNC patients has not shown clinically meaningful activity. Therefore, we aimed to characterize the effect of MEK1/2 inhibition on the tumor microenvironment (TME) of MAPK-driven HNC, elucidate tumor-host interaction mechanisms facilitating immune escape on treatment, and apply rationale-based therapy combination immunotherapy and MEK1/2 inhibitor to induce tumor clearance. METHODS: Mouse syngeneic tumors and xenografts experiments were used to analyze tumor growth in vivo. Single-cell cytometry by time of flight, flow cytometry, and tissue stainings were used to profile the TME in response to trametinib (MEK1/2 inhibitor). Co-culture of myeloid-derived suppressor cells (MDSC) with CD8+ T cells was used to measure immune suppression. Overexpression of colony-stimulating factor-1 (CSF-1) in tumor cells was used to show the effect of tumor-derived CSF-1 on sensitivity to trametinib and anti-programmed death- 1 (αPD-1) in mice. In HNC patients, the ratio between CSF-1 and CD8A was measured to test the association with clinical benefit to αPD-1 and αPD-L1 treatment. RESULTS: Using preclinical HNC models, we demonstrated that treatment with trametinib delays HNC initiation and progression by reducing tumor cell proliferation and enhancing the antitumor immunity of CD8+ T cells. Activation of CD8+ T cells by supplementation with αPD-1 antibody eliminated tumors and induced an immune memory in the cured mice. Mechanistically, an early response to trametinib treatment sensitized tumors to αPD-1-supplementation by attenuating the expression of tumor-derived CSF-1, which reduced the abundance of two CSF-1R+CD11c+ MDSC populations in the TME. In contrast, prolonged treatment with trametinib abolished the antitumor activity of αPD-1, because tumor cells undergoing the epithelial to mesenchymal transition in response to trametinib restored CSF-1 expression and recreated an immune-suppressive TME. CONCLUSION: Our findings provide the rationale for testing the trametinib/αPD-1 combination in HNC and highlight the importance of sensitizing tumors to αPD-1 by using MEK1/2 to interfere with the tumor-host interaction. Moreover, we describe the concept that treatment of cancer with a targeted therapy transiently induces an immune-active microenvironment, and supplementation of immunotherapy during this time further activates the antitumor machinery to cause tumor elimination.

Assessment of parathyroid gland cellularity by digital slide analysis.

BACKGROUND: Computer-aided examination of digital tissue images has attracted attention in recent years. Application in the field of parathyroid pathology has not been studied previously. It holds a potential to assist in the examination of parathyroid gland adenoma or hyperplasia. OBJECTIVES: To explore parathyroid cell detection of slide images by digital tissue analysis and compare the results to standard human processing. METHODS: 47 incisional biopsies of healthy appearing parathyroid glands were evaluated for their cellularity level. First, by the standard examination using microscopy by three independent pathologists. We compared the mean cellularity grading of the pathologists to the output of a computerized cell detection software. RESULTS: A disagreement was found between the standard human cellularity grading and the digital analysis output. However, the digital analysis reaches a 94% specificity and 48% sensitivity to predict high cellularity (>60% parenchymal cells). CONCLUSIONS: Digital analysis of parathyroid tissue can be used as a tool for hypercellularity elimination, therefore assisting in the diagnosis of parathyroid cell hyperplasia. Additional studies using more advanced algorithms are necessary for further precision enhancement.

High parathyroid hormone levels after parathyroidectomy for parathyroid adenoma are not related to the cellularity of the remaining glands.

BACKGROUND: Patients with primary hyperparathyroidism (PHPT) treated surgically occasionally have normalized calcium, but persistently high parathyroid hormone (PTH). We hypothesized that a possible explanation for this phenomenon is an underlying hyperplasia rather than adenoma. METHODS: Retrospective cohort of patients who underwent parathyroidectomy for PHPT with biopsy of a normal-appearing parathyroid gland were included. Cellularity level of each biopsy and of the adenoma's rim was determined. RESULTS: Forty-seven patients were included. Of them, 19 (40%) had postoperative normocalcemia but elevated PTH. There was no correlation between cellularity either in the rim or of the normal-appearing parathyroid gland and postoperative PTH. The postoperative high PTH group had higher preoperative PTH (P = 0.001) and larger adenomas (P = 0.025). CONCLUSIONS: High PTH levels after successful parathyroidectomy in patients with primary hyperparathyroidism do not appear to result from underlying hyperplasia. A possible alternative explanation is that these patients have a higher preoperative burden of disease.

Treatment Modality and Second Primary Tumors of the Head and Neck.

INTRODUCTION: Second primary tumors (SPTs) in head and neck cancer are thought to occur from premalignant lesions that are present at the time of the primary tumor diagnosis. The association of the modality used to treat the primary lesion with SPT occurrence is not clear. OBJECTIVE: The aim of the study was to assess the incidence of SPTs in patients with head and neck malignancies, according to treatment modality. METHODS: We conducted a retrospective cohort study. All patients who were treated at Soroka Medical Center between 2000 and 2013 for a head and neck squamous cell carcinoma were assessed. Data analysis included tumor site of the primary and second primary and treatment modality of the primary tumor. In addition, demographics as well as habits were recorded as well. RESULTS: Of the 184 patients included in the cohort, SPT developed in 31 patients (17%) with a median time to diagnosis of 4.3 years. Smoking was reported in 74% of those with SPT and 78% of those without. The most common site for SPT was the lungs, with 13 cases, 42% of the total SPTs. Among patients who developed an SPT, for 12 of those with an index tumor in the oral cavity or oro-hypopharynx, 8 (67%) developed an SPT in the same location; for 18 of those with an index tumor in the larynx, 11 (61%) developed a SPT in the lungs and bronchi (p = 0.001). On multivariate analysis, the treatment modality used was not found to be associated with the occurrence of SPTs and the radiotherapy showed no protective or harmful effect (HR 0.64 p = 0.24). CONCLUSION: Treatment modality used for head and neck cancer does not seem to be associated with the occurrence of SPTs.

WITHDRAWN: Ivabradine for Uncontrolled Sinus Tachycardia in Thyrotoxic Cardiomyopathy ­ Case Report

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IGF2 Mediates Resistance to Isoform-Selective-Inhibitors of the PI3K in HPV Positive Head and Neck Cancer.

Over 50% of human papilloma positive head-and-neck cancer (HNCHPV+) patients harbor genomic-alterations in PIK3CA, leading to hyperactivation of the phosphatidylinositol-4, 5-bisphosphate 3-kinase (PI3K) pathway. Nevertheless, despite PI3K pathway activation in HNCHPV+ tumors, the anti-tumor activities of PI3K pathway inhibitors are moderate, mostly due to the emergence of resistance. Thus, for potent and long-term tumor management, drugs blocking resistance mechanisms should be combined with PI3K inhibitors. Here, we delineate the molecular mechanisms of the acquisition of resistance to two isoform-selective inhibitors of PI3K (isiPI3K), alpelisib (BYL719) and taselisib (GDC0032), in HNCHPV+ cell lines. By comparing the transcriptional landscape of isiPI3K-sensitive tumor cells with that of their corresponding isiPI3K-acquired-resistant tumor cells, we found upregulation of insulin growth factor 2 (IGF2) in the resistant cells. Mechanistically, we show that upon isiPI3K treatment, isiPI3K-sensitive tumor cells upregulate the expression of IGF2 to induce cell proliferation via the activation of the IGF1 receptor (IGF1R). Stimulating tumor cells with recombinant IGF2 limited isiPI3K efficacy and released treated cells from S phase arrest. Knocking-down IGF2 with siRNA, or blocking IGF1R with AEW541, resulted in superior anti-tumor activity of isiPI3K in vitro and ex vivo. In vivo, the combination of isiPI3K and IGF1R inhibitor induced stable disease in mice bearing either tumors generated by the HNCHPV+ UM-SCC47 cell line or HPV+ patient-derived xenografts. These findings indicate that IGF2 and the IGF2/IGF1R pathway may constitute new targets for combination therapies to enhance the efficacy of PI3K inhibitors for the treatment of HNCHPV+.

Thyroid malignancy rates according to the Bethesda reporting system in Israel - A multicenter study.

INTRODUCTION: The Bethesda System for Reporting Thyroid Cytopathology was developed in 2007 to facilitate an accurate, reproducible communication of thyroid fine-needle aspiration (FNA) interpretations between clinicians and cytopathologists and to serve as a guide for treatment. Based on large patient series, the system details the risk of malignancy for each category as well as a suggested management for each FNA result. Though this system has been widely adopted, there are only few studies to determine whether results are applicable for Israel. METHODS: A multicenter, retrospective analysis of medical charts of all patients who underwent thyroid surgery between January 1st, 2012 and December 31st, 2016 in four medical centers in Israel was performed. Data was analyzed for the overall risk of malignancy for the Bethesda system groups as well as comparison between the different laboratories performing the test. RESULTS: Records of 810 thyroidectomies in which preoperative cytological reports and final pathology were available and reviewed. The malignancy rates according to the Bethesda groups' I-VI for our cohort were: 27.8%, 17.6%, 41.4%, 41.4%, 86.9%, and 98.1% respectively. Similar results were seen when results were analyzed according to the different laboratories performing the tests. CONCLUSIONS: Post-surgical review of all Bethesda groups had higher malignancy rates than those reported in the original report. These results indicate a difference in the malignancy rates for the different Bethesda system groups in Israel compared to those reported. Physicians are encouraged to use data validated for their own country or patients' community in addition to published values.

CDK 4/6 Inhibition Overcomes Acquired and Inherent Resistance to PI3Kα Inhibition in Pre-Clinical Models of Head and Neck Squamous Cell Carcinoma.

Activating alterations in PIK3CA, the gene coding for the catalytic subunit of phosphoinositide-3-kinase (PI3K), are prevalent in head and neck squamous cell carcinoma (HNSCC) and thought to be one of the main drivers of these tumors. However, early clinical trials on PI3K inhibitors (PI3Ki) have been disappointing due to the limited durability of the activity of these drugs. To investigate the resistance mechanisms to PI3Ki and attempt to overcome them, we conducted a molecular-based study using both HNSCC cell lines and patient-derived xenografts (PDXs). We sought to simulate and dissect the molecular pathways that come into play in PIK3CA-altered HNSCC treated with isoform-specific PI3Ki (BYL719, GDC0032). In vitro assays of cell viability and protein expression indicate that activation of the mTOR and cyclin D1 pathways is associated with resistance to PI3Ki. Specifically, in BYL719-resistant cells, BYL719 treatment did not induce pS6 and pRB inhibition as detected in BYL719-sensitive cells. By combining PI3Ki with either mammalian target of rapamycin complex 1 (mTORC1) or cyclin D1 kinase (CDK) 4/6 specific inhibitors (RAD001 and abemaciclib, respectively), we were able to overcome the acquired resistance. Furthermore, we found that PI3Ki and CDK 4/6 inhibitors have a synergistic anti-tumor effect when combined in human papillomavirus (HPV)-negative/PIK3CA-WT tumors. These findings provide a rationale for combining PI3Ki and CDK 4/6 inhibitors to enhance anti-tumor efficacy in HNSCC patients.

Trauma-induced vestibular dysfunction: Possible functional repair under α1-antitrypsin-rich conditions.

Transient vestibular organ deafferentation, such that is caused by traumatic tissue injury, is presently addressed by corticosteroid therapy. However, restoration of neurophysiological properties is rarely achieved. Here, it was hypothesized that the tissue-protective attributes of α1-antityrpsin (AAT) may promote restoration of neuronal function. Inner ear injury was inflicted by unilateral labyrinthotomy in wild-type mice and in mice overexpressing human AAT. A 2-week-long assessment of vestibular signs followed. All animals responded with peak vestibular dysfunction scores within 4 h after local trauma. While wild-type animals displayed partial or no recovery across 7 days post-injury, AAT-rich group exhibited early recovery: from behavioral score 9-out-of-9 at peak to 4.8 ±â€¯0.44 (mean ±â€¯SD) within 8 h from injury, a time when wild-type mice scored 8.6 ±â€¯0.54 (p < 0.0001), and from vestibular score 15-out-of-15 to 7.8 ±â€¯2.2 within 24 h, when wild-type mice scored 13.0 ±â€¯2.0 (p < 0.01). Thus, recovery and functional normalisation of an injured vestibular compartment is achievable without corticosteroid therapy; expedited tissue repair processes appear to result from elevated circulating AAT levels. This study lays the foundation for exploring the molecular and cellular mediators of AAT within the repair processes of the delicate microscopic structures of the vestibular end organ.

Limitations of ultrasound in predicting bilaterality vs unilaterality of well-differentiated carcinoma of the thyroid.

PURPOSE: The purpose of this study is to assess the efficacy of ultrasonography in the differentiation of a bilateral and a unilateral WDTC to help physicians decide on performing a total or a partial thyroidectomy. MATERIALS AND METHODS: Retrospective chart review of all patients diagnosed with papillary thyroid carcinoma following a total thyroidectomy or a complete thyroidectomy between January 2013 and December 2015 at the Department of Otorhinolaryngology and Head and Neck Surgery in Soroka University Medical Center in southern Israel. The preoperative ultrasound images of the thyroid were compared to the final pathology in the contralateral lobe. RESULTS: Seventy seven patients (77) were included in this study, There was no correlation between the sonography in the contralateral lobe and the malignancy on that side (p = 0.479). US had a 39% false negative rate and 69% false positive rate. CONCLUSION: The patients with a well-differentiated carcinoma of the thyroid, a benign nodule detected sonographically in the contralateral lobe should not bear a high weight in decision making regarding the extent of surgery.

Endogenous α1-antitrypsin levels in the perilymphatic fluid correlates with severity of hearing loss.

OBJECTIVES: To determine the levels of endogenous α1-antitrypsin in the perilymph of patients undergoing cochlear implant (CI), and its reverse association with the severity of hearing loss. STUDY DESIGN: Retrospective study. SETTING: Tertiary care university hospital. PARTICIPANTS: The study includes 38 patients undergoing CI surgery, 11 patients diagnosed with congenital deafness and 27 non-congenital deafness, eight patients diagnosed with moderate hearing loss (N = 8; PTA = 70 dB), severe hearing loss (N = 11; PTA 70-90 dB) and profound hearing loss (N = 19; PTA > 90 dB). MAIN OUTCOME AND MEASURE: 1 to 12 µL perilymphatic fluids were collected by micropipette. α1-antitrypsin levels were determined, and current and historic audiological parameters were obtained. RESULTS: The congenital and non-congenital group exhibited AAT concentrations of 2.5 ± 1.9 × 106 LFQ and 3.2 ± 1.2 × 106 LFQ, respectively (mean ± SD; P = .38). Mean levels of α1-antitrypsin in the perilymph fluid within the moderate group was 3.64 × 106  ± 2.1 × 106 LFQ vs 3.5 × 106  ± 1.2 × 106 in severe hearing loss (P = .81) and 2.4 × 106  ± 1.1 × 106 LFQ in the profound hearings loss group (P = .06). The difference in levels of AAT in samples from the severe hearings loss group vs the profound hearings loss group reached statistical significance (P = .04). CONCLUSION: Insufficiency in α1-antitrypsin levels in the perilymph fluid of the inner ear appears to display a relationship with the severity of hearing loss. The prospect of introducing clinical-grade plasma-purified α1-antitrypsin directly onto the site of cochlear injury deserves thorough investigation.

TGF-Beta-Activated Cancer-Associated Fibroblasts Limit Cetuximab Efficacy in Preclinical Models of Head and Neck Cancer.

Most head and neck cancer (HNC) patients are resistant to cetuximab, an antibody against the epidermal growth factor receptor. Such therapy resistance is known to be mediated, in part, by stromal cells surrounding the tumor cells; however, the mechanisms underlying such a resistance phenotype remain unclear. To identify the mechanisms of cetuximab resistance in an unbiased manner, RNA-sequencing (RNA-seq) of HNC patient-derived xenografts (PDXs) was performed. Comparing the gene expression of HNC-PDXs before and after treatment with cetuximab indicated that the transforming growth factor-beta (TGF-beta) signaling pathway was upregulated in the stromal cells of PDXs that progressed on cetuximab treatment (CetuximabProg-PDX). However, in PDXs that were extremely sensitive to cetuximab (CetuximabSen-PDX), the TGF-beta pathway was downregulated in the stromal compartment. Histopathological analysis of PDXs showed that TGF-beta-activation was detected in cancer-associated fibroblasts (CAFs) of CetuximabProg-PDX. These TGF-beta-activated CAFs were sufficient to limit cetuximab efficacy in vitro and in vivo. Moreover, blocking the TGF-beta pathway using the SMAD3 inhibitor, SIS3, enhanced cetuximab efficacy and prevented the progression of CetuximabProg-PDX. Altogether, our findings indicate that TGF-beta-activated CAFs play a role in limiting cetuximab efficacy in HNC.

Inhibition of the NKp44-PCNA Immune Checkpoint Using a mAb to PCNA.

mAb-based blocking of the immune checkpoints involving the CTLA4-B7 and PD1-PDL1 inhibitory axes enhance T-cell-based adaptive immune responses in patients with cancer. We show here that antitumor responses by natural killer (NK) cells can be enhanced by a checkpoint-blocking mAb, 14-25-9, which we developed against proliferating cell nuclear antigen (PCNA). PCNA is expressed on the surface of cancer cells and acts as an inhibitory ligand for the NK-cell receptor, NKp44-isoform1. We tested for cytoplasmic- and membrane-associated PCNA by FACS- and ImageStream-based staining of cell lines and IHC of human cancer formalin fixed, paraffin embedded tissues. The mAb, 14-25-9, inhibited binding of chimeric NKp44 receptor to PCNA and mostly stained the cytoplasm and membrane of tumor cells, whereas commercial antibody (clone PC10) stained nuclear PCNA. NK functions were measured using ELISA-based IFNγ secretion assays and FACS-based killing assays. The NK92-NKp44-1 cell line and primary human NK cells showed increased IFNγ release upon coincubation with mAb 14-25-9 and various solid tumor cell lines and leukemias. Treatment with 14-25-9 also increased NK cytotoxic activity. In vivo efficacy was evaluated on patient-derived xenografts (PDX)-bearing NSG mice. In PDX-bearing mice, intravenous administration of mAb 14-25-9 increased degranulation (CD107a expression) of intratumorally injected patient autologous or allogeneic NK cells, as well as inhibited tumor growth when treated long term. Our study describes a mAb against the NKp44-PCNA innate immune checkpoint that can enhance NK-cell antitumor activity both in vitro and in vivo.

Repression of AXL expression by AP-1/JNK blockage overcomes resistance to PI3Ka therapy.

AXL overexpression is a common resistance mechanism to anti-cancer therapies, including the resistance to BYL719 (Alpelisib) - the p110α isoform specific inhibitor of phosphoinositide 3-kinase (PI3K) - in esophagus and head and neck squamous cell carcinoma (ESCC, HNSCC respectively). However, the mechanisms underlying AXL overexpression in resistance to BYL719 remain elusive. Here we demonstrated that the AP-1 transcription factors, c-JUN and c-FOS, regulate AXL overexpression in HNSCC and ESCC. The expression of AXL was correlated with that of c-JUN both in HNSCC patients and in HNSCC and ESCC cell lines. Silencing of c-JUN and c-FOS expression in tumor cells downregulated AXL expression and enhanced the sensitivity of human papilloma virus positive (HPVPos) and negative (HPVNeg) tumor cells to BYL719 in vitro. Blocking of the c-JUN N-terminal kinase (JNK) using SP600125 in combination with BYL719 showed a synergistic anti-proliferative effect in vitro, which was accompanied by AXL downregulation and potent inhibition of the mTOR pathway. In vivo, the BYL719-SP600125 drug combination led to the arrest of tumor growth in cell line-derived and patient-derived xenograft models, and in syngeneic head and neck murine cancer models. Collectively, our data suggests that JNK inhibition in combination with anti-PI3K therapy is a new therapeutic strategy that should be tested in HPVPos and HPVNeg HNSCC and ESCC patients.

Tumor Tissue Explant Culture of Patient-Derived Xenograft as Potential Prioritization Tool for Targeted Therapy.

Despite of remarkable progress made in the head and neck cancer (HNC) therapy, the survival rate of this metastatic disease remain low. Tailoring the appropriate therapy to patients is a major challenge and highlights the unmet need to have a good preclinical model that will predict clinical response. Hence, we developed an accurate and time efficient drug screening method of tumor ex vivo analysis (TEVA) system, which can predict patient-specific drug responses. In this study, we generated six patient derived xenografts (PDXs) which were utilized for TEVA. Briefly, PDXs were cut into 2 × 2 × 2 mm3 explants and treated with clinically relevant drugs for 24 h. Tumor cell proliferation and death were evaluated by immunohistochemistry and TEVA score was calculated. Ex vivo and in vivo drug efficacy studies were performed on four PDXs and three drugs side-by-side to explore correlation between TEVA and PDX treatment in vivo. Efficacy of drug combinations was also ventured. Optimization of the culture timings dictated 24 h to be the time frame to detect drug responses and drug penetrates 2 × 2 × 2 mm3 explants as signaling pathways were significantly altered. Tumor responses to drugs in TEVA, significantly corresponds with the drug efficacy in mice. Overall, this low cost, robust, relatively simple and efficient 3D tissue-based method, employing material from one PDX, can bypass the necessity of drug validation in immune-incompetent PDX-bearing mice. Our data provides a potential rationale for utilizing TEVA to predict tumor response to targeted and chemo therapies when multiple targets are proposed.

MET activation confers resistance to cetuximab, and prevents HER2 and HER3 upregulation in head and neck cancer.

An understanding of the mechanisms underlying acquired resistance to cetuximab is urgently needed to improve cetuximab efficacy in patients with head and neck squamous cell carcinoma (HNSCC). Here, we present a clinical observation that MET pathway activation constitutes the mechanism of acquired resistance to cetuximab in a patient with HNSCC. Specifically, RNA sequencing and mass spectrometry analysis of cetuximab-sensitive (CetuxSen ) and cetuximab-resistant (CetuxRes ) tumors indicated MET amplification and overexpression in the CetuxRes tumor compared to the CetuxSen lesion. Stimulation of MET in HNSCC cell lines was sufficient to reactivate the MAPK pathway and to confer resistance to cetuximab in vitro and in vivo. In addition to the direct role of MET in reactivation of the MAPK pathway, MET stimulation abrogates the well-known cetuximab-induced compensatory feedback loop of HER2/HER3 expression. Mechanistically, we showed that the overexpression of HER2 and HER3 following cetuximab treatment is mediated by the ETS homologous transcription factor (EHF), and is suppressed by MET/MAPK pathway activation. Collectively, our findings indicate that evaluation of MET and HER2/HER3 in response to cetuximab in HNSCC patients can provide the rationale of successive line of treatment.