Dermatomyositis: a clinicopathological study of 40 patients.

The histopathology of cutaneous lesions of dermatomyositis (DM) may be indistinguishable from acute cutaneous lesions of systemic lupus erythematosus (SLE). Misreported or incomplete clinical information may result in a clinicopathologic discrepancy and a delay in making a correct diagnosis of DM. The aim of this study was to systematically characterize the histopathologic findings of cutaneous lesions of DM and to determine if skin biopsy specimens of DM and SLE could be distinguished by light microscopic examination. Biopsies from 40 patients diagnosed with DM at the Wake Forest University School of Medicine from 1994 to 1999 were reviewed. The histological features by light microscopy were graded in a systematic fashion. We then assessed whether the cutaneous pathological changes of DM could be distinguished from those of SLE. Ten biopsy specimens each of DM and SLE (matched for anatomical site and lesion morphology) were randomized. Histological grading was performed in a blinded fashion, as was a histopathologic diagnosis (DM versus SLE). The most consistent histological findings of DM included increased dermal mucin, vacuolar alteration of the basal cell layer, and mild-to-moderate mononuclear cell inflammatory infiltrates. Our results show that the histological grading of SLE skin biopsies was nearly identical to that of DM. The correct histopathologic diagnosis of DM or SLE was made in 11 of the 20 skin biopsies without clinical information. Despite the limitations of our small sample size, these findings suggest that acute cutaneous lesions of SLE cannot be distinguished from DM. Clinicopathologic correlation is important for making a diagnosis of DM or SLE.

BRAF kinase in melanoma development and progression.

Cutaneous melanoma is increasing in incidence at one of the highest rates for any form of cancer in the USA, with a current lifetime incidence of 1 in 68. Although early-stage disease is often curable, the survival rate for advanced disease is low, with an average life expectancy of 6-10 months. Knowledge of the molecular alterations associated with melanoma development and progression is expected to lead to improved therapies and outcomes. Major progress in defining the molecular alterations associated with the evolution of melanoma came in 2002, through a systematic genome-wide assessment of cancer-associated pathways. Large-scale sequencing of growth-associated genes in a variety of cancers identified a high frequency (>60%) of activating mutations of the BRAF kinase gene in human melanomas. This discovery has prompted a large number of studies evaluating the biological significance of BRAF kinase mutations in the initiation and progression of melanoma, and their importance for the development of novel melanoma therapies. Here we review the most recent studies of BRAF kinase in the pathogenesis of melanoma and their implications for defining BRAF kinase as a therapeutic point of interest in melanoma.

Comprehensive expression profiling of tumor cell lines identifies molecular signatures of melanoma progression.

BACKGROUND: Gene expression profiling has revolutionized our ability to molecularly classify primary human tumors and significantly enhanced the development of novel tumor markers and therapies; however, progress in the diagnosis and treatment of melanoma over the past 3 decades has been limited, and there is currently no approved therapy that significantly extends lifespan in patients with advanced disease. Profiling studies of melanoma to date have been inconsistent due to the heterogeneous nature of this malignancy and the limited availability of informative tissue specimens from early stages of disease. METHODOLOGY/PRINCIPLE FINDINGS: In order to gain an improved understanding of the molecular basis of melanoma progression, we have compared gene expression profiles from a series of melanoma cell lines representing discrete stages of malignant progression that recapitulate critical characteristics of the primary lesions from which they were derived. Here we describe the unsupervised hierarchical clustering of profiling data from melanoma cell lines and melanocytes. This clustering identifies two distinctive molecular subclasses of melanoma segregating aggressive metastatic tumor cell lines from less-aggressive primary tumor cell lines. Further analysis of expression signatures associated with melanoma progression using functional annotations categorized these transcripts into three classes of genes: 1) Upregulation of activators of cell cycle progression, DNA replication and repair (CDCA2, NCAPH, NCAPG, NCAPG2, PBK, NUSAP1, BIRC5, ESCO2, HELLS, MELK, GINS1, GINS4, RAD54L, TYMS, and DHFR), 2) Loss of genes associated with cellular adhesion and melanocyte differentiation (CDH3, CDH1, c-KIT, PAX3, CITED1/MSG-1, TYR, MELANA, MC1R, and OCA2), 3) Upregulation of genes associated with resistance to apoptosis (BIRC5/survivin). While these broad classes of transcripts have previously been implicated in the progression of melanoma and other malignancies, the specific genes identified within each class of transcripts are novel. In addition, the transcription factor NF-KB was specifically identified as being a potential "master regulator" of melanoma invasion since NF-KB binding sites were identified as consistent consensus sequences within promoters of progression-associated genes. CONCLUSIONS/SIGNIFICANCE: We conclude that tumor cell lines are a valuable resource for the early identification of gene signatures associated with malignant progression in tumors with significant heterogeneity like melanoma. We further conclude that the development of novel data reduction algorithms for analysis of microarray studies is critical to allow for optimized mining of important, clinically-relevant datasets. It is expected that subsequent validation studies in primary human tissues using such an approach will lead to more rapid translation of such studies to the identification of novel tumor biomarkers and therapeutic targets.

Id1 expression is transcriptionally regulated in radial growth phase melanomas.

Id genes have been demonstrated to be upregulated in a wide variety of human malignancies and their expression has been correlated with disease prognosis; however, little is known about the mechanisms of Id gene activation in tumors. We have previously shown that the helix-loop-helix transcription factor, Id1, is highly expressed in primary human melanomas during the radial growth phase and that Id1 is a transcriptional repressor of the familial melanoma gene CDKN2A. Here we use a series of melanoma cell lines that recapitulate the phenotypic characteristics of melanomas at varying stages of malignant progression to evaluate the expression levels of Id1 in this model system and determine the mechanism of Id1 dysregulation in these tumor cells. We find elevated protein levels of Id1 to be present consistently in radial growth phase tumor cells in accordance with our primary tumor data. Id1 transcript levels were also found to be elevated in these radial growth phase melanoma cells without any appreciable evidence of gene amplification and Id1 promoter activity was found to correlate with Id expression levels. We therefore conclude that Id1 expression is primarily regulated at the transcriptional level in radial growth phase melanomas and expect that therapies that target Id1 gene expression may be useful in the treatment of Id-associated malignancies.