Nicole A. Cipriani

Epigenetic Attenuation of Mitochondrial Superoxide Dismutase 2 in Pulmonary Arterial Hypertension A Basis for Excessive Cell Proliferation and a New Therapeutic Target

Background— Excessive proliferation and impaired apoptosis of pulmonary artery (PA) smooth muscle cells (PASMCs) contribute to vascular obstruction in patients and fawn-hooded rats (FHRs) with PA hypertension (PAH). Expression and activity of mitochondrial superoxide dismutase-2 (SOD2), the major generator of H2O2, is known to be reduced in PAH; however, the mechanism and therapeutic relevance of this are unknown. Methods and Results— SOD2 expression in PASMCs is decreased in PAH patients and FHRs with PAH. FHR PASMCs have higher proliferation and lower apoptosis rates than Sprague-Dawley rat PASMCs. Moreover, FHR PASMCs have hyperpolarized mitochondria, low H2O2 production, and reduced cytoplasmic and mitochondrial redox state. Administration of SOD2 small interfering RNA to normal PASMCs recapitulates the FHR PAH phenotype, hyperpolarizing mitochondria, decreasing H2O2, and inhibiting caspase activity. Conversely, SOD2 overexpression in FHR PASMCs or therapy with the SOD-mimetic metalloporphyrin Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP) reverses the hyperproliferative PAH phenotype. Importantly, SOD-mimetic therapy regresses PAH in vivo. Investigation of the SOD2 gene revealed no mutation, suggesting a possible epigenetic dysregulation. Genomic bisulfite sequencing demonstrates selective hypermethylation of a CpG island in an enhancer region of intron 2 and another in the promoter. Differential methylation occurs selectively in PAs versus aortic SMCs and is reversed by the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine, restoring both SOD2 expression and the ratio of proliferation to apoptosis. Expression of the enzymes that mediate gene methylation, DNA methyltransferases 1 and 3B, is upregulated in FHR lungs. Conclusions— Tissue-specific, epigenetic SOD2 deficiency initiates and sustains a heritable form of PAH by impairing redox signaling and creating a proliferative, apoptosis-resistant PASMC. SOD augmentation regresses experimental PAH. The discovery of an epigenetic component to PAH may offer new therapeutic targets.

MET as a target for treatment of chest tumors

The receptor tyrosine kinase MET has been studied of a large variety of human cancers, including lung and mesothelioma. The MET receptor and its ligand HGF (hepatocyte growth factor) play important roles in cell growth, survival and migration, and dysregulation of the HGF-MET pathway leads to oncogenic changes including tumor proliferation, angiogenesis and metastasis. In small cell lung cancer (SCLC), non-small cell lung cancer (NSCLC), and malignant pleural mesothelioma (MPM), MET is dysregulated via overexpression, constitutive activation, gene amplification, ligand-dependent activation, mutation or epigenetic mechanisms. New drugs targeted against MET and HGF are currently being investigated in vitro and in vivo, with promising results. These drugs function at a variety of steps within the HGF-MET pathway, including MET expression at the RNA or protein level, the ligand-receptor interaction, and tyrosine kinase function. This paper will review the structure, function, mechanisms of tumorigenesis, and potential for therapeutic inhibition of the MET receptor in lung cancer and mesothelioma.

Clinical and Pathologic Predictors of Lymph Node Metastasis and Recurrence in Papillary Thyroid Microcarcinoma

BACKGROUND The treatment for patients with papillary thyroid microcarcinoma (PTMC) is controversial because PTMC is often found incidentally and its prognosis is very good. Lymph node metastasis (LNM) is one of the main predictors of recurrence and survival. This retrospective study aimed to identify clinical and pathologic factors that increase the risk of metastasis or recurrence, in order to isolate clinically unfavorable PTMCs to help guide therapy. METHODS Clinical and pathologic data were collected from 273 patients diagnosed with PTMC at The University of Chicago Medical Center between 2000 and 2011. Data points included age, sex, race/ethnicity, tumor size, multifocality, thyroiditis, extrathyroidal extension (ETE), surgical margins, preoperative clinical suspicion of cancer, central/lateral lymph nodes removed and lymph nodes with metastatic carcinoma, treatment, local recurrence, distant recurrence, and survival. RESULTS Multivariate logistic regression showed that age <45 years (odds ratio [OR] = 3.565 [confidence interval (CI) 1.137-11.177]), multifocality (OR = 3.556 [CI 1.066-11.855]), and ETE (OR = 4.622 [CI = 1.068-20.011]) significantly increased the risk of central LNM (CLNM). However, sex, size of tumor, thyroiditis, positive margins, and clinical suspicion were not correlated with an increased risk for CLNM. Multivariate logistic regression showed that only ETE (OR = 16.066 [CI 1.850-139.488]) significantly increased the risk of lateral LNM. In the cohort of 202 patients with follow-up data, only six recurred. Median time to recurrence was approximately 12 months (range 3.5-120 months), and median follow-up was 42 months. No patient had distant metastasis, and no patients died. CONCLUSIONS PTMC is an indolent disease, but does pose a risk for LNM and local recurrence. More aggressive treatment or more frequent follow-up could be considered for patients with unfavorable features (age <45 years, multifocality, ETE), especially in the setting of involved lymph nodes at the time of surgical resection, as these patients may be at an increased risk for recurrence.

Lung cancer-a fractal viewpoint.

Fractals are mathematical constructs that show self-similarity over a range of scales and non-integer (fractal) dimensions. Owing to these properties, fractal geometry can be used to efficiently estimate the geometrical complexity, and the irregularity of shapes and patterns observed in lung tumour growth (over space or time), whereas the use of traditional Euclidean geometry in such calculations is more challenging. The application of fractal analysis in biomedical imaging and time series has shown considerable promise for measuring processes as varied as heart and respiratory rates, neuronal cell characterization, and vascular development. Despite the advantages of fractal mathematics and numerous studies demonstrating its applicability to lung cancer research, many researchers and clinicians remain unaware of its potential. Therefore, this Review aims to introduce the fundamental basis of fractals and to illustrate how analysis of fractal dimension (FD) and associated measurements, such as lacunarity (texture) can be performed. We describe the fractal nature of the lung and explain why this organ is particularly suited to fractal analysis. Studies that have used fractal analyses to quantify changes in nuclear and chromatin FD in primary and metastatic tumour cells, and clinical imaging studies that correlated changes in the FD of tumours on CT and/or PET images with tumour growth and treatment responses are reviewed. Moreover, the potential use of these techniques in the diagnosis and therapeutic management of lung cancer are discussed.

The Clinicopathologic Spectrum of Benign Mass Lesions of the Vocal Fold due to Vocal Abuse

Benign masses of the vocal fold related to phonotrauma are clinically classified into polyps, nodules, Reinke’s edema, and cysts. Despite the apparent distinctiveness of the clinical nomenclature, low inter- and intraobserver diagnostic agreement has been reported. Excepting cysts, which are epithelial lined, histologic examination of the remaining lesions has shown a variety of overlapping features insufficiently specific for the clinical diagnoses. This study reviews the clinicopathologic characteristics among these benign lesions of the vocal fold. A total of 78 nonneoplastic lesions of the vocal fold were reviewed by 2 pathologists for the presence of epithelial hyperplasia, basement membrane thickening, edema, vascular proliferation, and extracellular “amyloid-like” fibrin. In 46 cases with prebiopsy stroboscopic images, 2 otolaryngologists classified each lesion as polyp, nodule, Reinke’s edema, cyst, or other. They agreed in 43% (n = 20, 13 polyps, 5 nodules, 1 Reinke’s edema, 1 other) and disagreed in 57% (n = 26). There was no histologic feature that reliably distinguished among the lesions. In addition, reactive stromal cell atypia was present in 14 cases. Cysts were distinctive, as all were epithelial lined. The clinicopathologic classification of benign laryngeal lesions is neither clinically reproducible nor histologically unique. Treatment will continue to be individualized based on clinical judgment.

WHIM syndrome and oral squamous cell carcinoma.

WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is an autosomal dominant disease related to a mutation in the chemokine receptor CXCR4 resulting in altered immune function. An increased susceptibility in these patients to human papillomavirus (HPV) manifests as cutaneous warts and, in women, cervical dysplasia and squamous carcinoma. HPV-related squamous carcinoma in other sites has not been documented. We report the occurrence of HPV-related squamous cell carcinoma of the oral cavity in 2 siblings with WHIM syndrome, whose pedigree has previously been described.

NUT midline carcinoma of the larynx: an international series and review of the literature†

NUT midline carcinoma (NMC) is a rare undifferentiated and aggressive carcinoma that locates characteristically to the midline of the head and neck, and mediastinum. NMC is characterized by chromosomal rearrangements of the gene NUT, at 15q14. The BRD4 gene on 19q13 is the most common translocation partner forming a fusion oncogene, BRD4–NUT. By the end of 2014, the International NUT Midline Carcinoma Registry had 48 patients treated for NMC. Laryngeal NMC are exceedingly rare, and we report a case series of seven cases.

BRAF mutation in 'sarcomas': a possible method to detect de-differentiated melanomas.

BRAF is mutated in 50–60% of melanomas, but BRAF mutation in sarcomas has not been systematically evaluated. Some melanomas are spindled and may show no immunohistochemical evidence of melanocytic differentiation. Similarly, many sarcomas are undifferentiated, i.e. undifferentiated pleomorphic sarcomas (UPS). Diagnosing melanoma versus sarcoma in an undifferentiated spindle cell malignancy can be challenging. Our aim was to evaluate the prevalence of BRAF mutation in sarcomas and the use of BRAF mutational status in the diagnosis of spindle cell malignancies.

p16 immunohistochemistry in oropharyngeal squamous cell carcinoma: a comparison of antibody clones using patient outcomes and high-risk human papillomavirus RNA status

High-risk human papillomavirus (HPV)-related oropharyngeal squamous cell carcinomas have a more favorable prognosis than HPV-negative ones. p16 immunohistochemistry has been recommended as a prognostic test in clinical practice. Several p16 antibodies are available, and their performance has not been directly compared. We evaluated three commercially available p16 antibody clones (E6H4, JC8 and G175-405) utilizing 199 cases of oropharyngeal squamous cell carcinoma from a tissue microarray, read by three pathologists with three different cutoffs for positivity: any staining, >50% and >75%. Positive predictive values for high-risk HPV status by RNA in situ hybridization for the E6H4, JC8 and G175-405 clones were 98%, 100% and 99% at the 75% cutoff, but negative predictive values were much more variable at 86%, 69% and 56%, respectively. These improved using the 50% cutoff, becoming similar for all three antibodies. Intensity varied substantially, with 85% of E6H4, 72% of JC8 and 67% of G175-405 showing strong (3+) intensity. With Kaplan–Meier survival plots at the 75% cutoff, the E6H4 clone showed the largest differential in disease specific and overall survival between p16-positive and -negative results. Decreasing the cutoff to 50% increased correlation with HPV in situ hybridization and improved the survival differential for the JC8 and G175-405 clones without worsening of performance for the E6H4 clone. Interobserver agreement was also assessed by kappa scores and was highest for the E6H4 clone. Overall, these study results show modest but important performance differences between the three different p16 antibody clones, suggesting that the E6H4 clone performs best because of strongest staining intensity, greatest differential in outcomes between positive and negative results, lowest interobserver variability, and lowest background, nonspecific staining. The results also suggest that a 75% cutoff is very functional but that, in this patient population with high HPV incidence, 50% and any staining cutoffs may be more effective, particularly for the non-E6H4 clones.

Primitive myxoid mesenchymal tumor of infancy with rosettes: a new finding and literature review.

Primitive myxoid mesenchymal tumor of infancy (PMMTI) is a relatively recently described tumor arising in infants and demonstrating a unique histomorphology. We present an unusual case of PMMTI with rosettes, a hitherto undescribed finding in the reported cases. We also present the cytogenetic and ultrastructural findings of this tumor and review the literature. As awareness of PMMTI increases, additional clinical data and histopathologic findings will aid in the morphologic and behavioral characterization of this neoplasm.