Correlation of Protease-Activated Receptor-1 With Differentiation Markers in Squamous Cell Carcinoma of the Head and Neck and Its Implication in Lymph Node Metastasis

PURPOSE

Protease-activated receptor-1 (PAR-1) is a G-protein-coupled receptor that contributes to multiple signal transduction pathways. Although the functions of PAR-1 in many normal cells, such as platelets and astrocytes, have been well studied, its roles in cancer progression and metastasis have not been fully elucidated, and studies to date appear contradictory.

EXPERIMENTAL DESIGN

To clarify the function of PAR-1 in metastasis of squamous cell carcinoma of the head and neck (SCCHN), we examined PAR-1 expression in clinical specimens by immunohistochemistry and in SCCHN cell lines by immunoblotting. Furthermore, par-1 cDNA-transfected SCCHN cell lines were also used to verify PAR-1-mediated pathway.

RESULTS

The metastatic tumors showed a lower percentage of PAR-1-positive cells (46%) and lower levels of PAR-1 expression (median weight index = 10) than node negative primary tumors (80% and median weight index = 60, respectively). In addition, expression level of PAR-1 positively correlated with levels of keratinocyte differentiation markers keratin-1, -10, and -11. Additional studies using sense and antisense par-1 cDNA-transfected SCCHN cell lines illustrated that the presence of PAR-1 was required for the expression of involucrin, a keratinocyte differentiation marker. PAR-1 expression also contributes to activation of the mitogen-activated protein kinase (MAPK) pathway. Blocking MAPK activation by a mitogen-activated protein/extracellular signal-regulated kinase inhibitor, not by a phosphatidylinositol 3'-kinase inhibitor, reduced level of involucrin, suggesting that regulation of involucrin by PAR-1 is partially through the MAPK signaling pathway.

CONCLUSIONS

Our study suggests that PAR-1 signaling induces differentiation markers in SCCHN cells, and its expression is conversely correlated with cervical lymph node metastasis.

Microdissection Techniques for Molecular Testing in Surgical Pathology

Objective.—To describe the techniques for microdissection of paraffin-embedded and frozen tissue sections for the use in molecular applications.

Data Sources.—Original research papers and review papers and the authors' personal experiences.

Data Synthesis.—Manual and laser-capture microdissection are described in detail, with specific protocols for sample preparation and instructions for performing the microdissection. A section addressing frequently asked questions is also included.

Conclusions.—Microdissection is a technique that is very useful both in the research setting and for clinical molecular testing in paraffin-embedded tissue samples. The available techniques range from simple and inexpensive (manual microdissection) to complex and expensive (laser-capture microdissection). All of the techniques, however, require the user to be familiar with microscopy and histology.

Tumor suppressor gene allelic loss profiles of the variants of papillary thyroid carcinoma

Papillary thyroid carcinoma (PTCa) is a relatively common, indolent tumor that usually has an excellent prognosis. While the diagnosis of conventional PTCa is relatively straightforward, encapsulated tumors with follicular growth pattern and unusual or incomplete cytologic features of papillary carcinoma can be diagnostically challenging. Encapsulated, noninvasive tumors are particularly controversial as the differential diagnosis includes a nonneoplastic nodule, a benign follicular adenoma, and papillary carcinoma. In this study, we performed molecular genotyping to identify loss of heterozygosity of tumor suppressor genes in conventional PTCa and in several different morphologic variants, including follicular variant, tall cell variant, and oncocytic variant. Our data demonstrate that conventional PTCas have the lowest frequency of allelic loss (7%), as compared with follicular, oncocytic, and tall cell variants (19%, 34%, and 20%, respectively). Frequency of allelic loss increased with increasing size of the tumors, but did not correlate with age, gender, extrathyroidal extension, or lymph node metastases. Though it is unlikely that these results will enable the distinction between different variants of papillary carcinoma, the finding of significant rates ofallelic loss in the variants of PTCa provides additional evidence of malignancy and may be useful in distinguishing encapsulated tumors from nonneoplastic or benign nodules.

Chondrosarcoma of the sphenoid sinus resected by an endoscopic approach

Chondrosarcoma of the sinonasal tract is a rare neoplasm. Surgical excision is usually sufficient for low-grade lesions, whereas combined treatment is usually recommended for high-grade lesions. The oncologic outcome depends on a complete resection as well as the grade of the tumor. We present the case of a 35-year-old man presenting with an incidental finding of a chondrosarcoma of the posterior septum and rostrum of the sphenoid sinus. The tumor was completely resected using a transnasal endoscopic approach obtaining negative margins. Surgery is the mainstay treatment for low-grade chondrosarcomas. In selected patients, complete resection can be achieved using transnasal endoscopic approaches.

Prostatic adenocarcinoma metastatic to the head and neck and the workup of an unknown epithelioid neoplasm

BACKGROUND

Epithelioid tumors in the head and neck are common and include both primary and metastatic lesions. For metastatic lesions, clinical factors, tumor location, and ancillary immunohistochemical studies must be taken into consideration to help the clinician and the pathologist determine the site of origin. One unusual, but important, primary tumor that can metastasize to the head and neck is carcinoma of the prostate (CAP).

METHODS

The files of the University of Pennsylvania Department of Pathology were searched for cases of metastatic CAP. All slides were examined, and clinical information was obtained from the referring physician's patient charts.

RESULTS

We describe 14 cases of metastatic CAP to the head and neck. Six patients had no history of CAP at the time of biopsy of the head and neck metastasis, and only eight patients had other widespread metastatic disease. Histologically, most of the tumors had epithelioid cells with prominent nucleoli and cribriform, solid, or infiltrating single cell growth patterns. PSA and PSAP immunohistochemical stains were positive in all cases. Seven of 12 patients with known follow-up are alive after radiation or hormonal therapy.

CONCLUSIONS

These results demonstrate a fair prognosis with possible prolonged survival with metastatic CAP to the head and neck after appropriate diagnosis and subsequent hormone and radiation therapy. Given this survival advantage with treatment, it is critical to consider the diagnosis of metastatic CAP when evaluating a metastatic malignant epithelioid tumor in the head and neck of an elderly man.

p63 expression in sclerosing mucoepidermoid carcinomas with eosinophilia arising in the thyroid

Primary sclerosing mucoepidermoid carcinomas with eosinophilia (SMECE) of the thyroid gland are rare tumors that can present diagnostic difficulties to the pathologist due to the unusual histologic features. Furthermore, the etiology of these tumors has been debated in the literature, with some authors believing that the tumors arise from remnants of the ultimobranchial body (UBB, solid cell nests) and others proposing that they arise from follicular epithelial cells. Because SMECE often occur in glands with chronic lymphocytic thyroiditis and UBB hyperplasia, and do not stain like follicular or parafollicular cells, it is likely that the tumors do arise from UBB/solid cell nests. In this study, we provide additional evidence for this relationship, by demonstrating that SMECE stain strongly positive for p63, which is a new marker for UBB/solid cell nests.

Expression pattern of chemokine receptor 6 (CCR6) and CCR7 in squamous cell carcinoma of the head and neck identifies a novel metastatic phenotype

Squamous cell carcinoma of the head and neck (SCCHN) metastasizes predictably to cervical lymph nodes, with low rates of distant metastases. Tumor cells can express various receptors that facilitate such metastatic spread to lymph nodes and other nonlymphoid organs. Chemokine receptors (CCR), normally expressed on lymphocytes, control immune and inflammatory cell migration, providing a link between innate and adaptive immunity. Chemokine receptor expression was evaluated in SCCHN, using paired primary and metastatic tumors cell lines, and paired primary and metastatic biopsies from the same patients. Quantitative reverse transcription-PCR showed a consistent pattern of CCR6 down-regulation and up-regulation of CCR7 in metastatic cells and tissues. Chemotaxis assays, ligand-induced receptor down-regulation, and specific antibody blocking experiments supported the quantitative reverse transcription-PCR results, indicating that these surface receptors were functional on metastatic tumor cells. Cells derived from a highly metastatic mouse model of SCCHN were used to confirm CCR7 up-regulation in tumor cells with higher metastatic potential. CCR6 down-regulation is consistent with its decreased expression in cells emigrating from peripheral mucosal sites, whereas CCR7, important for homing of immune cells to secondary lymphoid organs, was significantly up-regulated. Thus, CCR6, CCR7, and their ligands, normally important in controlling immune cell trafficking in response to inflammatory stimuli, may have an important role in determining the metastasis of SCCHN cells in vivo.

Molecular Analysis to Demonstrate That Odontogenic Keratocysts Are Neoplastic

Context.—Odontogenic keratocysts (OKCs) are unique odontogenic lesions that have the potential to behave aggressively, that can recur, and that can be associated with the nevoid basal cell carcinoma syndrome. Whether they are developmental or neoplastic continues to be debated.

Objectives.—To identify loss of heterozygosity of tumor suppressor genes in OKCs and to suggest a pathogenetic origin for these lesions.

Design.—We examined 10 OKCs for loss of heterozygosity of tumor suppressor genes, using a microdissection and semiquantitative genotyping analysis. The genes analyzed included 10 common tumor suppressor genes, as well as the PTCH gene, which is mutated in nevoid basal cell carcinoma syndrome.

Results.—Loss of heterozygosity was seen in 7 of 10 cases, with a frequency between 11% and 80% of the genes studied. The genes that exhibited the most frequent allelic losses were p16, p53, PTCH, and MCC (75%, 66%, 60%, and 60%, respectively). Daughter cysts were associated with a higher frequency of allelic loss (P = .02), but epithelial budding was not.

Conclusions.—Our study indicates that a significant number of OKCs show clonal loss of heterozygosity of common tumor suppressor genes. The finding of clonal deletion mutations of genomic DNA in these cysts supports the hypothesis that they are neoplastic rather than developmental in origin.

Molecular genotyping of medullary thyroid carcinoma can predict tumor recurrence

Medullary thyroid carcinoma can have an aggressive behavior, and little is known about the molecular basis for clinical outcome. Defining risk of recurrent or metastatic disease is difficult, and it has been limited to clinical and pathologic features, such as advanced age, cervical lymph node metastases, and stage at presentation. Using microdissection and genotyping, we studied 11 cases of medullary carcinoma for allelic losses in a panel of known tumor suppressor genes. The tumor suppressor genes with the most frequent allelic losses were NF2, l-myc, and p53 (75%, 44%, and 44%, respectively). The average frequency of allelic loss across all tumors was 44% and was higher in tumors that recurred. A combination of previously described high-risk variables (increased patient age and cervical lymph node metastases) with the frequency of allelic loss yielded a high-risk group, in which 6 of 6 patients recurred, and a low-risk group, in which 0 of 5 patients recurred (P = 0.004). Frequency of allelic loss in tumor suppressor genes may provide a useful adjunctive prognostic test in medullary thyroid carcinoma.

Molecular evidence of anaplastic transformation in coexisting well-differentiated and anaplastic carcinomas of the thyroid

Anaplastic thyroid cancer is a rare but nearly universally fatal tumor. Epidemiologic data suggest that many anaplastic thyroid carcinomas arise from transformation of preexisting or coexisting well-differentiated thyroid carcinomas. At the molecular level, the mutations responsible for the anaplastic transformation are incompletely understood, although the mutational events are thought to involve tumor suppressor genes. To examine transformation from a well-differentiated thyroid carcinoma to anaplastic carcinoma, we studied coexisting well-differentiated (Hürthle cell and papillary carcinoma) and anaplastic tumors with a molecular genotyping panel of tumor suppressor genes associated with thyroid neoplasia. The patterns of allelic loss in our results showed that the majority of cases have a core of conserved mutations in the two morphologically distinct areas and substantial increases in mutation rates in the anaplastic components.

Simultaneous diffuse sclerosis variant of papillary thyroid carcinoma and diffuse toxic hyperplasia (Graves' disease)

Diffuse sclerosis variant of papillary thyroid carcinoma (DSVPTC) is an unusual malignant neoplasm that typically permeates the entire gland resulting in diffuse thyroid enlargement. In the absence of a dominant nodule, DSVPTC can be histologically deceiving because of exuberant inflammation and the scattered distribution of the microscopic tumor islands. The difficulty in diagnosing this tumor is compounded by its rarity and unusual clinical and histologic features. Herein, we describe a unique case of DSVPTC that was clinically masked by a co-existing second diffuse thyroid process--Graves' disease (GD). A subtotal thyroidectomy was performed in a 27-yr-old Caucasian female who presented with symmetrical diffuse thyromegaly with neck compressive symptoms, thyrotoxicosis, and biochemical signs of GD. Histologic examination of the thyroid gland unexpectedly revealed extensive involvement by DSVPTC in addition to the diffuse hyperplastic non-malignant thyroid follicles. This report illustrates the histologic features as well as the diagnostic challenge encountered in a rare simultaneous occurrence of DSVPTC and GD.<P>

Sentinel Lymph Node Biopsy Identifies Occult Nodal Metastases in Patients with Marjolinʼs Ulcer

Since Marjolin's description, the management of burn scar carcinoma has remained controversial. A multitude of options and recommendations exist for the management of both primary lesions and regional nodal metastasis. This work reviews six cases of Marjolin's ulcer staged using sentinel lymph node biopsy. All primary lesions were confirmed to be squamous cell carcinoma and occurred a median of 29.5 years after burn. No patient had clinically detectable lymphadenopathy. In all cases, preoperative lymphoscintigraphy successfully identified a single draining regional nodal basin. Subsequent intraoperative lymphatic mapping/sentinel lymph node (SLN) biopsy was successful in five of six cases (83%). A successful intraoperative lymphatic mapping/SLN biopsy was defined as the identification of blue (uptake of isosulfan blue dye) or "hot" (uptake of radiolabeled sulfur colloid as measured with a handheld gamma counter) node(s) and subsequent excision. Four of five SLN biopsies identified previously occult nodal metastasis. SLN biopsy represents a minimally invasive and accurate staging procedure for Marjolin's ulcer.

Loss of heterozygosity of the VHL gene identifies malignancy and predicts death in follicular thyroid tumors

BACKGROUND

Follicular thyroid tumors (FTT) usually require resection to distinguish adenoma from carcinoma. Better markers that predict histologic subtype and prognosis are needed for FTT.

METHODS

Seventeen benign and malignant FTT with follow-up were selected. Pathologic diagnosis was confirmed, tumor and normal tissue were microdissected, and DNA was extracted. Polymerase chain reaction (PCR) products for a microsatellite marker at the von Hippel Lindau gene (VHL) gene locus (3p26) were analyzed with semiquantitative capillary gel electrophoresis to detect loss of heterozygosity (LOH). Data were assessed for statistical significance with chi(2).

RESULTS

Mean follow-up was 77 months (range 29 to 120 months). Four cases were uninformative (homozygous microsatellite). Among 13 evaluable patients (6 adenomas, 7 follicular cancers) LOH of VHL was present only in carcinomas (P=.013). LOH was present in 4/4 patients with recurrence and 0/3 patients without recurrence (P=.017). Death from disease has occurred in 3 patients. LOH of VHL was strongly associated with death from disease (P=.034).

CONCLUSIONS

FTT can be analyzed for LOH at the VHL gene locus. In this initial study, LOH of VHL was highly specific for malignancy and predicted death from disease. The analysis of VHL may provide for preoperative detection in cytologic samples with potential impact on clinical management of FTT.

Molecular mutations in thyroid carcinogenesis

Molecular mutations in thyroid carcinomas have been well characterized and studied and consist of both germline and somatic genetic events. Mutations that are associated with tumorigenesis can be divided into 2 general categories: oncogene mutations and tumor suppressor gene mutations. Thyroid tumors and their characteristic molecular mutations are discussed in this review. The current practice in diagnostic testing for thyroid tumors also is examined.

Serial Measurements Increase the Accuracy of Laser Doppler Assessment of Burn Wounds

Traditional methods of judging burn depth by clinical evaluation of the wound based on appearance and sensation remain in wide use but are subject to individual variation by examiner. In addition to the clinical difficulties with burn wound management, observer dependency of wound assessment complicates clinical trials of burn wound therapy. A laser Doppler flowmeter with a multichannel probe was used to measure burn wound perfusion as a tool to predict wound outcome. Serial measurement with laser Doppler flowmetry had an 88% specificity and a positive predictive value of 81% for identifying nonhealing wounds. These results suggest that laser Doppler flowmetry is a potentially useful tool for burn wound assessment.

A novel microdissection and genotyping of follicular-derived thyroid tumors to predict aggressiveness

Distinguishing thyroid follicular adenoma from minimally invasive or encapsulated angioinvasive carcinoma can be diagnostically challenging. In some cases, tumors are distorted, fragmented, or stripped of their capsule, and a definitive diagnosis becomes nearly impossible. In other cases, the foci of capsular and/or vascular invasion are subtle, thus making the diagnosis of carcinoma difficult. We developed a microdissection genotyping assay for assessing a panel of tumor-suppressor genes for loss of heterozygosity mutations. The frequency of allelic loss (FAL) in follicular-derived neoplasms correlates with the histologic aggressiveness of the tumor. Furthermore, we calculated the amount of genetic heterogeneity within each tumor, as a second important measure of a tumor's ability for clonal expansion and a surrogate marker for its malignant potential. The follicular adenomas had a low FAL (average 9%) and low intratumoral heterogeneity (5% variability). The minimally invasive and encapsulated angioinvasive carcinomas had an intermediate FAL (average 30%) and intermediate intratumoral heterogeneity (10% variability). The widely invasive carcinomas had a high FAL (average 53%) and high intratumoral heterogeneity (24% variability). Although a larger retrospective study is needed to correlate genotyping studies with patient outcome and prognosis, our results indicate that performing a mutational genotyping assay can stratify tumors into the histologically well-defined categories of adenomas, minimally invasive/angioinvasive carcinomas, and widely invasive follicular carcinomas.

Myoepithelial neoplasia of the submandibular gland: case report and therapeutic considerations

Tumors of the submandibular gland typically arise from the seromucinous acini, which make up the majority of the gland. The most common benign tumor of this structure is the pleomorphic adenoma, whereas the most common malignancy of the submandibular gland is adenoid cystic carcinoma. We describe an unusual case of a neoplastic process of the myoepithelial cells of the submandibular gland in a middle-aged woman. This rare tumor is most commonly diagnosed in the parotid gland and in the minor salivary glands of the hard palate; a review of the literature uncovered only 5 previous reports of myoepithelioma of the submandibular gland. Distinguishing myoepithelioma from benign pleomorphic adenoma and malignant myoepithelial carcinomas can be challenging. Immunohistochemical staining can help to distinguish between the benign neoplasms, but histologic features remain the "gold standard" for diagnosing the malignant tumors. Increasing use of immunohistochemistry panels to assess parotid neoplasms also suggests that myoepithelioma may be underrecognized.

Microscopic papillary thyroid carcinoma compared with clinical carcinomas by loss of heterozygosity mutational profile

The clinical significance of microscopic papillary thyroid carcinoma (PTCa) is controversial. Many authors think that microscopic PTCa (<1 cm) have the same pathogenetic origin as clinically sized papillary carcinomas (>1 cm). Despite the fact that all clinical risk prognostication schemes have the size of the tumor as a primary category, small tumors do have malignant potential and can metastasize. There is growing evidence that small PTCa have the molecular translocations between the proto-oncogene RET and various activating partner genes that are characteristic of clinically sized PTCa. This study used a microdissection and genotyping assay to study the patterns of loss of heterozygosity of tumor suppressor genes in microscopic and clinically sized PTCa. Our results indicate that all PTCa harbor mutations with similar frequencies and distribution patterns, regardless of the size of the tumor. These data are further evidence that microscopic and clinically sized PTCa are pathogenetically related.

A microdissection and molecular genotyping assay to confirm the identity of tissue floaters in paraffin-embedded tissue blocks

CONTEXT

A recurring problem in surgical pathology practice is specimen mix-up and floater contamination. While many cases can be resolved histologically, a significant number remain unclear and may have serious clinical and medicolegal implications.

OBJECTIVES

To design a microdissection and genotyping assay to identify contaminating floater tissues in paraffin-embedded tissues that is optimized for small samples, and to use the assay to resolve a series of clinical cases with floater tissues.

MATERIALS AND METHODS

Twenty-one cases of possible tissue floater contamination in paraffin-embedded tissue blocks were included. Using 4 unstained, 4-microm-thick histologic sections, multiple sites were microdissected under direct visualization either by hand or by laser capture microdissection. Nonneoplastic and neoplastic tissues were sampled. Polymerase chain reaction was performed for a panel of 10 polymorphic microsatellite markers at 1p34, 3p26, 5q21, 9p21, 10q23, and 17p13. Allele size and content were analyzed semiquantitatively by fluorescent capillary electrophoresis, and the genotypes for the tissues in the paraffin-embedded tissue blocks were compared for identity.

RESULTS

Tissue identification was successful in all cases, despite small tissue sample size and fixation effects. Comparative analysis of neoplastic tissue floaters and the presumptive source tumor was performed when possible to control for possible allelic loss or microsatellite instability.

CONCLUSIONS

Microdissection and genotyping are effective and reliable means to objectively resolve problems of possible floater contamination. Even minute tissue samples provide sufficient DNA template for polymerase chain reaction microsatellite analysis. Because of the potential clinical implications of floaters, we recommend that all suspected floaters that would change a diagnosis from benign to malignant be subjected to genotyping assay to confirm the identity of the floater tissue.

Non-tumor-associated psammoma bodies in the thyroid

Psammoma bodies in the thyroid are common in glands with papillary thyroid carcinoma. Psammoma bodies that are not associated with tumor cells, however, represent a diagnostic problem for pathologists. Should we treat isolated psammoma bodies as representing metastatic disease? This study included patients who had non-tumor-associated psammoma bodies in their thyroids or in the perithyroidal lymph nodes. Clinical, pathologic, and follow-up information was obtained for the patients. Our results indicate that 27 of 29 patients had a contralateral or an ipsilateral tumor, the majority of which were papillary. We noted a high frequency of microscopic carcinomas (12/27) and of tall cell variants of papillary thyroid carcinoma (8/27 cases). Based on these findings, we recommend that thyroid glands with non-tumor-associated psammoma bodies and no histologically identified carcinoma be entirely submitted to identify any microscopic carcinoma. If no carcinoma is identified in a lobectomy, discussion with the surgeon should indicate the need for close clinical follow-up.