Programmed death-ligand 1(PD-L1) expression on tumor cells is emerging as a potential predictive biomarker in anti-PD-L1 directed cancer immunotherapy. We analyzed PD-L1 expression in papillary thyroid carcinoma (PTC) and its variants and determined its prognostic potential to predict clinical outcome in these patients. This study was conducted at an academic oncology hospital which is a prime referral centre for thyroid diseases. Immunohistochemical subcellular localization (IHC) analyses of PD-L1 protein was retrospectively performed on 251 archived formalin fixed and paraffin embedded (FFPE) surgical tissues (66 benign thyroid nodules and 185 PTCs) using a rabbit monoclonal anti-PD-L1 antibody (E1L3N, Cell Signaling Technology) and detected using VECTASTAIN rapid protocol with diaminobenzidine (DAB) as the chromogen. The clinical-pathological factors and disease outcome over 190 months were assessed; immunohistochemical subcellular localization of PD-L1 was correlated with disease free survival (DFS) using Kaplan Meier survival and Cox multivariate regression analysis. Increased PD-L1 immunostaining was predominantly localized in cytoplasm and occasionally in plasma membrane of tumor cells. Among all combined stages of PTC, patients with increased PD-L1 membrane or cytoplasmic positivity had significantly shorter median DFS (36 months and 49 months respectively) as compared to those with PD-L1 negative tumors (DFS, both 186 months with p < 0.001 and p < 0.01 respectively). Comparison of PD-L1+ and PD-L1− patients with matched staging showed increased cytoplasmic positivity in all four stages of PTC that correlated with a greater risk of recurrence and a poor prognosis, but increased membrane positivity significantly correlated with a greater risk of metastasis or death only in Stage IV patients. In conclusion, PD-L1 positive expression in PTC correlates with a greater risk of recurrence and shortened disease free survival supporting its potential application as a prognostic marker for PTC.

BackgroundProteolytic cleavage of the extracellular domain (EpEx) of Epithelial cell adhesion molecule (EpCAM) and nuclear signaling by its intracellular oncogenic domain Ep-ICD has recently been implicated in increased proliferation of cancer cells. The clinical significance of Ep-ICD in human tumors remains an enigma.MethodsEpEx, Ep-ICD and β-catenin immunohistochemistry using specific antibodies was conducted on 58 archived thyroid cancer (TC) tissue blocks from 34 patients and correlated with survival analysis of these patients for up to 17 years.ResultsThe anaplastic (ATC) and aggressive thyroid cancers showed loss of EpEx and increased nuclear and cytoplasmic accumulation of Ep-ICD. In contrast, the low grade papillary thyroid cancers (PTC) showed membranous EpEx and no detectable nuclear Ep-ICD. The ATC also showed concomitant nuclear expression of Ep-ICD and β-catenin. Kaplan-Meier Survival analysis revealed reduced overall survival (OS) for TC patients showing nuclear Ep-ICD expression or loss of membranous EpEx (p < 0.0004), median OS = 5 months as compared to 198 months for patients who did not show nuclear Ep-ICD or demonstrated only membranous EpE.ConclusionWe report reciprocal loss of membrane EpEx but increased nuclear and cytoplasmic accumulation of Ep-ICD in aggressive TC; nuclear Ep-ICD correlated with poor OS of TC patients. Thus nuclear Ep-ICD localization may serve as a useful biomarker for aggressive TC and may represent a novel diagnostic, prognostic and therapeutic target for aggressive TC.

BACKGROUND.The authors have previously shown that overexpression of claudin 1 (CLDN1) is associated with advanced disease stage in oral squamous cell carcinomas (OSCCs). Their goal was to examine CLDN1 expression in a large series of primary OSCCs and to further investigate whether CLDN1 overexpression plays a role in invasion in OSCC.METHODS.CLDN1 gene expression levels were determined by quantitative real‐time reverse transcription polymerase chain reaction (QRT‐PCR) in 100 primary OSCCs. CLDN1 protein expression was examined by immunohistochemistry in 70 of 100 OSCCs. E‐Cadherin protein levels were also assessed in 58 OSCCs. The authors performed a transwell Matrigel invasion assay for assessment of the invasive potential of CLDN1 overexpressing oral carcinoma cells. Western blotting and QRT‐PCR were used to assess CLDN1 expression in transfected cells and controls.RESULTS.CLDN1 mRNA was increased (median = 18.5) in 79 of 100 OSCCs, compared with normal oral mucosa (expression = 1.0). CLDN1 overexpression was associated with angiolymphatic (P = .037) and perineural invasion (P = .051). CLDN1 was highly expressed in 48 of 70 (68%) OSCCs. E‐Cadherin was lost or underexpressed in 49 of 58 (84%) OSCCs. The invasion assay showed that cells overexpressing CLDN1 have increased invasive potential, whereas small interfering RNA–mediated depletion of CLDN1 decreased the invasive potential of cells.CONCLUSIONS.CLDN1 overexpression is associated with angiolymphatic and perineural invasion, consistent with aggressive tumor behavior. Overexpression of CLDN1 protein is associated with increased invasiveness of oral carcinoma cells. Cancer 2008. © 2008 American Cancer Society.

BackgroundThe noninvasive Encapsulated follicular variant of papillary thyroid cancer (EFVPTC) has been reclassified as Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) without a significant risk for malignant behavior. However the evaluation remains a challenge for clinicians. We sought to determine whether programmed death-ligand 1 (PD-L1) expression may serve as a biomarker to predict invasiveness of EFVPTC and assist to distinguish these neoplasms from NIFTP.MethodsImmunohistochemical staining of PD-L1 expression was performed in sections of 174 Formalin-fixed paraffin-embedded (FFPE) tissue blocks from surgery removed thyroid nodules.ResultsCytoplasmic PD-L1 expression was significantly increased in invasive EFVPTC (4.76 ± 1.49) as compared to NIFTP (3.06 ± 2.16, p < 0.001). Increased cytoplasmic PD-L1 expression was associated with invasiveness in EFVPTC (p < 0.001); PD-L1 positive EFVPTC cases were at 3.16 folds higher risk in developing invasion than the PD-L1 negative cases. No significant difference in cytoplasmic PD-L1 expression was observed between NIFTP and benign nodules.ConclusionPD-L1 expression may serve as a useful biomarker in predicting invasiveness of EFVPTC and distinguishing NIFTP from invasive EFVPTC. To our knowledge this is the first report suggesting the application of a protein biomarker to confirm NIFTP as benign indolent neoplasms.

Hyalinizing trabecular tumors of the thyroid are interesting but uncommon neoplasms. They have been classified as benign hyalinizing trabecular adenomas or malignant hyalinizing trabecular carcinomas. They share both epidemiologic and morphologic features with papillary carcinoma, and there has been much speculation about the relationship between these two entities. Because RET/PTC gene rearrangements are specific to papillary thyroid carcinoma, the authors examined the presence of RET/PTC-1, -2, and -3 in eight hyalinizing trabecular tumors using reverse transcription-polymerase chain reaction with Southern hybridization and immunohistochemistry. They detected the presence of a RET/PTC gene rearrangement in six of the eight hyalinizing trabecular tumors. This confirms the long-standing suspicion that hyalinizing trabecular tumors do indeed represent a morphologic variant of papillary carcinoma.

The most prevalent risk factors in the development of head-and-neck squamous-cell carcinoma (HNSCC) are excessive tobacco and alcohol consumption. In young patients with HNSCC, these risk factors are often absent. Our purpose was to investigate the risk factors, microsatellite instability (MSI) changes and status of the mismatch repair genes hMLH1 and hMSH2 in a cohort of young patients with HNSCC. Fifty-seven HNSCC tumors were examined for the presence of MSI at 16 microsatellite sites using PCR. In the young patient group (24 cases, <44 years old), 100% of tumors had MSI at 1 site at least and 88% had MSI at 2 or more loci. In older patients (33 cases, >45 years), MSI at 1 or more sites was found in 61% of tumors (young vs. old, p ‫؍‬ 0.0003) and instability at 2 or more sites was found in 36% of tumors (young vs. old, p ‫؍‬ 0.0001). The involvement of the mismatch repair genes was investigated by examining promoter methylation, exon mutation and gene expression of hMLH1 and hMSH2. All results were negative, indicating that inactivation of these 2 genes does not play a role in the development of MSI in tumors from this patient group. Furthermore, the young patient group had a significantly lower incidence of smoking (46% young, 88% old; p ‫؍‬ 0.001) and alcohol consumption (33% young, 67% old; p ‫؍‬ 0.0169), emphasizing the probable importance of other environmental and/or genetic factors in the development of their disease. © 2001 Wiley-Liss, Inc. Key words: microsatellite instability; hMLH1; hMSH2; squamouscell carcinoma; head-and-neck cancerHead-and-neck squamous-cell carcinoma (HNSCC) is a relatively common neoplasm, accounting for 2% to 7% of all tumors in the Western Hemisphere. 1,2 The most prevalent risk factors in this cancer are excessive tobacco and alcohol consumption. 3 However, in young patients with HNSCC, these risk factors are not always present, implicating other factors in the etiology of their disease. Microsatellite sequences are 2 to 5 nucleotide repeats that can be found scattered throughout the eukaryotic genome. They have been widely used as genetic markers due to their high degree of polymorphism. Microsatellite instability (MSI) is characterized by expansion or contraction in the length of short tandem repeats and has been associated with various cancer types and inheritable diseases. MSI was initially described in hereditary non-polyposis colorectal cancer (HNPCC) as well as in sporadic colorectal tumors. 4 In HNPCC, a replication error phenotype (RER ϩ ) has been associated with mutations in the hMSH2, hMLH1, hPMS1 and hPMS2 genes, which are involved in mismatch repair (MMR) mechanisms. 4 -7 The RER ϩ phenotype has also been described in other tumor types, such as gastric, 8 -13 lung, 14,15 ovary, 16,17 pancreatic, 18 endometrial 19,20 and HNSCC. [21][22][23][24][25][26][27] MSI in head-and-neck carcinoma has been found in tumors at a frequency of 7% to 30%. 21,25,28 Head-and-neck tumors generally occur in older men (Ͼ50 years) with a history of smoking and/or alcohol abuse. As in...

In this small study, a combinatorial analysis using SKY, CGH, and microarray provides a model linking the changes in gene expression to changes in chromosomal dosage and structure. This approach has identified a subset of genetic changes that provide new opportunities for investigating the genetic basis of tumorigenesis in HNSCC.

Basaloid squamous cell carcinoma is a recently recognized variant of squamous cell carcinoma. The lesion is histologically distinctive and manifests a predilection for the supraglottis, pyriform sinus, and tongue base. The immunohistochemical profile is discussed. The differential diagnoses include adenoid cystic carcinoma, small cell neuroendocrine carcinoma, basal cell adenocarcinoma, adenosquamous carcinoma, squamous cell carcinoma, spindle cell squamous carcinoma, mucoepidermoid carcinoma, and adenoid squamous cell carcinoma. Basaloid squamous cell carcinoma is a biologically high-grade tumor with a propensity for nodal as well as systemic metastases. It is a morphologic and phenotypic entity with a separate prognostic significance.