Performance of a multigene genomic classifier and clinical parameters in predicting malignancy in a Southeast Asian cohort of patients with cytologically indeterminate thyroid nodules

BACKGROUND

Most thyroid nodules are benign. It is important to determine the likelihood of malignancy in such nodules to avoid unnecessary surgery. The primary objective of this study was to characterize the genetic landscape and the performance of a multigene genomic classifier in fine-needle aspiration (FNA) biopsies of cytologically indeterminate thyroid nodules in a Southeast Asian cohort. The secondary objective was to assess the predictive contribution of clinical characteristics to thyroid malignancy.

METHODS

This prospective, multicenter, blinded study included 132 patients with 134 nodules. Molecular testing (MT) with ThyroSeq v3 was performed on clinical or ex-vivo FNA samples. Centralized pathology review also was performed.

RESULTS

Of 134 nodules, consisting of 61% Bethesda category III, 20% category IV, and 19% category V cytology, and 56% were histologically malignant. ThyroSeq yielded negative results in 37.3% of all FNA samples and in 42% of Bethesda category III-IV cytology nodules. Most positive samples had RAS-like (41.7%), followed by BRAF-like (22.6%), and high-risk (17.9%) alterations. Compared with North American patients, the authors observed a higher proportion of RAS-like mutations, specifically NRAS, in Bethesda categories III and IV and more BRAF-like mutations in Bethesda category III. The test had sensitivity, specificity, negative predictive value, and positive predictive value of 89.6%, 73.7%, 84.0%, and 82.1%, respectively. The risk of malignancy was predicted by positive MT and high-suspicion ultrasound characteristics according to American Thyroid Association criteria.

CONCLUSIONS

Even in the current Southeast Asian cohort with nodules that had a high pretest cancer probability, MT could lead to potential avoidance of diagnostic surgery in 42% of patients with Bethesda category III-IV nodules. MT positivity was a stronger predictor of malignancy than clinical parameters.

Association of comprehensive thyroid cancer molecular profiling with tumor phenotype and cancer-specific outcomes

BACKGROUND

Molecular testing improves the diagnostic accuracy of thyroid cancer. Whether specific molecular testing results are associated with tumor phenotype or provide prognostic information needs further delineation.

METHODS

Consecutive thyroid cancer patients after index thyroidectomy with ThyroSeq version 3 (Rye Brook, NY) molecular testing obtained on preoperative fine-needle aspiration or thyroidectomy specimens from patients with thyroid cancer were categorized into 3 molecular risk groups based on detected mutations, fusions, copy number alterations, and/or gene expression alterations and correlated with histopathology and recurrence, defined as biochemical or structural.

RESULTS

Of 578 patients, 49.9%, 37.5%, and 12.6% had molecular risk group-low, molecular risk group-intermediate, and molecular risk group-high cancers, respectively. With a median 19-month follow-up, 9.1% patients recurred. Compared with molecular risk group-low, molecular risk group-intermediate cancers were diagnosed in younger patients and more often had microscopic extrathyroidal extension, involved margins, and nodal disease. Compared with molecular risk group-intermediate, molecular risk group-high cancers were diagnosed in older patients and more often had gross extrathyroidal extension and vascular invasion. In multivariable analysis, recurrence was more likely in molecular risk group-high cancers than in molecular risk group-intermediate (hazard ratio = 4.0; 95% confidence interval, 1.9-8.6; P < .001) and more likely in molecular risk group-intermediate than in molecular risk group-low (hazard ratio = 5.0; 95% confidence interval, 2.0-12.5; P < .001).

CONCLUSION

Using modern comprehensive genotyping, the genetic profile of thyroid cancers can be categorized into 3 novel molecular risk groups that were associated with histopathologic phenotype and recurrence in short-term follow-up.

Performance of a Multigene Genomic Classifier in Thyroid Nodules with Suspicious for Malignancy Cytology

Background: Molecular testing is increasingly used to refine the probability of cancer and assess recurrence risk in thyroid nodules with Bethesda III/IV fine needle aspiration (FNA) cytology. However, limited data exist for Bethesda V (suspicious for malignancy [SFM]) samples. This study evaluated the performance of ThyroSeq v3 (TSv3) in thyroid nodules with SFM cytology. Methods: In this single-institution retrospective cohort study, consecutive thyroid FNA samples diagnosed as SFM with TSv3 testing and known surgical outcome were identified. Clinical, pathology, and molecular findings were reviewed. The TSv3 Cancer Risk Classifier was used to determine molecular risk groups (MRGs). For test-negative cases diagnosed as cancer/noninvasive follicular thyroid neoplasm with papillary-like nuclear features, TSv3 was performed on the resected tumors. Results: Among 128 SFM samples studied, 100 (78.1%) were TSv3 positive, and 28 (21.9%) were negative. The cancer prevalence on surgery was 82.8%. Among test-positive samples, 95% were malignant and 5% benign. Among test-negative samples, 17 (60.7%) were benign and 11 (39.3%) malignant. Overall, TSv3 had a sensitivity of 89.6% (confidence interval; CI 82.4-94.1) and a specificity of 77.3% (CI 56.6-89.9). For a cancer prevalence of 50-75% expected in SFM cytology by the Bethesda system, the negative predictive value was expected to range from 71.2% to 88.1% and the positive predictive value from 79.8% to 92.2%. Among test-positive nodules, 20% were MRG-Low (mostly RAS-like alterations), 66% MRG-Intermediate (mostly BRAF-like alterations), and 14% MRG-High. Among patients with cancer, 65 (61.3%) were American Thyroid Association low risk, 25 (23.6%) intermediate risk, and 6 (5.7%) high risk. During the mean follow-up of 51.2 months (range: <1 to 470 months), 12 (13.0%) patients had disease recurrence, which was more common in MRG-High (54.6%) compared with MRG-Intermediate (9.5%) and MRG-Low (0%) cancers (p < 0.001). Upon reexamining tumors with false-negative results, half of evaluable cases had alterations likely missed due to limiting FNA sampling, and the remainder represented low-risk tumors. Potentially targetable alterations were identified in 10 samples. Conclusions: In this large series of SFM thyroid nodules, TSv3 further improved cancer prediction and detected RAS-like, BRAF-like, high-risk, and potentially targetable alterations, all of which may inform more optimal patient management. MRGs were associated with recurrence-free survival, offering potential preoperative cancer risk stratification.

Clinicopathologic Characteristics and Postsurgical Follow-Up of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features in the Postnomenclature Revision Era

Background: Noninvasive encapsulated follicular variant papillary thyroid carcinoma (EFVPTC) was reclassified as "noninvasive follicular thyroid neoplasm with papillary-like nuclear features" (NIFTP) in 2016. Most existing studies that examined outcomes included patients managed as EFVPTC and only retrospectively reclassified as NIFTP. This is the first study to evaluate the clinicopathologic, molecular, and surveillance characteristics of patients diagnosed with NIFTP at the time of surgery and managed based on this diagnosis. Methods: We performed a retrospective cohort study of consecutive cases diagnosed as NIFTP from June 2016 to October 2021 identified from electronic medical records at a large tertiary care institution. Patients with coexisting low-risk thyroid cancers ≥1.0 cm in size or any size aggressive histology were excluded, and review of demographic, clinical, imaging, cytologic, and molecular genetic data was performed. Initial care was delivered according to existing clinical guidelines, with a consensus institutional plan for five-year follow-up after surgery. Results: Among 79 patients with 84 nodules diagnosed as NIFTP after surgery, 83.5% (66/79) were women and the mean age was 51 years (range, 21-84). Mean NIFTP size was 2.4 cm (range 0.15-8.0). On ultrasound, the majority of nodules were categorized as thyroid imaging, reporting and data system TI-RADS 3 (55.3%, 42/76), and TI-RADS 4 (36.8%, 28/76). On cytology, they were typically diagnosed as Bethesda III (69.1%, 47/68) or Bethesda IV (23.5%, 16/68). Molecular testing was performed on 62 nodules, and molecular alterations were found in 93.5% (58/62). The most common alterations identified in NIFTP were RAS mutation (75.4%, 43/57), THADA fusion (12.3%, 7/57), and BRAF^K601E mutation (7.0%, 4/57). Fifty-two (65.8%) patients underwent lobectomy and 27 (34.2%) total thyroidectomy, and no patient received completion thyroidectomy. Twenty-one patients (26.5%) had coexisting papillary or follicular microcarcinoma. None of the patients received radioiodine ablation. On a mean follow-up of 28.5 months (range, 6-69 months), no structural or biochemical recurrences were observed. Conclusions: In this large cohort of patients with NIFTP diagnosed at the time of surgery and managed typically by lobectomy with no radioiodine ablation, no evidence of tumor recurrence was identified on a limited follow-up. This finding supports indolent clinical course of NIFTP.

Definitive local therapy to head and neck squamous cell carcinoma with distant metastasis

Objectives

Data on the efficacy of including definitive local therapy to the primary site for head and neck squamous cell carcinoma (HNSCC) patients with synchronous distant metastasis are lacking. In multiple different solid tumor types, there has been benefit when using systemic therapy followed by local consolidative therapy (stereotactic ablative radiotherapy or surgery) directed at metastases. We proposed to retrospectively evaluate patients at our institution that received definitive treatment to the primary.

Methods

Single institution retrospective study evaluating 40 patients with metastatic HNSCC treated with definitive surgery (55%) or chemoradiation (45%) to the primary site from 2000 to 2020. The major endpoints were overall survival (OS) and progression‐free survival (PFS) for the total population and multiple sub‐groups. Some variables were evaluated with multiple covariates Cox model.

Results

The median PFS was 8.6 months (95% CI, 6.4–11.6), and OS was 14.2 months (95% CI, 10.9–27.5). In 28% of patients that received induction therapy, there was a twofold increase in median overall survival to 27.5 months. In the 33% of patients that received anti‐PD‐1 mAb as part of their treatment course, the median OS was significantly increased to 41.7 months (95% CI, 8.7‐NR) versus 12.1 months (95% CI, 8.4–14.4) with a 5‐year OS of 39%. Multivariate analysis for OS showed significance for age at diagnosis, use of IO, and number of metastatic sites.

Conclusion

We observed impressive survival outcomes in metastatic HNSCC patients treated with definitive local therapy to the primary site in addition to induction and/or immunotherapy. Further study is warranted.

Level of Evidence: 3.

Clinicopathologic Characteristics of Thyroid Nodules Positive for the THADA-IGF2BP3 Fusion on Preoperative Molecular Analysis

Background: Thyroid adenoma-associated (THADA)-IGF2BP3 fusions have been identified as an oncogenic event in thyroid neoplasms. However, the prevalence of this gene fusion and associated phenotypical and clinical features are not well defined. The aim of this study was to characterize thyroid nodules positive for THADA-IGF2BP3 fusions on preoperative molecular analysis, review surgical outcomes, and explore potential impact of the fusion detection on patient management. Methods: Thyroid nodules positive for THADA-IGF2BP3 fusion on ThyroSeq v3 genomic classifier (GC) testing of fine needle aspiration (FNA) (n = 30) samples from November 2017 to August 2019 were identified. Demographic and clinical data were obtained by retrospective chart review; pathology slides were re-examined. Results: Thirty nodules positive for THADA-IGF2BP3 fusion on FNA were identified, representing ∼2% of 1280 nodules that underwent molecular analysis. Of the 27 nodules with available cytology diagnosis data, 22 (81%) were diagnosed as atypia of undetermined significance, 3 (11%) as follicular neoplasm, and 1 (4%) each were benign, and suspicious for malignancy. No additional mutations or gene fusions were identified in any of the nodules. Of the 24 cases with available clinical data, 22 (92%) THADA-IGF2BP3-positive nodules were managed surgically, 14 (64%) by thyroid lobectomy, and 8 (36%) by total thyroidectomy. Of the patients who had initial lobectomy, 3 (21%) had completion surgery. On surgical pathology, 7 (32%) THADA-IGF2BP3-positive nodules were malignant (six encapsulated follicular variant papillary thyroid carcinomas (EFVPTC), one minimally infiltrative FVPTC), 10 (45%) noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP), and 5 (23%) follicular adenomas (FA). THADA-IGF2BP3-positive malignancies were intrathyroidal, without aggressive histology. Nodule size was similar between malignant nodules, NIFTP, and FA (2.6, 2.7, and 2.3 cm, respectively; p = 0.77). On limited follow-up (mean, 18 months) available for six patients with malignant fusion-positive nodule and 4 patients with NIFTP, no tumor recurrences were found. Conclusions: In this series of patients, 77% of THADA-IGF2BP3 fusion-positive thyroid nodules were thyroid tumors requiring surgery, either papillary carcinoma or NIFTP. However, all cancers were low risk, predominantly encapsulated FVPTCs and thus can likely be adequately treated with lobectomy.

Outcomes with definitive local treatment to the primary site in non-nasopharyngeal head and neck squamous cell carcinoma patients with synchronous distant metastasis

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Background: Data on the efficacy of including definitive local therapy to the primary head and neck disease (PHN) for non-nasopharyngeal head and neck squamous cell carcinoma (HNSCC) patients with synchronous distant metastasis are lacking. Methods: In this single institution retrospective study, we evaluated the outcomes of patients treated from 2000-2020 at UPMC for non-nasopharyngeal HNSCC with synchronous distant metastasis whose therapy included definitive therapy to the PHN. We evaluated overall survival (OS), calculated as date of diagnosis to date of death and progression free survival (PFS), calculated as date of diagnosis to date of death or progression. Based on an initial univariate analysis, the potential significant predictors were evaluated further in the multiple covariates Cox model via stepwise procedures. The relative mortality rates were summarized with hazard ratio (HR), with HR > 1.0 corresponding to increased mortality. Results: A total of 40 patients met inclusion criteria. The median age was 61, primary sites included 52.5% oropharynx (48% HPV +), 40% larynx/hypopharynx, 7.5% oral cavity, and 85% had a solitary metastatic lesion, most commonly in the lung. Definitive treatment of the PHN was with surgery (55%) or chemoradiation (45%), and 45% also underwent local treatment for all distant disease. The median PFS was 8.6 months (95% CI, 6.4-11.6), and OS was 14.2 months (95% CI, 10.9-27.5). In the 28% of patients that received induction therapy, there was a two-fold increase in median OS to 27.5 vs. 13.7 months, p = 0.06. In the 33% of patients that received anti-PD-1 mAb immunotherapy (IO), the median OS was significantly increased to 41.7 months (95% CI, 8.7-NR) vs. 12.1 months (95% CI, 8.4-14.4), p = 0.01, with a numeric increase in PFS as well (11.3 vs. 8.2 months respectively, p = 0.07). Notably no difference in PFS or OS was seen with type of local therapy to the PHN, receipt of local treatment to all distant disease, by HPV status, or year of diagnosis. In multivariate analysis including induction and other variables significant in univariate analysis (age, number of metastatic sites), IO was independently associated with improved OS (HR 3.123 (No IO vs. IO) (95% CI, 1.198-8.137), p = 0.02), as was age and number of metastatic sites. In the patients that received IO started as part of induction the median PFS and OS were 19.5 and 45.5 months respectively. Conclusions: We observed impressive survival in select non-nasopharyngeal HNSCC patients with synchronous distant metastasis treated with definitive local therapy to the primary head and neck disease in addition to induction and/or IO, with IO independently associated with improved OS. To our knowledge this is the first evaluation of the efficacy of definitive local therapy and IO in this population. Prospective evaluation is warranted.

Molecular alterations in Hürthle cell nodules and preoperative cancer risk

Hürthle cell carcinoma (HCC) is a distinct type of thyroid cancer genetically characterized by DNA copy number alterations (CNA), typically of genome haploidization type (GH-type). However, whether CNA also occurs in benign Hürthle cell adenomas (HCA) or Hürthle cell hyperplastic nodules (HCHN), and have diagnostic impact in fine-needle aspiration (FNA) samples, remains unknown. To address these questions, we (1) analyzed 26 HCC, 24 HCA, and 8 HCHN tissues for CNA and other mutations using ThyroSeq v3 (TSv3) next-generation sequencing panel, and (2) determined cancer rate in 111 FNA samples with CNA and known surgical outcome. We identified CNA, more often of the GH-type, in 81% of HCC and in 38% HCA, but not in HCHN. Among four HCC with distant metastasis, all had CNA and three TERT mutations. Overall, positive TSv3 results were obtained in 24 (92%) HCC, including all with ATA high risk of recurrence or metastasis. Among 111 FNA cases with CNA, 38 (34%) were malignant and 73 (66%) benign. A significant correlation between cancer rate and nodule size was observed, particularly among cases with GH-type CNA, where every additional centimeter of nodule size increased the malignancy odds by 1.9 (95% CI 1.3-2.7; P = 0.001). In summary, the results of this study demonstrate that CNA characteristic of HCC also occur in HCA, although with lower frequency, and probability of cancer in nodules with CNA increases with nodule size. Detection of CNA, in conjunction with other mutations and nodule size, is helpful in predicting malignancy in thyroid nodules.

Impact of molecular testing on detecting mimics of oncocytic neoplasms in thyroid fine-needle aspirates diagnosed as follicular neoplasm of Hürthle cell (oncocytic) type

BACKGROUND

Some thyroid nodules cytologically presenting as follicular neoplasm, Hürthle cell (Oncocytic) type (FNHCT), are not oncocytic tumors and represent autonomously functioning thyroid nodules (AFTNs) with TSHR, GNAS, and EZH1 mutations or oncocytic metaplasia. A to be defined subset of FNHCT harbors genome haploidisation-type DNA copy number alterations (GH-CNA). Molecular profiling of FNHCT may distinguish oncocytic neoplasms from its mimics.

METHODS

Consecutive fine-needle aspirates of 180 thyroid nodules over 37 months diagnosed as FNHCT and tested by ThyroSeq v3 were identified. Histologic follow-up was available for 79 of 180 nodules (44%).

RESULTS

No molecular alterations were found in 76 of 180 nodules (42%), of which 15 were resected (oncocytic metaplasia, n = 7; follicular oncocytic adenoma, n = 8). Of nodules followed without surgery, 17 of 101 (17%) showed TSHR, EZH1, and GNAS mutations of AFTNs. Papillary thyroid carcinoma was identified by BRAF V600E (n = 2) and hyalinizing trabecular adenoma by PAX8-GLIS3 (n = 1). GH-CNA alone was detected in 42 of 180 FNHCT nodules (23%), of which 29 were resected and histologically diagnosed as follicular oncocytic neoplasms. All remaining resected nodules were histologically proven oncocytic neoplasms: 1) RAS-like alterations without GH-CNA (n = 25) and 2) TERT and/or TP53 mutations co-occurring with GH-CNA (n = 6), including anaplastic thyroid carcinoma arising from follicular oncocytic carcinoma with TP53, TERT mutations with GH-CNA (n = 2).

CONCLUSIONS

A proportion of FNHCT nodules are AFTNs and oncocytic metaplasias, which can be suspected based on characteristic mutations or lack of alterations on molecular testing. Among resected FNHCTs, GH-CNAs characterize approximately half of histologically confirmed follicular oncocytic neoplasms.

RB1, p16, and Human Papillomavirus in Oropharyngeal Squamous Cell Carcinoma

While P16 immunohistochemistry (IHC) is a well-established surrogate marker of Human Papillomavirus (HPV) in oropharyngeal squamous cell carcinoma (OSCC), Retinoblastoma 1 (RB1) loss may lead to p16 overexpression in the absence of HPV. We determined the proportion of p16-positive/HPV-negative OSCC with RB1 loss and other alterations in RB1/p16 pathway, and tested RB1 IHC as a prognostic biomarker for OSCC, along with the 8th edition of AJCC staging manual. P16 and RB1 IHC and HPV DNA in situ hybridization (ISH) were performed on 257 OSCC. High risk HPV RNA ISH, RB1 fluorescence in situ hybridization (FISH), and next generation sequencing (NGS) were done on p16-positive/HPV DNA ISH-negative OSCC. Disease free survival (DFS) was used as an endpoint. In the entire cohort and in p16-positive (n = 184) and p16-negative (n = 73) subgroups, AJCC 8th edition staging correlated with DFS (p < 0.01). RB1 IHC showed RB1 loss in p16-positive OSCC only (79/184, 43%). RB1 loss by IHC is associated with a better DFS, without providing additional prognostic information for patients with p16-positive OSCC. HPV RNA ISH was positive in 12 of 14 HPV DNA ISH-negative cases. RB1 IHC showed loss in 10 of 15 HPV DNA ISH-negative cases and in 1 of 2 HPV RNA ISH-negative cases. Overall, only one case of p16-positive/HPV RNA ISH-negative OSCC showed RB1 loss by IHC (1/184, 0.5%). Of the 10 p16-positive and HPV DNA ISH-negative cases with RB1 loss by IHC, 2 had RB1 hemizygous deletion and 3 showed Chromosome 13 monosomy by FISH. No RB1 mutations were detected by NGS. Other molecular alterations in p16-positive/HPV DNA ISH-negative cases included TP53 and TERT mutations and DDX3X loss. HPV-independent RB1 inactivation rarely results in false positive p16 IHC. RB1 inactivation by high risk HPV E7 oncoprotein may co-exist with RB1 deletion. RB1 loss is a favorable prognosticator and occurs exclusively in p16-positive OSCC. The 8th edition of the AJCC staging manual satisfactorily predicts DFS of OSCC patients.

Primary and Secondary/ Metastatic Salivary Duct Carcinoma Presenting within the Sinonasal Tract

Traditionally, sinonasal adenocarcinomas have been subdivided into intestinal (ITAC) and non-intestinal (non-ITAC) categories. The latter encompasses salivary-type adenocarcinomas originating from the seromucinous glands of the sinonasal mucosa and non-salivary adenocarcinomas. The non-salivary adenocarcinoma category is further subdivided into low-and high-grade variants. Among salivary-type sinonasal adenocarcinomas, tumors recapitulating salivary duct carcinoma (SDC) are exceedingly rare, but some might have been lumped into the high-grade non-ITAC category. To date, only three primary SDCs originating in the sinonasal tract have been reported. We herein describe 7 cases of SDC including one previously reported case (4 primary sinonasal, 3 metastatic/ extension from parotid gland SDC). The primary tumors affected 3 males and one female aged 60 - 75. Different sites were involved by the primary tumors while the secondary tumors affected the sphenoidal (2) and the frontal + maxillary (1) sinuses. Three primary tumors were de novo high-grade SDC and one was confined to contours of a pre-existing pleomorphic adenoma. All 3 secondary tumors were SDC ex pleomorphic adenoma of the parotid with a long history of recurrences, ultimately involving the sinonasal tract. Androgen receptor was positive in 7/7 cases. Four of 6 cases were strongly HER2/neu + (either score 3 + or with verified amplification). This small case series adds to the delineation of primary sinonasal SDC highlighting that almost half of invasive SDC presenting within sinonasal tract indeed represents extension or metastasis from a parotid gland primary. There is a tendency towards overrepresentation of HER2/neu-positive cases in both categories (primary and metastatic), but this needs clarification in larger studies.

Evaluation of NR4A3 immunohistochemistry (IHC) and fluorescence in situ hybridization and comparison with DOG1 IHC for FNA diagnosis of acinic cell carcinoma

BACKGROUND

Acinic cell carcinoma (AcCC) is diagnostically challenging on fine-needle aspiration because it can mimic several other neoplasms or even normal acinar tissue. Immunopositivity for DOG1, especially circumferential membranous staining, can support the diagnosis of AcCC but is not entirely specific, and it is prone to technical and interpretive challenges on small specimens. NR4A3 (nuclear receptor subfamily 4 group A member 3) translocation and nuclear NR4A3 overexpression were recently described in the majority of AcCCs. Here, the authors evaluate the performance of NR4A3 immunohistochemistry (IHC) and NR4A3 break-apart fluorescence in situ hybridization (FISH) on cell block preparations and compare them with DOG1 IHC in distinguishing AcCC from other entities in the differential diagnosis.

METHODS

The authors identified 34 cytology cell blocks with lesional cells, including 11 specimens of AcCC (2 of which derived from 1 patient and showed high-grade transformation) as well as 2 secretory carcinomas, 7 salivary duct carcinomas, 4 mucoepidermoid carcinomas, 3 oncocytomas, 3 renal cell carcinomas, and 6 specimens containing nonneoplastic salivary gland tissue. NR4A3 IHC, DOG1 IHC, and NR4A3 FISH were attempted for all cases.

RESULTS

NR4A3 IHC had 81.8% sensitivity and 100% specificity for AcCC, whereas NR4A3 FISH had 36.4% sensitivity and 100% specificity, although 4 cases (3 mucoepidermoid carcinomas and 1 salivary gland tissue sample) could not be analyzed because of low cellularity. Notably, no normal acinar tissue specimens showed NR4A3 positivity by IHC or FISH. In addition, DOG1 IHC had 72.7% sensitivity and 92% specificity.

CONCLUSIONS

NR4A3 IHC is highly specific for the diagnosis of AcCC and is more sensitive than DOG1 IHC and NR4A3 FISH. In addition, NR4A3 IHC performance is not improved by the inclusion of DOG1 IHC. Finally, NR4A3 positivity resolves the perennial problem of distinguishing AcCC from normal acinar tissue.

The effect of locality of residence (LOR) and socioeconomic status (SES) on mortality in patients with squamous cell carcinoma of the head and neck (HNSCC): 20-year experience at the UPMC Hillman Cancer Center

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Background: As cancer centers expand, evaluation of potential disparities in outcomes amongst the catchment area is critically important. We examined the effect of LOR and SES on overall survival (OS) in HNSCC patients treated at HCC, which spans 29 counties in western Pennsylvania with diverse socioeconomic profiles across urban and rural localities. Methods: Retrospective review included patients with primary HNSCC (excluding M1 and recurrent disease) treated at HCC 1997-2018. Using Rural-Urban Commuting Area codes, LOR was classified as urban/suburban or rural according to ZIP code. SES was defined by medium income level (low, moderate (Mod), middle (Mid), Upper) via Federal Financial Institutions Examination Council geocoded census tract data. Kaplan-Meier methods and Cox regression models were used to evaluate OS. Results: 3512 patients were identified. Median age was 61, 72.7% male, 93.2% White, 18% HPV +, 75.5% urban/suburban, and by SES: 4% Low, 21% Mod, 46% Mid, and 19% Upper. Primary site included 35.2% oral cavity, 28.4% oropharynx, 28.1% larynx, 8.3% other, stage was majority III/IVa (61%), 66% had surgery and 54% received multimodality treatment (tx). While median OS differed significantly by race (Black: 5.8 vs. White: 7.3 years, p = 0.0457) and SES (Low: 4.1 vs. Mod: 5.3 vs. Mid: 7.3 vs. Upper: 9.1 years, p < 0.0001), there was no difference by LOR (rural: 7.7 vs. urban/suburban: 7.2 years, p = 0.99). Multivariable Cox Regression showed lower SES was associated with a higher risk of death [(Low vs. Upper, HR: 1.416, 95% CI: 1.023-1.959) (Mod vs. Upper, HR:1.443, 95% CI: 1.214 – 1.716), p = 0.0004], adjusting for LOR and factors associated with OS in univariate analysis (age, smoking status, primary site, staging, tx, HPV status, race, and enrollment on clinical trial). The effect of LOR, race, and enrollment on clinical trial were not significant in multivariate analysis. Conclusions: SES was independently associated with OS in HNSCC patients treated at HCC, while LOR was not associated with OS. The lack of difference by LOR may be partially explained by HCC’s efforts to increase access to care throughout the catchment area by establishing community sites. However, a focus on improving outcomes for lower SES HNSCC patients is needed.

The impact of tumor hypoxia on the clinical efficacy of anti-PD-1 mAb treatment in recurrent/metastatic HNSCC patients (R/M)

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Background: Anti-PD-1 mAbs have changed the landscape of R/M HNSCC treatment, but physical, immunologic, and metabolic barriers present in the tumor microenvironment are likely drivers of low response rates. Hypoxia is a well-established feature of the tumor microenvironment and may act as a barrier to T cell infiltration and function. We evaluated the effect of hypoxia on the efficacy of anti-PD-1 mAb treatment in R/M HNSCC patients. Methods: We conducted a retrospective analysis of R/M patients treated with anti-PD-1 mAb that had consented to the UPMC Hillman tissue banking protocol (HCC 99-069). Pre-treatment archival FFPE samples were analyzed via immunofluorescent imaging for number of CD8+ T cells (CD8), Tregs, and the percent area (% CAIX) and mean intensity (Int) of carbonic anhydrase IX, a well-described marker of hypoxia. Tissue sections stained with PanCK, CAIX, CD8, Foxp3, and DAPI were imaged with an Olympus IX 83 microscope. ImageJ software and custom software plugins were used to determine %CAIX, Int, CD8, and Treg. PD-L1 by IHC was reported as a combined positive score (CPS) defining positive as CPS > 1. We compared non-responders (NR) i.e. PD to responders (R) i.e. PR or SD, and analyzed OS, PFS. All data were analyzed using GraphPad Prism software. Two-tailed unpaired t test was used when comparing 2 groups, 1-way ANOVA was used for multiple comparisons, and log-rank test was used for survival analysis. Results: The 36 patients included were 69% male, median age 59, 58% smokers. 61% were platinum failure. Primary site included 39% OC, 22% OPC (38% HPV positive), 17% Larynx, 17% other, 5% hypopharynx. Low %CAIX/Int, high CD8, and high CD8/Treg were all significantly associated with R. Patients with low %CAIX/Int (12 month OS Low: 75% vs. Mid: 17% vs. High:8%, p = 0.02) and high CD8/Treg had a significant increase in OS. Only high CD8 was associated with significantly higher PFS. Low %CAIX alone showed a non-significant trend towards increased R and no difference in PFS/OS. There was no difference in CD8, CD8/Treg, PD-L1 and Treg between %CAIX/Int groups. Conclusions: To our knowledge this is the first evaluation of tumor hypoxia as a predictive biomarker in anti-PD-1 mAb treated R/M HNSCC patients. Lower hypoxia by %CAIX/Int was associated with significantly increased response and OS. While further analysis in a larger dataset is needed to confirm, the lack of significant difference in CD8, Treg, PD-L1, and CD8/Treg between %CAIX/Int groups (Low, Mid, High) suggests that hypoxia may be an independent predictive marker.

Transition to a virtual multidisciplinary tumor board during the COVID-19 pandemic: University of Pittsburgh experience

Multidisciplinary conferences (MDC) are an important component of head and neck oncologic care including diagnosis, treatment, and survivorship. Virtual MDC allows for improved collaboration between providers at distant sites and proper allocation of health care resources in a time of crisis. When approached systematically, a virtual MDC is feasible to design and implement in a large academic medical center with multiple satellite hospitals.

Intraoperative Margin Assessment in Head and Neck Cancer: A Case of Misuse and Abuse?

Surgical removal with negative margins is the preferred management of oral squamous cell carcinomas. This review summarizes statements by professional organizations and data supporting the specimen-driven approach to margin assessment. Practical aspects of the intraoperative margin assessment, as guided by gross examination, are presented. The most cost- and time-efficient method of intraoperative margin assessment depends on desired margin clearance and likelihood of other adverse histologic factors, such as extranodal extension, perineural invasion, which are likelier in advanced carcinomas. Intraoperative surgeon-pathologist communication can be improved by reporting to surgical team gross distances to all or selected closest margins, before choosing margins for microscopic frozen examination. Case specific mitigation strategies to minimize the negative impact of tumor-bed driven margin assessment or of suboptimal margin revision are proposed. Based on size, shape, histology, size of carcinoma at the margin, and orientation of the additional tissue, margin revision may be judged as adequate (conversion of a positive margin into a negative one), inadequate (positive margin remains positive), or indeterminate. The significance of anatomic subsite based labeling, radial margin sampling from the main resection specimen, and the relationship between the distance to closest margin and local control are highlighted. The modern definition of safe margin would account for other parameters, such as perineural invasion. An updated approach to resolution of frozen versus permanent sampling issues is outlined. Future studies are needed to design and validate risk models that would help to determine for individual patient what represents a safe margin and how to judge the quality of margin revision.

The role of adjuvant (chemo-)radiotherapy in oral cancers in the contemporary era

Squamous cell carcinoma of oral cavity (OSCC) is predominantly managed with surgery. Post-operative radiotherapy (PORT) and chemoradiotherapy (POCRT) enhance disease control in OSCC patients with adverse anatomic and pathologic primary and nodal features. Knowledge about disease behavior, surgery and radiotherapy advances, and the emergence of new systemic agents prompt refinement of PORT volumes and POCRT regimens. Traditional and emerging prognostic models that include adverse histopathological features underpin such approaches. This review summarizes research over recent decades with emphasis on the 2015 to Feb 2019 period describing: (1) Indications for PORT and/or POCRT, addressing surgical "margin status" including the definition of a "clear" margin to permit withholding PORT/POCRT; these concepts include characterizing the specimen yielding these measurements, the optimal time point to assess these findings, and the putative value of a "revised margin" performed during the same operative procedure, (2) Emerging prognostic factors including nodal burden (total number of involved lymph nodes) and perineural invasion, (3) PORT volume design, dose/fractionation and optimal surgery-to-PORT interval, (4) Chemotherapy dose, schedule, and agents, and (5) On-going clinical trials involving systemic agents and combinations of chemotherapy with immunotherapy.

Performance of a Multigene Genomic Classifier in Thyroid Nodules With Indeterminate Cytology: A Prospective Blinded Multicenter Study

Question

Can the diagnosis of benign disease or cancer in thyroid nodules with indeterminate cytology be established by molecular testing instead of diagnostic surgery?

Findings

This prospective, blinded, multicenter cohort study of a multigene genomic classifier (ThyroSeq v3) test included 257 indeterminate cytology thyroid nodules with informative test results. It demonstrated a high sensitivity (94%) and reasonably high specificity (82%), with 61% of the nodules yielding a negative test result and only 3% residual cancer risk in these nodules.

Meanings

Up to 61% of patients with indeterminate cytology thyroid nodules may avoid diagnostic surgery by undergoing multigene genomic classifier testing.

Importance

Approximately 20% of fine-needle aspirations (FNA) of thyroid nodules have indeterminate cytology, most frequently Bethesda category III or IV. Diagnostic surgeries can be avoided for these patients if the nodules are reliably diagnosed as benign without surgery.

Objective

To determine the diagnostic accuracy of a multigene classifier (GC) test (ThyroSeq v3) for cytologically indeterminate thyroid nodules.

Design, Setting, and Participants

Prospective, blinded cohort study conducted at 10 medical centers, with 782 patients with 1013 nodules enrolled. Eligibility criteria were met in 256 patients with 286 nodules; central pathology review was performed on 274 nodules.

Interventions

A total of 286 FNA samples from thyroid nodules underwent molecular analysis using the multigene GC (ThyroSeq v3).

Main Outcomes and Measures

The primary outcome was diagnostic accuracy of the test for thyroid nodules with Bethesda III and IV cytology. The secondary outcome was prediction of cancer by specific genetic alterations in Bethesda III to V nodules.

Results

Of the 286 cytologically indeterminate nodules, 206 (72%) were benign, 69 (24%) malignant, and 11 (4%) noninvasive follicular thyroid neoplasms with papillary-like nuclei (NIFTP). A total of 257 (90%) nodules (154 Bethesda III, 93 Bethesda IV, and 10 Bethesda V) had informative GC analysis, with 61% classified as negative and 39% as positive. In Bethesda III and IV nodules combined, the test demonstrated a 94% (95% CI, 86%-98%) sensitivity and 82% (95% CI, 75%-87%) specificity. With a cancer/NIFTP prevalence of 28%, the negative predictive value (NPV) was 97% (95% CI, 93%-99%) and the positive predictive value (PPV) was 66% (95% CI, 56%-75%). The observed 3% false-negative rate was similar to that of benign cytology, and the missed cancers were all low-risk tumors. Among nodules testing positive, specific groups of genetic alterations had cancer probabilities varying from 59% to 100%.

Conclusions and Relevance

In this prospective, blinded, multicenter study, the multigene GC test demonstrated a high sensitivity/NPV and reasonably high specificity/PPV, which may obviate diagnostic surgery in up to 61% of patients with Bethesda III to IV indeterminate nodules, and up to 82% of all benign nodules with indeterminate cytology. Information on specific genetic alterations obtained from FNA may help inform individualized treatment of patients with a positive test result.

Characterization of thyroid cancer driven by known and novel ALK fusions

ALK fusions are found in various tumors, including thyroid cancer, and serve as a diagnostic marker and therapeutic target. Spectrum and outcomes of ALK fusions found in thyroid nodules and cancer are not fully characterized. We report a series of 44 ALK-translocated thyroid neoplasms, including 31 identified preoperatively in thyroid fine-needle aspirates (FNA). The average patients' age was 43 years (range, 8-76 years); only one with radiation history. All 19 resected thyroid nodules with ALK fusion identified preoperatively were malignant. Among nodules with known surgical pathology (n = 32), 84% were papillary thyroid carcinomas (PTCs) and 16% poorly differentiated thyroid carcinomas (PDTCs). PTCs showed infiltrative growth with follicular architecture seen exclusively (30%) or in combination with papillary and/or solid growth (37%). Tumor multifocality was seen in 10 (31%) PTC cases. Most PDTC had a well-differentiated PTC component. Lymph node metastases were identified in 10/18 (56%) patients with neck dissection. The most common ALK fusion partners were STRN (n = 22) and EML4 (n = 17). In five cases, novel ALK fusion partners were discovered. All five PDTCs carried STRN-ALK fusion. On follow-up, ten patients were free of disease at 2-108 months, whereas two patients with PDTC died of disease. In summary, ALK fusion-positive thyroid carcinomas are typically infiltrative PTC with common follicular growth, which may show tumor dedifferentiation associated with increased mortality. Compared to EML4-ALK, STRN-ALK may be more common in PDTC, and ~10% of ALK fusions occur to rare gene partners. When ALK fusion is detected preoperatively in FNA samples, malignancy should be expected.

Early squamous cell carcinoma of the oral tongue with histologically benign lymph nodes: A model predicting local control and vetting of the eighth edition of the American Joint Committee on Cancer pathologic T stage

BACKGROUND

The eighth edition of the American Joint Committee on Cancer staging manual (AJCC8) added depth of invasion to the definition of pathologic T stage (pT). In the current study, the authors assess pT stage migration and the prognostic performance of the updated pT stage and compare it with other clinicopathologic variables in patients with early squamous cell carcinoma of the oral tongue (OTSCC; tumors measuring ≤4 cm) with histologically benign lymph nodes (pN0).

METHODS

A multi-institutional cohort of patients with early OTSCC was restaged as per AJCC8. Primary endpoints were local recurrence (LR) and locoregional recurrence (LRR). Influential variables were identified and an LR/LRR prediction model was developed.

RESULTS

There were a total of 494 patients, with 49 LR and 73 LRR. AJCC8 pT criteria resulted in upstaging of 37.9% of patients (187 of 494 patients), including 34.5% (64 of 185 patients) from pT2 to pT3, without improving the prognostication for LR or LRR. Both LR and LRR were found to be similar for patients with AJCC8 pT2 and pT3 disease. On multivariate analysis, LR was only found to be associated with distance to the closest margin (hazard ratio, 0.36; 95% CI, 0.20-0.64 [P = .0007]) and perineural invasion (hazard ratio, 1.92; 95% CI, 1.10-0.64 [P = .046]). Based on these 2 predictors, a final proportional hazards regression model (which may be used similar to a nomogram) was developed. The proposed model appeared to be superior to AJCC pT stage for estimating the probability of LR and LRR for individual patients with early OTSCC.

CONCLUSIONS

AJCC8 pT criteria resulted in pT upstaging of patients with pN0 disease without improved LR or LRR prognostication. The proposed model based on distance to the closest margin and perineural invasion, status outperformed pT as a predictor of LR and LRR in patients with early OTSCC.

Hamartoma of the Oral Cavity with Ectopic Meningothelial Elements in Infants: A Rare Entity with Report of Two Cases

Choristomas and hamartomas within the oral cavity are relatively uncommon lesions and may present with diverse clinical and histopathological appearances. In this report, we describe two infant patients with hamartoma with ectopic meningothelial elements involving tongue and maxillary alveolar ridge. To the best of our knowledge, these are the first two cases in which a meningothelial proliferation has been identified in the oral cavity. Hamartoma with ectopic meningothelial elements is a rare condition that has been classically described occurring in the scalp. These lesions are characterized by bland round to spindle-shape cells that interdigitate through collagen bundles and express progesterone receptor and epithelial membrane antigen by immunohistochemistry supporting a meningothelial origin.

GLIS Rearrangement is a Genomic Hallmark of Hyalinizing Trabecular Tumor of the Thyroid Gland

BACKGROUND

Hyalinizing trabecular tumor (HTT) is a rare thyroid neoplasm with a characteristic trabecular growth pattern and hyalinization. This lesion has been the subject of long-term controversy surrounding its genetic mechanisms, relationship to papillary thyroid carcinoma (PTC), and malignant potential. Due to the presence of nuclear features shared with PTC, HTT frequently contributes to a false-positive cytology, which hampers patient management. The goal of this study was to apply genome-wide sequencing analyses to elucidate the genetic mechanisms of HTT and its relationship to PTC.

METHODS

Whole-exome, RNA-Seq, and targeted next-generation sequencing analyses were performed to discover and characterize driver mutations in HTT. RNA-Seq results were used for pathway analysis. Tissue expression of GLIS3 and other proteins was detected by immunohistochemistry. The prevalence of GLIS fusions was studied in 17 tumors initially diagnosed as HTT, 220 PTC, and 10,165 thyroid fine-needle aspiration samples.

RESULTS

Using whole-exome and RNA-Seq analyses of the initial three HTT, no known thyroid tumor mutations were identified, while in-frame gene fusion between PAX8 exon 2 and GLIS3 exon 3 was detected in all tumors. Further analysis identified PAX8-GLIS3 in 13/14 (93%) and PAX8-GLIS1 in 1/14 (7%) of HTT confirmed after blind pathology review. The fusions were validated by Sanger sequencing and FISH. The fusions resulted in overexpression of the 3'-portion of GLIS3 and GLIS1 mRNA containing intact DNA-binding domains of these transcription factors and upregulation of extracellular matrix genes including collagen IV. Immunohistochemistry confirmed upregulation and deposition of collagen IV and pan-collagen in HTT. The analysis of 220 PTC revealed no PAX8-GLIS3 and one PAX8-GLIS1 fusion. PAX8-GLIS3 was prospectively identified in 8/10,165 (0.1%) indeterminate cytology fine-needle aspiration samples; 5/5 resected fusion-positive nodules were HTT on surgical pathology.

CONCLUSIONS

This study demonstrates that GLIS rearrangements, particularly PAX8-GLIS3, are highly prevalent in HTT but not in PTC. The fusions lead to overexpression of GLIS, upregulation of extracellular matrix genes, and deposition of collagens, which is a characteristic histopathologic feature of HTT. Due to unique genetic mechanisms and an indolent behavior, it is proposed to rename this tumor as "GLIS-rearranged hyalinizing trabecular adenoma."

Use of nonsteroidal anti-inflammatory drugs predicts improved patient survival for PIK3CA-altered head and neck cancer

Head and neck cancer patients taking NSAIDs with PIK3CA tumor alterations demonstrate improved survival. Studies in relevant preclinical models implicate signaling via COX2-mediated production of PGE₂ as an underlying mechanism for this survival benefit.

PIK3CA is the most commonly altered oncogene in head and neck squamous cell carcinoma (HNSCC). We evaluated the impact of nonsteroidal anti-inflammatory drugs (NSAIDs) on survival in a PIK3CA-characterized cohort of 266 HNSCC patients and explored the mechanism in relevant preclinical models including patient-derived xenografts. Among subjects with PIK3CA mutations or amplification, regular NSAID use (≥6 mo) conferred markedly prolonged disease-specific survival (DSS; hazard ratio 0.23, P = 0.0032, 95% CI 0.09–0.62) and overall survival (OS; hazard ratio 0.31, P = 0.0043, 95% CI 0.14–0.69) compared with nonregular NSAID users. For PIK3CA-altered HNSCC, predicted 5-yr DSS was 72% for NSAID users and 25% for nonusers; predicted 5-yr OS was 78% for regular NSAID users and 45% for nonregular users. PIK3CA mutation predicted sensitivity to NSAIDs in preclinical models in association with increased systemic PGE₂ production. These findings uncover a biologically plausible rationale to implement NSAID therapy in PIK3CA-altered HNSCC.

Analysis of oncogenic activities of protein kinase D1 in head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is the sixth leading cause of cancer death in the US. The protein kinase D (PKD) family has emerged as a promising target for cancer therapy with PKD1 being most intensively studied; however, its role in HNSCC has not been investigated.

METHODS

The expression of PKD was evaluated in human HNSCC by quantitative RT-PCR, Western blot and immunohistochemistry. Cell proliferation, wound healing, and matrigel invasion assays were performed upon siRNA-mediated knockdown of PKD1 in HNSCC cells, and subcutaneous xenograft mouse model was established by implantation of the stable doxycycline (Dox)-inducible PKD1 expression cell lines for analysis of tumorigenic activity in vivo.

RESULTS

PKD1 was frequently downregulated in HNSCC cell lines at both transcript and protein levels. In human HNSCC tissues, PKD1 was significantly down-regulated in localized tumors and metastases, and in patient-paired tumor tissues as compared to their normal counterparts, which was in part due to epigenetic modification of the PRKD1 gene. The function of PKD1 in HNSCC was analyzed using stable doxycycline-inducible cell lines that express native or constitutive-active PKD1. Upon induction, the rate of proliferation, survival, migration and invasion of HNSCC cells did not differ significantly between the control and PKD1 overexpressing cells in the basal state, and depletion of endogenous PKD1 did not impact the proliferation of HNSCC cells. However, the median growth rate of the subcutaneous HNSCC tumor xenografts over time was elevated with PKD1 induction, and the final tumor weight was significantly increased in Dox-induced vs. the non-induced tumors. Moreover, induced expression of PKD1 promoted bombesin-induced cell proliferation of HNSCC and resulted in sustained ERK1/2 activation in response to gastrin-releasing peptide or bombesin stimulation, suggesting that PKD1 potentiates GRP/bombesin-induced mitogenic response through the activation of ERK1/2 in HSNCC cells.

CONCLUSIONS

Our study has identified PKD1 as a frequently downregulated gene in HNSCC, and functionally, under certain cellular context, may play a role in GRP/bombesin-induced oncogenesis in HNSCC.

Measuring Depth of Invasion in Early Squamous Cell Carcinoma of the Oral Tongue: Positive Deep Margin, Extratumoral Perineural Invasion, and Other Challenges

The 8th edition of American Joint Committee on Cancer (AJCC 8th) staging manual incorporated depth of invasion (DOI) into pT stage of oral cavity cancer. The aim of this study was to characterize several histological findings that may complicate measurement of DOI in early conventional squamous cell carcinomas (SCC) of the oral tongue: (1) lack of or minimal residual carcinoma following biopsy; (2) positive deep margin; (3) extratumoral perineural invasion (PNI); and (4) lymphatic or vascular invasion. Conventional SCC of the oral tongue (n = 407) with the largest dimension of ≤ 4 cm and with a negative elective cervical lymph node dissection (pN0) were reviewed. A clear plastic ruler was used to measure DOI by dropping a "plumb line" to the deepest point of the invasive tumor from the level of the basement membrane of the normal mucosa closest to the invasive tumor. Examples of identifying  reference point on the mucosal surface of oral tongue from which to measure the DOI are illustrated. In the experience of one contributing institution, the residual carcinoma was absent in 14.2% of glossectomies (34/239), while in 4.8% of cases (10/205) there was only minimal residual carcinoma. In 11.5% (21/183) of pT2 cases the deep margin was positive and thus DOI and pT may be underestimated. Of all cases with PNI, extratumoral PNI was identified in 23.1% (31/134) of cases, but represented the deepest point of invasion in only two cases. In one case, lymphatic invasion represented the deepest point of invasion and could have led to upstaging from pT1 to pT2. In conclusion, DOI measurement for SCC of the oral tongue may require re-examination of the diagnostic biopsy in up to 20% of cases due to the absence or only minimal residual carcinoma in glossectomy specimens. In 11.5% of apparently pT2 cases, DOI may be underestimated due to the positive deep margin. Rarely, extratumoral PNI or lymphatic invasion may be the deepest point of invasion. Overall, two issues (absent or minimal residual disease and positive deep margin) may confound DOI measurement in early SCCs of oral tongue.

Improving margin revision: Characterization of tumor bed margins in early oral tongue cancer

OBJECTIVES

To improve margin revision, this study characterizes the number, fragmentation, and orientation of tumor bed margins (TBM) in patients with pT1-2 pN0 squamous cell carcinoma (SCC) of the oral tongue.

MATERIALS AND METHODS

Pathology reports (n=346) were reviewed. TBM parameters were indexed. In Group 1 patients all margins were obtained from the glossectomy specimen and there were no TBM. In Revision Group/Group 2 (n=103), tumor bed was sampled to revise suboptimal margins identified by examination of the glossectomy specimen. In Group 3 (n=124), TBM were obtained before examination of the glossectomy specimen.

RESULTS AND CONCLUSIONS

Fewer TBMs were obtained per patient in Group 2 compared to Group 3 (57/103, 55% of patients with <3 vs. 117/124, 94%, ≥3 TBMs, respectively). The new margin surface was more frequently indicated in Group 2 compared to Group 3 (59/103, 57%, vs. 19/124, 15%, p<.001). If glossectomy specimen margins are accepted as the reference standard, then the TBM was 15% sensitive in Group 2 (95% confidence interval [CI], 7-29) and 32% sensitive in Group 3 (95% CI, 15-55). TBM fragmentation (23/103, 22% vs. 42/124, 34%) and frozen vs. permanent discrepancies (8/103, 3% vs. 3/124, 2%) were similar between Groups 2 and 3. The new margin surface was not indicated in 6 of 11 cases with discrepant frozen vs. permanent pathology findings, precluding judgment on final margin status. To facilitate the assessment of final margins, TBM should be represented by one tissue fragment with a marked new margin surface.

HMGA2 is a specific immunohistochemical marker for pleomorphic adenoma and carcinoma ex-pleomorphic adenoma

AIMS

Accurate classification of salivary gland neoplasms may be challenging, owing to morphological overlap, particularly in small biopsies. Recurrent translocations involving the high-mobility group AT-hook 2 (HMGA2) gene are present in a subset of pleomorphic adenomas (PAs) and carcinoma ex-pleomorphic adenomas (CA ex-PAs). The aim of this study was to evaluate immunohistochemical HMGA2 expression in 225 salivary gland tumours, including 56 PAs, 37 CA ex-PAs, and 132 potential histological mimics, to determine its diagnostic utility.

METHODS AND RESULTS

HMGA2 expression was identified in 19 PAs (33.9%) and nine CA ex-PAs (24.3%). Expression was strong and diffuse throughout all PAs, and in four of nine positive CA ex-PAs. In five CA ex-PAs, HMGA2 showed weak-to-strong multifocal staining within the carcinomatous component, and strong diffuse HMGA2 expression in the residual PA. Among histological mimics, six de-novo salivary duct carcinomas (28.5%), three epithelial-myoepithelial carcinomas (33.3%) and one case each of myoepithelioma and basal cell adenoma expressed HMGA2. Fluorescence in-situ hybridization for HMGA2 rearrangement performed on a subset of tumours that showed diffuse HMGA2 expression in PAs and CA ex-PAs was frequently associated with rearrangement of the HMGA2 locus, whereas cases of de-novo salivary duct carcinoma, or CA ex-PA with limited or no HMGA2 expression, had an intact HMGA2 locus.

CONCLUSIONS

HMGA2 expression is a highly specific (96.2%), but low-sensitivity (29.8%), marker for PA and CA ex-PA when compared with histological mimics, and is frequently associated with rearrangement of the HMGA2 locus.

Frequent IDH2 R172 mutations in undifferentiated and poorly-differentiated sinonasal carcinomas

Sinonasal undifferentiated carcinoma (SNUC) is a high-grade malignancy with limited treatment options and poor outcome. A morphological spectrum of 47 sinonasal tumours including 17 (36.2%) SNUCs was analysed at genomic level. Thirty carcinomas (cohort 1) were subjected to a hybridization exon-capture next-generation sequencing assay (MSK-IMPACT^TM ) to interrogate somatic variants in 279 or 410 cancer-related genes. Seventeen sinonasal tumours (cohort 2) were examined only for the presence of IDH1/2 exon 4 mutations by Sanger sequencing. IDH2 R172 single nucleotide variants were overall detected in 14 (82.4%) SNUCs, in two (20%) poorly-differentiated carcinomas with glandular/acinar differentiation, and in one of two high-grade neuroendocrine carcinomas, large cell type (HGNECs). No IDH2 mutation was detected in any of five olfactory neuroblastomas or in any of five SMARCB1-deficient carcinomas. Among 12 IDH2-mutated cases in cohort 1, five (41.7%) harboured co-existing TP53 mutations, four (33.3%) CDKN2A/2B loss-of-function alterations, four (33.3%) MYC amplification, and three (25%) had concurrent SETD2 mutations. AKT1 E17K and KIT D816V hotspot variants were each detected in one IDH2-mutated SNUC. The vast majority of SNUCs and variable proportions of other poorly-differentiated sinonasal carcinomas may be amenable to IDH2-targeted therapy. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Solid Lymph Nodes as an Imaging Biomarker for Risk Stratification in Human Papillomavirus-Related Oropharyngeal Squamous Cell Carcinoma

BACKGROUND AND PURPOSE

Human papillomavirus-related oropharyngeal squamous cell carcinoma is associated with cystic lymph nodes on CT and has a favorable prognosis. A subset of patients with aggressive disease experience treatment failure. Our aim was to determine whether the extent of cystic lymph node burden on staging CT can serve as an imaging biomarker to predict treatment failure in human papillomavirus-related oropharyngeal squamous cell carcinoma.

MATERIALS AND METHODS

We identified patients with human papilloma virus-related oropharyngeal squamous cell carcinoma and staging neck CTs. Demographic and clinical variables were recorded. We retrospectively classified the metastatic lymph node burden on CT as cystic or solid and assessed radiologic extracapsular spread. Biopsy, subsequent imaging, or clinical follow-up was the reference standard for treatment failure. The primary end point was disease-free survival. Cox proportional hazard regression analyses of clinical, demographic, and anatomic variables for treatment failure were performed.

RESULTS

One hundred eighty-three patients were included with a mean follow-up of 38 months. In univariate analysis, the following variables had a statistically significant association with treatment failure: solid-versus-cystic lymph nodes, clinical T-stage, clinical N-stage, and radiologic evidence of extracapsular spread. The multivariate Cox proportional hazard model resulted in a model that included solid-versus-cystic lymph nodes, T-stage, and radiologic evidence of extracapsular spread as independent predictors of treatment failure. Patients with cystic nodal metastasis at staging had significantly better disease-free survival than patients with solid lymph nodes.

CONCLUSIONS

In human papilloma virus-related oropharyngeal squamous cell carcinoma, patients with solid lymph node metastases are at higher risk for treatment failure with worse disease-free survival. Solid lymph nodes may serve as an imaging biomarker to tailor individual treatment regimens.

Retracted: Worst Pattern Of Invasion and occult cervical metastases for oral squamous carcinoma

The above article, published online in Wiley Online Library as the Version of Record on March 28, 2017 (doi 10.1002/hed.24754), has been retracted by agreement between the Editor-in-Chief, Ehab Y. Hanna, and Wiley Periodicals, Inc. The retraction has been agreed owing to a dispute as to authorship and inclusion of some data in the analysis.

REFERENCE

Velosa, C., Shi, Q., Stevens, T. M., Chiosea, S. I., Purgina, B., Carroll, W., Rosenthal, E., Morlandt, A., Loree, T. and Brandwein-Weber, M. S. (2017), Worst pattern of invasion and occult cervical metastases for oral squamous carcinoma. Head Neck. doi:10.1002/hed.24754.

Salivary Duct Carcinoma: An Update on Morphologic Mimics and Diagnostic Use of Androgen Receptor Immunohistochemistry

More than 15 years ago, seminal studies by Dr. E. Leon Barnes and colleagues transformed our understanding of salivary duct carcinoma (SDC) and, in doing so, paved the way for contemporary diagnostic and therapeutic approaches to this aggressive salivary adenocarcinoma. In particular, attention to the apocrine phenotype of SDC and expression of androgen receptor (AR) by immunohistochemistry has improved the diagnostic accuracy and showed how SDC can be reliably distinguished from its morphologic mimics (i.e., other salivary gland carcinomas with high grade transformation, low grade cribriform cystadenocarcinoma, and squamous cell carcinomas involving parotid). Furthermore, the observation that SDC shares AR expression with prostate cancer and apocrine breast cancer foresaw the discovery of common molecular alterations between SDC and these tumor types and draw attention to androgen deprivation therapy for SDC patients.

Exome and genome sequencing of nasopharynx cancer identifies NF-κB pathway activating mutations

Nasopharyngeal carcinoma (NPC) is an aggressive head and neck cancer characterized by Epstein-Barr virus (EBV) infection and dense lymphocyte infiltration. The scarcity of NPC genomic data hinders the understanding of NPC biology, disease progression and rational therapy design. Here we performed whole-exome sequencing (WES) on 111 micro-dissected EBV-positive NPCs, with 15 cases subjected to further whole-genome sequencing (WGS), to determine its mutational landscape. We identified enrichment for genomic aberrations of multiple negative regulators of the NF-κB pathway, including CYLD, TRAF3, NFKBIA and NLRC5, in a total of 41% of cases. Functional analysis confirmed inactivating CYLD mutations as drivers for NPC cell growth. The EBV oncoprotein latent membrane protein 1 (LMP1) functions to constitutively activate NF-κB signalling, and we observed mutual exclusivity among tumours with somatic NF-κB pathway aberrations and LMP1-overexpression, suggesting that NF-κB activation is selected for by both somatic and viral events during NPC pathogenesis.

Nasopharyngeal cancer is frequently characterized by Epstein-Barr virus infection. Here, using genomic analyses, the authors find that the tumours harbour mutations in genes involved in the NF-κB signalling pathway or overexpress a viral oncoprotein, latent membrane protein 1.

Programmed Death-Ligand 1 Expression, Microsatellite Instability, Epstein-Barr Virus, and Human Papillomavirus in Nasopharyngeal Carcinomas of Patients from the Philippines

Most nasopharyngeal carcinomas (NPCs) in a high-incidence population are driven by Epstein-Barr virus (EBV) infection. EBV-associated malignancies have increased expression of the programmed death-ligand 1 (PD-L1). Immunotherapy agents targeting the PD-1/PD-L1 pathway have achieved durable treatment effects in patients with various cancer types including EBV-associated malignancies. In this study, we sought to investigate PD-L1 expression in a cohort of patients with NPCs from the Philippines. Fifty-six NPCs were studied for PD-L1, p16, and DNA mismatch repair (MMR) deficiency by immunohistochemistry. One case with MMR deficiency was also assessed for microsatellite instability (MSI) by polymerase chain reaction. EBV and human papillomavirus (HPV) status were tested by in situ hybridization. All NPCs were p16 negative. Three of the 56 NPCs (5%) were EBV negative (EBV-) and HPV negative, while one NPC (1/56, 2%) was EBV positive and showed MSI (EBV+/MSI). Positive PD-L1 expression (PD-L1+), defined as membranous staining in ≥1% tumor cells, was seen in 64% (36/56) of NPCs. All three EBV- NPCs were PD-L1+ as was the EBV+/MSI NPC. PD-L1+ was seen significantly more often in NPCs from non-smokers than those from smokers (23/28, 82% vs 9/18, 50%; P = 0.047). PD-L1+ was not associated with pT, pN, distant metastasis, or clinical stage (P > 0.05). PD-L1+ was not associated with overall survival (P = 0.473). In summary, our results show frequent PD-L1 expression in NPCs regardless of EBV status and a preferential PD-L1 expression in non-smokers. MSI and HPV positivity are exceedingly rare in NPCs.

Subsets of salivary duct carcinoma defined by morphologic evidence of pleomorphic adenoma, PLAG1 or HMGA2 rearrangements, and common genetic alterations

BACKGROUND

The authors hypothesized that histogenetic classification of salivary duct carcinoma (SDC) could account for de novo tumors and those with morphologic or molecular evidence (pleomorphic adenoma gene 1 [PLAG1], high-mobility group AT hook 2 [HMGA2] rearrangement, amplification) of pleomorphic adenoma (PA).

METHODS

SDCs (n = 66) were reviewed for morphologic evidence of PA. PLAG1 and HMGA2 alterations were detected by fluorescence in situ hybridization (FISH). PLAG1-positive tumors were tested by FISH for fibroblast growth factor receptor 1 (FGFR1) rearrangement. Thirty-nine tumors were analyzed using a commercial panel for mutations and copy number variations in 50 cancer-related genes.

RESULTS

On the basis of combined morphologic and molecular evidence of PA, 4 subsets of SDC emerged: 1) carcinomas with morphologic evidence of PA but intact PLAG1 and HMGA2 (n = 22); 2) carcinomas with PLAG1 alteration (n = 18) or 3) HMGA2 alteration (n = 12); and 4) de novo carcinomas, without morphologic or molecular evidence of PA (n = 14). The median disease-free survival was 37 months (95% confidence interval, 28.4-45.6 months). Disease-free survival and other clinicopathologic parameters did not differ for the subsets defined above. Combined Harvey rat sarcoma viral oncogene homolog/phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit α (HRAS/PIK3CA) mutations were observed predominantly in de novo carcinomas (5 of 8 vs 2 of 31 tumors; P = .035). Erb-B2 receptor tyrosine kinase 2 (ERBB2) copy number gain was not observed in de novo carcinomas (0 of 8 vs 12 of 31 tumors; P = .08). Tumor protein 53 (TP53) mutations were more common in SDC ex pleomorphic adenomas than in de novo carcinomas (17 of 31 vs 1 of 8 tumors; P = .033).

CONCLUSIONS

The genetic profile of SDC varies with the absence or presence of pre-existing PA and its cytogenetic signature. Most de novo SDCs harbor combined HRAS/PIK3CA mutations and no ERBB2 amplification. Cancer 2016;122:3136-44. © 2016 American Cancer Society.

Phase II randomized trial of radiation therapy, cetuximab, and pemetrexed with or without bevacizumab in patients with locally advanced head and neck cancer

BACKGROUND

We previously reported the safety of concurrent cetuximab, an antibody against epidermal growth factor receptor (EGFR), pemetrexed, and radiation therapy (RT) in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN). In this non-comparative phase II randomized trial, we evaluated this non-platinum combination with or without bevacizumab, an inhibitor of vascular endothelial growth factor (VEGF).

PATIENTS AND METHODS

Patients with previously untreated stage III-IVB SCCHN were randomized to receive: conventionally fractionated radiation (70 Gy), concurrent cetuximab, and concurrent pemetrexed (arm A); or the identical regimen plus concurrent bevacizumab followed by bevacizumab maintenance for 24 weeks (arm B). The primary end point was 2-year progression-free survival (PFS), with each arm compared with historical control. Exploratory analyses included the relationship of established prognostic factors to PFS and quality of life (QoL).

RESULTS

Seventy-eight patients were randomized: 66 oropharynx (42 HPV-positive, 15 HPV-negative, 9 unknown) and 12 larynx; 38 (49%) had heavy tobacco exposure. Two-year PFS was 79% [90% confidence interval (CI) 0.69-0.92; P < 0.0001] for arm A and 75% (90% CI 0.64-0.88; P < 0.0001) for arm B, both higher than historical control. No differences in PFS were observed for stage, tobacco history, HPV status, or type of center (community versus academic). A significantly increased rate of hemorrhage occurred in arm B. SCCHN-specific QoL declined acutely, with marked improvement but residual symptom burden 1 year post-treatment.

CONCLUSIONS

RT with a concurrent non-platinum regimen of cetuximab and pemetrexed is feasible in academic and community settings, demonstrating expected toxicities and promising efficacy. Adding bevacizumab increased toxicity without apparent improvement in efficacy, countering the hypothesis that dual EGFR-VEGF targeting would overcome radiation resistance, and enhance clinical benefit. Further development of cetuximab, pemetrexed, and RT will require additional prospective study in defined, high-risk populations where treatment intensification is justified.

The degree of intratumor mutational heterogeneity varies by primary tumor sub-site

In an era where mutational profiles inform treatment options, it is critical to know the extent to which tumor biopsies represent the molecular profile of the primary and metastatic tumor. Head and neck squamous cell carcinoma (HNSCC) arise primarily in the mucosal lining of oral cavity and oropharynx. Despite aggressive therapy the 5-year survival rate is at 50%. The primary objective of this study is to characterize the degree of intratumor mutational heterogeneity in HNSCC. We used multi-region sequencing of paired primary and metastatic tumor DNA of 24 spatially distinct samples from seven patients with HNSCC of larynx, floor of the mouth (FOM) or oral tongue. Full length, in-depth sequencing of 202 genes implicated in cancer was carried out. Larynx and FOM tumors had more than 69.2% unique SNVs between the paired primary and metastatic lesions. In contrast, the oral tongue HNSCC had only 33.3% unique SNVs across multiple sites. In addition, HNSCC of the oral tongue had fewer mutations than larynx and FOM tumors. These findings were validated on the Affymetrix whole genome 6.0 array platform and were consistent with data from The Cancer Genome Atlas (TCGA). This is the first report demonstrating differences in mutational heterogeneity varying by subsite in HNSCC. The heterogeneity within laryngeal tumor specimens may lead to an underestimation of the genetic abnormalities within tumors and may foster resistance to standard treatment protocols. These findings are relevant to investigators and clinicians developing personalized cancer treatments based on identification of specific mutations in tumor biopsies.

Early Oral Tongue Squamous Cell Carcinoma: Sampling of Margins From Tumor Bed and Worse Local Control

IMPORTANCE

Positive margins are associated with poor prognosis among patients with oral tongue squamous cell carcinoma (SCC). However, wide variation exists in the margin sampling technique.

OBJECTIVE

To determine the effect of the margin sampling technique on local recurrence (LR) in patients with stage I or II oral tongue SCC.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective study was conducted from January 1, 1986, to December 31, 2012, in 5 tertiary care centers following tumor resection and elective neck dissection in 280 patients with pathologic (p)T1-2 pN0 oral tongue SCC. Analysis was conducted from June 1, 2013, to January 20, 2015.

INTERVENTIONS

In group 1 (n = 119), tumor bed margins were not sampled. In group 2 (n = 61), margins were examined from the glossectomy specimen, found to be positive or suboptimal, and revised with additional tumor bed margins. In group 3 (n = 100), margins were primarily sampled from the tumor bed without preceding examination of the glossectomy specimen. The margin status (both as a binary [positive vs negative] and continuous [distance to the margin in millimeters] variable) and other clinicopathologic parameters were compared across the 3 groups and correlated with LR.

MAIN OUTCOMES AND MEASURES

Local recurrence.

RESULTS

Age, sex, pT stage, lymphovascular or perineural invasion, and adjuvant radiation treatment were similar across the 3 groups. The probability of LR-free survival at 3 years was 0.9 and 0.8 in groups 1 and 3, respectively (P = .03). The frequency of positive glossectomy margins was lowest in group 1 (9 of 117 [7.7%]) compared with groups 2 and 3 (28 of 61 [45.9%] and 23 of 95 [24.2%], respectively) (P < .001). Even after excluding cases with positive margins, the median distance to the closest margin was significantly narrower in group 3 (2 mm) compared with group 1 (3 mm) (P = .008). The status (positive vs negative) of margins obtained from the glossectomy specimen correlated with LR (P = .007), while the status of tumor bed margins did not. The status of the tumor bed margin was 24% sensitive (95% CI, 16%-34%) and 92% specific (95% CI, 85%-97%) for detecting a positive glossectomy margin.

CONCLUSIONS AND RELEVANCE

The margin sampling technique affects local control in patients with oral tongue SCC. Reliance on margin sampling from the tumor bed is associated with worse local control, most likely owing to narrower margin clearance and greater incidence of positive margins. A resection specimen-based margin assessment is recommended.

JAK kinase inhibition abrogates STAT3 activation and head and neck squamous cell carcinoma tumor growth

Aberrant activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) 3 has been implicated in cell proliferation and survival of many cancers including head and neck squamous cell carcinoma (HNSCC). AZD1480, an orally active pharmacologic inhibitor of JAK1/JAK2, has been tested in several cancer models. In the present study, the in vitro and in vivo effects of AZD1480 were evaluated in HNSCC preclinical models to test the potential use of JAK kinase inhibition for HNSCC therapy. AZD1480 treatment decreased HNSCC proliferation in HNSCC cell lines with half maximal effective concentration (EC₅₀) values ranging from 0.9 to 4 μM in conjunction with reduction of pSTAT3_Tyr705 expression. In vivo antitumor efficacy of AZD1480 was demonstrated in patient-derived xenograft (PDX) models derived from two independent HNSCC tumors. Oral administration of AZD1480 reduced tumor growth in conjunction with decreased pSTAT3_Tyr705 expression that was observed in both PDX models. These findings suggest that the JAK1/2 inhibitors abrogate STAT3 signaling and may be effective in HNSCC treatment approaches.

Genetic landscape of metastatic and recurrent head and neck squamous cell carcinoma

BACKGROUND

Recurrence and/or metastasis occurs in more than half of patients with head and neck squamous cell carcinoma (HNSCC), and these events pose the greatest threats to long-term survival. We set out to identify genetic alterations that underlie recurrent/metastatic HNSCC.

METHODS

Whole-exome sequencing (WES) was performed on genomic DNA extracted from fresh-frozen whole blood and patient-matched tumor pairs from 13 HNSCC patients with synchronous lymph node metastases and 10 patients with metachronous recurrent tumors. Mutational concordance within and between tumor pairs was used to analyze the spatiotemporal evolution of HNSCC in individual patients and to identify potential therapeutic targets for functional evaluation.

RESULTS

Approximately 86% and 60% of single somatic nucleotide variants (SSNVs) identified in synchronous nodal metastases and metachronous recurrent tumors, respectively, were transmitted from the primary index tumor. Genes that were mutated in more than one metastatic or recurrent tumor, but not in the respective primary tumors, include C17orf104, inositol 1,4,5-trisphosphate receptor, type 3 (ITPR3), and discoidin domain receptor tyrosine kinase 2 (DDR2). Select DDR2 mutations have been shown to confer enhanced sensitivity to SRC-family kinase (SFK) inhibitors in other malignancies. Similarly, HNSCC cell lines harboring endogenous and engineered DDR2 mutations were more sensitive to the SFK inhibitor dasatinib than those with WT DDR2.

CONCLUSION

In this WES study of patient-matched tumor pairs in HNSCC, we found synchronous lymph node metastases to be genetically more similar to their paired index primary tumors than metachronous recurrent tumors. This study outlines a compendium of somatic mutations in primary, metastatic, and/or recurrent HNSCC cancers, with potential implications for precision medicine approaches.

FUNDING

National Cancer Institute, American Cancer Society, Agency for Science, Technology and Research of Singapore, and Gilead Sciences Inc.

The SWI/SNF ATPases Are Required for Triple Negative Breast Cancer Cell Proliferation

The Brahma (BRM) and Brahma-related Gene 1 (BRG1) ATPases are highly conserved homologs that catalyze the chromatin remodeling functions of the multi-subunit human SWI/SNF chromatin remodeling enzymes in a mutually exclusive manner. SWI/SNF enzyme subunits are mutated or missing in many cancer types, but are overexpressed without apparent mutation in other cancers. Here, we report that both BRG1 and BRM are overexpressed in most primary breast cancers independent of the tumor's receptor status. Knockdown of either ATPase in a triple negative breast cancer cell line reduced tumor formation in vivo and cell proliferation in vitro. Fewer cells in S phase and an extended cell cycle progression time were observed without any indication of apoptosis, senescence, or alterations in migration or attachment properties. Combined knockdown of BRM and BRG1 showed additive effects in the reduction of cell proliferation and time required for completion of cell cycle, suggesting that these enzymes promote cell cycle progression through independent mechanisms. Knockout of BRG1 or BRM using CRISPR/Cas9 technology resulted in the loss of viability, consistent with a requirement for both enzymes in triple negative breast cancer cells.

Salivary duct carcinoma and the concept of early carcinoma ex pleomorphic adenoma

AIMS

The data on the histological type of carcinomatous component and the extent of extracapsular invasion for salivary carcinomas ex pleomorphic adenoma (PA) are conflicting. We aimed to determine the prognostic value of extracapsular invasion in salivary duct carcinomas (SDC) ex PA.

METHODS AND RESULTS

A total of 117 patients with SDC were identified retrospectively; 44 cases involving major salivary glands had pre-existing PA (44 of 117, 37%). The morphological spectrum of SDC ex PA was characterized. The primary endpoint was overall survival (OS). Most SDC ex PA were widely invasive at presentation (27 of 44; 61%). Five patients with intracapsular SDC ex PA experienced no disease progression. The assessment of extracapsular invasion was precluded in eight cases (e.g. positive margins of resection). The rate of lymph node involvement was similar in cases with extracapsular invasion of ≤2 mm (two of three) and >7 mm (22 of 26). Only pT correlated with OS [116 months, 95% confidence interval (CI) 22-210 months for pT1 versus 20 months (95% CI 6-34) for pT4; P = 0.013].

CONCLUSIONS

Intracapsular SDC ex PA are potentially indolent. SDC ex PA with extracapsular invasion of ≤2 mm are rare, and appear to be clinically aggressive. Several histological parameters preclude assessment of extracapsular invasion.

Hotspot activating PRKD1 somatic mutations in polymorphous low-grade adenocarcinomas of the salivary glands

Polymorphous low-grade adenocarcinoma (PLGA) is the second most frequent type of malignant tumor of the minor salivary glands. We identified PRKD1 hotspot mutations encoding p.Glu710Asp in 72.9% of PLGAs but not in other salivary gland tumors. Functional studies demonstrated that this kinase-activating alteration likely constitutes a driver of PLGA.

Thyroid nodules with KRAS mutations are different from nodules with NRAS and HRAS mutations with regard to cytopathologic and histopathologic outcome characteristics

BACKGROUND

Mutations in the RAS gene in the thyroid gland result in the activation of signaling pathways and are associated with a follicular growth pattern and the probability of a carcinoma outcome ranging from 74% to 87%. In the current study, the authors investigated the cytopathologic and histopathologic features of common RAS mutation subtypes.

METHODS

Malignant, indeterminate, and selected benign thyroid cytology cases were tested prospectively for the presence of NRAS61, HRAS61, and KRAS12/13 mutations. For each case, the Bethesda System for thyroid cytopathology diagnosis, additional cytologic descriptors, and surgical pathology outcomes were documented. The Fisher exact test and Wilcoxon 2-sample test were used for statistical comparison between the groups.

RESULTS

A total of 204 thyroid fine-needle aspiration cases with RAS mutations (93.6% of which were associated with indeterminate cytopathology diagnoses) and corresponding surgical pathology resection specimens were identified. The KRAS12/13 mutation was associated with a significantly lower carcinoma outcome (41.7%) when compared with HRAS61 (95.5%) and NRAS61 (86.8%) mutations (P<.0001). Furthermore, oncocytic change was observed in a significantly higher percentage of cytology and resection specimens with KRAS12/13 mutations (66.7% and 75.0%, respectively) in comparison with those with HRAS61 (4.5% and 4.5%, respectively) and NRAS61 (15.4% and 14.7%, respectively) mutations (P<.0001). RAS mutations also were identified in cases of poorly differentiated carcinoma (NRAS61), anaplastic carcinoma (HRAS61), and medullary thyroid carcinoma (HRAS61 and KRAS12/13).

CONCLUSIONS

Subclassification of RAS mutations in conjunction with cytopathologic evaluation improves presurgical risk stratification, provides better insight into lesional characteristics, and may influence patient management. In particular, KRAS12/13-mutated thyroid nodules were found to be different from HRAS61-mutated and NRAS61-mutated nodules with regard to cytopathologic and surgical outcome characteristics.

Novel PRKD gene rearrangements and variant fusions in cribriform adenocarcinoma of salivary gland origin

Polymorphous low-grade adenocarcinoma (PLGA) and cribriform adenocarcinoma of minor salivary gland (CAMSG) are low-grade carcinomas arising most often in oral cavity and oropharynx, respectively. Controversy exists as to whether these tumors represent separate entities or variants of one spectrum, as they appear to have significant overlap, but also clinicopathologic differences. As many salivary carcinomas harbor recurrent translocations, paired-end RNA sequencing and FusionSeq data analysis was applied for novel fusion discovery on two CAMSGs and two PLGAs. Validated rearrangements were then screened by fluorescence in situ hybridization (FISH) in 60 cases. Histologic classification was performed without knowledge of fusion status and included: 21 CAMSG, 18 classic PLGA, and 21 with "mixed/indeterminate" features. The RNAseq of 2 CAMSGs showed ARID1A-PRKD1 and DDX3X-PRKD1 fusions, respectively, while no fusion candidates were identified in two PLGAs. FISH for PRKD1 rearrangements identified 11 additional cases (22%), two more showing ARID1A-PRKD1 fusions. As PRKD2 and PRKD3 share similar functions with PRKD1 in the diacylglycerol and protein kinase C signal transduction pathway, we expanded the investigation for these genes by FISH. Six additional cases each showed PRKD2 and PRKD3 rearrangements. Of the 26 (43%) fusion-positive tumors, there were 16 (80%) CAMSGs and 9 (45%) indeterminate cases. A PRKD2 rearrangement was detected in one PLGA (6%). We describe novel and recurrent gene rearrangements in PRKD1-3 primarily in CAMSG, suggesting a possible pathogenetic dichotomy from "classic" PLGA. However, the presence of similar genetic findings in half of the indeterminate cases and a single PLGA suggests a possible shared pathogenesis for these tumor types.