Candice C. Black

Epithelial-Mesenchymal Transition Markers in Pancreatic Ductal Adenocarcinoma

Objectives: Expression of transcription factors that mediate epithelial-mesenchymal transition (EMT), such as Twist and Slug, is correlated with poor prognosis in many tumor types. Selected EMT markers were studied in a series of pancreatic ductal adenocarcinomas (PDAs) and benign pancreatic tissues to determine whether expression levels correlated with diagnosis, histologic grade, or patient outcome. Methods: Immunohistochemical stains for Twist, Slug, and N-cadherin were performed using a tissue microarray containing 68 PDAs and 38 samples of normal pancreas or chronic pancreatitis tissues. Results: Twist and Slug were identified in both the nucleus and cytoplasm of benign pancreatic ductal epithelium, chronic pancreatitis, and PDA. Compared with normal ductal epithelium, nuclear levels of Twist are decreased in PDA. None of the other EMT markers showed significant differences in staining indices among the diagnostic groups. There were no correlations between EMT marker expression and histologic grade. Epithelial-mesenchymal transition marker expression was not associated with N-cadherin expression, patient outcome, or duration of survival. Conclusions: Decreased expression of nuclear Twist is observed in malignant pancreatic epithelium. However, use of Twist as a diagnostic marker is precluded because decreased expression is also seen in chronic pancreatitis. None of the markers studied were predictive of patient outcome.

Critical evaluation of frozen section margins in head and neck cancer resections

Negative resection margins are likely the most important prognostic factor for a patient with a head and neck squamous cell carcinoma. Frozen‐section evaluation allows a positive margin to be corrected before surgical closure and reconstruction. A final pathology report is later issued after examination of all resected tissues. The accuracy of the final pathology report relies on accuracy in the preceding steps. The current process of margin reporting in head and neck cancer resections was studied to reveal possible waste and error in the system.

Distinguishing pseudoepitheliomatous hyperplasia from squamous cell carcinoma in mucosal biopsy specimens from the head and neck

CONTEXT The differentiation of pseudoepitheliomatous hyperplasia from invasive squamous cell carcinoma is a difficult and frequently encountered distinction, especially in biopsy specimens from head and neck mucosa. The problem is compounded by inflamed and often poorly oriented tissue sections. OBJECTIVE To distinguish pseudoepitheliomatous hyperplasia from invasive squamous cell carcinoma, utilizing a panel of antibodies to various epithelial and stromal elements (p53, matrix metalloproteinase 1, E-cadherin, and collagen IV) that has been shown to be useful in differentiating intestinal adenomas with invasive adenocarcinoma from displaced adenomatous epithelium. DESIGN Thirty-three archival specimens (16 squamous cell carcinoma [12 with invasion and 4 with microinvasion] and 17 pseudoepitheliomatous hyperplasia) from head and neck mucosal locations were immunostained and examined by the authors. RESULTS We found increased nuclear staining of the invasive tumor cells with p53. There was decreased staining within invasive tumor nests with E-cadherin. There was highly significant increased staining within tumor cells and adjacent stroma with matrix metalloproteinase 1 (P < .001). The only antibody in our panel that did not show a reliable staining pattern was collagen IV. It appeared fragmented in benign inflamed and malignant areas and therefore was not useful. CONCLUSIONS p53, matrix metalloproteinase 1, and E-cadherin showed significant staining trends independent of inflammation and suboptimal tissue orientation. Although a properly oriented hematoxylin-eosin-stained section was our gold standard, we found this immunoperoxidase panel useful as a diagnostic adjunct in difficult cases.

Markers of epithelial-mesenchymal transition and epithelial differentiation in sarcomatoid carcinoma: utility in the differential diagnosis with sarcoma.

The distinction between sarcomatoid carcinoma (SC) and bona fide sarcoma can be difficult using conventional immunohistochemical markers. Epithelial-mesenchymal transition (EMT) has been proposed as a histogenetic mechanism for the development of SC. Expression of selected markers of EMT (Twist and Slug) was compared with other markers of epithelial differentiation in SC and spindle cell sarcoma to determine the utility of these antigens in this differential diagnosis. Twenty-seven cases of SC (excluding those of gynecologic origin) were stained by immunohistochemistry for cytokeratins (AE1/AE3, 5D3, CK5/6, and 34βE12), p63, claudin-1, claudin-7, epithelial cadherin, placental cadherin, epithelial cell adhesion molecule/epithelial-specific antigen, 14-3-3σ, Twist, and Slug. A comparison group of 21 spindle or pleomorphic spindle cell sarcomas was also studied. Immunohistochemical stains were scored in a semiquantitative manner and subsequent exploratory analyses were performed using logistic regression and χ2 tests. Only cytokeratin AE1/AE3 specifically labeled SC in a statistically significant manner. Other epithelial-specific markers tested did not distinguish SC from sarcoma primarily owing to low sensitivity. However, when positive, immunostains such as CK5/6, membranous epithelial cadherin, and nuclear p63 may aid in the distinction of SC from sarcoma. EMT markers were expressed in most cases of both SC and sarcoma, and were not useful in making a differential diagnosis between these neoplasms.

Use of a linear array for the detection of human papillomavirus genotypes in head and neck cancer.

CONTEXT Tumors of the head and neck commonly arise from the squamous and respiratory mucosa that lines the nasal and oral cavity, sinuses, pharynx, and larynx. The rate of oropharyngeal cancers diagnosed among Americans younger than 50 years is increasing. Infection of the oropharynx and tonsils by the human papillomavirus (HPV) has been linked to preneoplasia and cancer. OBJECTIVES To evaluate the Roche Linear Array HPV Genotyping test kit to identify, and then specifically genotype, HPV in formalin-fixed, paraffin-embedded tissues. DESIGN We evaluated the performance of this assay for accuracy, for intra-assay and interassay precision, and for its limit of detection, using materials with known HPV status. Sixteen tumor tissues with the following origins were evaluated: 1 ocular, 1 hypopharynx, 8 tonsil, 1 retromolar trigone, 3 tongue, 1 anal, and 1 lymph node. DNA from formalin-fixed, paraffin-embedded tumor sections was isolated and amplified in duplicate, with positive and negative controls, using primers specific to the polymorphic L1 region of the HPV genome. Thirty-seven genotypes were tested using the linear array. The amplified product (450 base pairs) was visualized by gel electrophoresis and, if positive, reflexed to HPV genotyping. RESULTS Nine of the 16 tumors analyzed were HPV positive. The detected genotypes included HPV 6, 16, and 69. CONCLUSIONS The Roche Linear Array HPV Genotyping test is an easy-to-use method for determining HPV genotype in the routine analysis of formalin-fixed, paraffin-embedded tumors. This assay is robust and can be performed routinely in a clinical laboratory setting.

Filamentous fungal carbon catabolite repression supports metabolic plasticity and stress responses essential for disease progression

Aspergillus fumigatus is responsible for a disproportionate number of invasive mycosis cases relative to other common filamentous fungi. While many fungal factors critical for infection establishment are known, genes essential for disease persistence and progression are ill defined. We propose that fungal factors that promote navigation of the rapidly changing nutrient and structural landscape characteristic of disease progression represent untapped clinically relevant therapeutic targets. To this end, we find that A. fumigatus requires a carbon catabolite repression (CCR) mediated genetic network to support in vivo fungal fitness and disease progression. While CCR as mediated by the transcriptional repressor CreA is not required for pulmonary infection establishment, loss of CCR inhibits fungal metabolic plasticity and the ability to thrive in the dynamic infection microenvironment. Our results suggest a model whereby CCR in an environmental filamentous fungus is dispensable for initiation of pulmonary infection but essential for infection maintenance and disease progression. Conceptually, we argue these data provide a foundation for additional studies on fungal factors required to support fungal fitness and disease progression and term such genes and factors, DPFs (disease progression factors).

Clinical Genotyping of Non–Small Cell Lung Cancers Using Targeted Next-Generation Sequencing: Utility of Identifying Rare and Co-mutations in Oncogenic Driver Genes

Detection of somatic mutations in non–small cell lung cancers (NSCLCs), especially adenocarcinomas, is important for directing patient care when targeted therapy is available. Here, we present our experience with genotyping NSCLC using the Ion Torrent Personal Genome Machine (PGM) and the AmpliSeq Cancer Hotspot Panel v2. We tested 453 NSCLC samples from 407 individual patients using the 50 gene AmpliSeq Cancer Hotspot Panel v2 from May 2013 to July 2015. Using 10 ng of DNA, up to 11 samples were simultaneously sequenced on the Ion Torrent PGM (316 and 318 chips). We identified variants with the Ion Torrent Variant Caller Plugin, and Golden Helixs SVS software was used for annotation and prediction of the significance of the variants. Three hundred ninety-eight samples were successfully sequenced (12.1% failure rate). In all, 633 variants in 41 genes were detected with a median of 2 (range of 0 to 7) variants per sample. Mutations detected in BRAF, EGFR, ERBB2, KRAS, NRAS, and PIK3CA were considered potentially actionable and were identified in 237 samples, most commonly in KRAS (37.9%), EGFR (11.1%), BRAF (4.8%), and PIK3CA (4.3%). In our patient population, all mutations in EGFR, KRAS, and BRAF were mutually exclusive. The Ion Torrent Ampliseq technology can be utilized on small biopsy and cytology specimens, requires very little input DNA, and can be applied in clinical laboratories for genotyping of NSCLC. This targeted next-generation sequencing approach allows for detection of common and also rare mutations that are clinically actionable in multiple patients simultaneously.

Spatial and temporal distributions of lung cancer histopathology in the state of Maine

Maine has among the highest rates of lung cancer in the United States (US). Maine serves as a geographical representation of US rural communities, and their associated health disparities. As the key risks of tobacco use decrease and radon abatement increases, previously obscured environmental exposures may measurably contribute to the attributable risk fraction of lung cancer. To generate hypotheses of novel environmental exposures associated with lung cancer, we investigated if there was non-random spatial distribution of lung cancer in Maine. Case data (n = 14,038) between 1995 and 2006 were obtained from the Maine Cancer Registry. Population data were obtained from the 2000 US Census. We assessed the spatial distribution of lung cancers among white cases by histopathology subtype [non-small cell lung carcinoma (NSCLC): adenocarcinoma (n = 3680), squamous cell (n = 2801) and large cell (n = 1195); and small cell lung carcinoma (SCLC) (n = 1994)], using spatial scan statistic, assuming a discrete Poisson distribution adjusted for age and population density. Because of time-dependent trends in lung cancer differential diagnostic criteria, we repeated our analyses, limiting it to 2002-2006. While SCLC rates were equivalent across the state, we identified discrete regions with elevated rates of adenocarcinoma among females and squamous cell carcinoma among males. Independent of gender, the most striking geospatial observation was elevated large cell lung cancer specifically in one of the poorest counties in the US. A selective spatial distribution of large cell lung cancer has not been previously reported. More research is needed to identify factors inducing large cell carcinoma pathology, and to determine if in rural communities health disparities are associated with increased risk for this diagnosis.

Haemophilus influenzae Lymphadenopathy in a Patient With Agammaglobulinemia: Clinical-Histologic-Microbiologic Correlation and Review of the Literature

Agammaglobulinemia is the most common primary immunodeficiency, with an incidence of approximately 1 in 250,000 males in the United States. These patients are at risk for frequent recurrent infections, which may become fatal if untreated. Patients have increased susceptibility to encapsulated pyogenic bacteria. Haemophilus influenzae is second only to Streptococcus pneumoniae as the bacteria most frequently implicated in infections in these patients. We present a case involving an adolescent boy with X-linked agammaglobulinemia and H influenzae cervical adenopathy, confirmed twice by culture. We correlate the clinical, microbiologic, and histologic findings. Owing to the severity of infections in this population, surgical intervention is more common than in the immunocompetent population. This description may help the pathologist in considering a differential diagnosis when examining a diagnostic lymph node biopsy in these patients.

The potential utility of re-mining results of somatic mutation testing: KRAS status in lung adenocarcinoma

KRAS mutant non-small cell lung cancers (NSCLCs) vary in clinical outcome depending on which specific KRAS mutation is present. Shorter progression free survival has been associated with KRAS variants G12C and G12V. Cell lines with these variants depend to a greater extent on the RAS/RAF/MEK/ERK signaling pathway and become more susceptible to MEK inhibition. Because different KRAS mutations may lead to altered drug sensitivity, we aimed to determine specific KRAS mutation status in a NSCLC patient cohort at our institution. A total of 502 NSCLC samples were screened for somatic mutations using the 50 gene AmpliSeq™ Cancer Hotspot Panel v2 (CHPv2). However only samples positive for variants in the KRAS gene were included in this study. Variants identified in the KRAS genes were curated using publicly available databases. The overall mutation rate in the KRAS gene was 32.7% (164/502). The most common KRAS mutations were G12C (41%), G12V (19%), and G12D (14%) along with less frequent variants. After re-mining our sequencing data, we found that more than a half of our KRAS mutant NSCLC patients could potentially benefit from the addition of a MEK inhibitor such as selumetinib to standard chemotherapeutic agents. Due to mutated KRAS, these patients will likely fail traditional anti-EGFR therapies but be eligible for newer combination therapies.