Deregulation of the platelet-derived growth factor B-chain gene via fusion with collagen gene COL1A1 in dermatofibrosarcoma protuberans and giant-cell fibroblastoma

Dermatofibrosarcoma protuberans: Our experience of 59 cases

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue tumor with intermediate malignancy. It is initially located on the skin from where it is able to infiltrate the deep structures and has a tendency to recur locally following inadequate excision. A t(17;22)(q22;q13) chromosome trans-location is the main cytogenetic alteration responsible for the onset of DFSP. Treatment options include complete surgical excision by performing conventional surgery with wide margins (>3 cm) or Mohs micrographic surgery. A retrospective study was conducted in our Department of Plastic and Reconstructive Surgery and all data were collected from medical records of 59 DFSP patients within this department from 1999 to 2011. A total of 13 of 59 (22%) cases were treated with conventional excision; 3 (5%) cases resulted in tumor-free margins, 8 (14%) cases required surgical revision and 2 (3%) cases lead to recurrence. A total of 46 of 59 (78%) cases were treated with wide excision; 43 (73%) cases resulted in tumor-free margins, 3 (5%) cases required surgical revision and 0 (0%) cases lead to recurrence. In conclusion, the data collected reveal the controversy surrounding the adoption of general guidelines regarding safe margins. Further studies are required to investigate the possibility of obtaining genotypically altered margins from margins that may appear phenotypically healthy.

Pediatric sarcomas: translating molecular pathogenesis of disease to novel therapeutic possibilities

Pediatric sarcomas represent a diverse group of rare bone and soft tissue malignancies. Although the molecular mechanisms that propel the development of these cancers are not well understood, identification of tumor-specific translocations in many sarcomas has provided significant insight into their tumorigenesis. Each fusion protein resulting from these chromosomal translocations is thought to act as a driving force in the tumor, either as an aberrant transcription factor (TF), constitutively active growth factor, or ligand-independent receptor tyrosine kinase. Identification of transcriptional targets or signaling pathways modulated by these oncogenic fusions has led to the discovery of potential therapeutic targets. Some of these targets have shown considerable promise in preclinical models and are currently being tested in clinical trials. This review summarizes the molecular pathology of a subset of pediatric sarcomas with tumor-associated translocations and how increased understanding at the molecular level is being translated to novel therapeutic advances.

Fibrohistiocytic tumors and related neoplasms in children and adolescents

Fibrohistiocytic tumors (FHTs) in children and adolescents range from the benign fibrous histiocytoma, or dermatofibroma, to a variety of intermediate and malignant neoplasms, such as dermatofibrosarcoma protruberans and high-grade undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma). Those tumors as a group are comprised of fibroblasts, myofibroblasts, and histiocytes-dendritic cells with a variably prominent inflammatory infiltrate consisting of lymphocytes and eosinophils. Dendritic cells are also a major constituent of another group of neoplasms that include Langerhans cell histiocytosis, follicular and interdigitating cell sarcomas, and juvenile xanthogranuloma. These latter tumors are considered in this discussion for the sake of differential diagnosis and their possible histogenetic relationship to FHTs. Recent studies have suggested that the relationship between the fibroblast and histiocyte in the FHTs may reflect the intrinsic capacity to transdifferentiate from one to the other morphologic and functional state. The so-called "facultative fibroblast," as a cell with fibroblastic and histiocytic properties, was discussed in the context of the fibrous xanthoma 50 years ago. Possibly the entire histogenetic concept of FHTs should be reconsidered in light of current studies.

Key principles and clinical applications of "next-generation" DNA sequencing

Demand for fast, inexpensive, and accurate DNA sequencing data has led to the birth and dominance of a new generation of sequencing technologies. So-called "next-generation" sequencing technologies enable rapid generation of data by sequencing massive amounts of DNA in parallel using diverse methodologies which overcome the limitations of Sanger sequencing methods used to sequence the first human genome. Despite opening new frontiers of genomics research, the fundamental shift away from the Sanger sequencing that next-generation technologies has created has also left many unaware of the capabilities and applications of these new technologies, especially those in the clinical realm. Moreover, the brisk evolution of sequencing technologies has flooded the market with commercially available sequencing platforms, whose unique chemistries and diverse applications stand as another obstacle restricting the potential of next-generation sequencing. This review serves to provide a primer on next-generation sequencing technologies for clinical researchers and physician scientists. We provide an overview of the capabilities and clinical applications of DNA sequencing technologies to raise awareness among researchers about the power of these novel genomic tools. In addition, we discuss that key sequencing principles provide a comparison between existing and near-term technologies and outline key advantages and disadvantages between different sequencing platforms to help researchers choose an appropriate platform for their research interests.

Autocrine PDGF stimulation in malignancies

Platelet-derived growth factor (PDGF) isoforms are important mitogens for different types of mesenchymal cells, which have important functions during the embryonal development and in the adult during wound healing and tissue homeostasis. In tumors, PDGF isoforms are often over-expressed and contribute to the growth of both normal and malignant cells. This review focuses on tumors expressing PDGF isoforms together with their tyrosine kinase receptors, thus resulting in autocrine stimulation of growth and survival. Patients with such tumors could benefit from treatment with inhibitors of either PDGF or PDGF receptors.

Dermatofibrosarcoma Protuberans Male Breast: A Case report

Dermatofibrosarcoma protuberans is a relatively uncommon soft tissue tumor involving the dermal layer of skin with intermediate-to-low grade malignancy. Although metastasis rarely occurs, Dermatofibrosarcoma protuberans is a locally aggressive tumor with a high recurrence rate. We treated a 35-year-old male patient with Dermatofibrosarcoma protuberans left breast at Pakistan Air Force hospital Karachi. The reluctance on the patient's side unnecessarily delayed operative procedure. Allowing wide safety margins during resection, an extended resection was carried out. The patient was later subjected to radiotherapy.

Cytogenetics and molecular genetics of myxoid soft-tissue sarcomas

Myxoid soft-tissue sarcomas represent a heterogeneous group of mesenchymal tumors characterized by a predominantly myxoid matrix, including myxoid liposarcoma (MLS), low-grade fibromyxoid sarcoma (LGFMS), extraskeletal myxoid chondrosarcoma (EMC), myxofibrosarcoma, myxoinflammatory fibroblastic sarcoma (MIFS), and myxoid dermatofibrosarcoma protuberans (DFSP). Cytogenetic and molecular genetic analyses have shown that many of these sarcomas are characterized by recurrent chromosomal translocations resulting in highly specific fusion genes (e.g., FUS-DDIT3 in MLS, FUS-CREB3L2 in LGFMS, EWSR1-NR4A3 in EMC, and COL1A1-PDGFB in myxoid DFSP). Moreover, recent molecular analysis has demonstrated a translocation t(1; 10)(p22; q24) resulting in transcriptional upregulation of FGF8 and NPM3 in MIFS. Most recently, the presence of TGFBR3 and MGEA5 rearrangements has been identified in a subset of MIFS. These genetic alterations can be utilized as an adjunct in diagnostically challenging cases. In contrast, most myxofibrosarcomas have complex karyotypes lacking specific genetic alterations. This paper focuses on the cytogenetic and molecular genetic findings of myxoid soft-tissue sarcomas as well as their clinicopathological characteristics.

Changing pathology with changing drugs: skin cancer

Today skin cancer is mainly treated by surgical interventions. New findings concerning molecular biology and the signaling pathways in epithelial skin cancers such as basal cell carcinoma, squamous cell carcinoma or melanoma, and mesenchymal skin cancers such as angiosarcoma and dermatofibrosarcoma protuberans (DFSP) have identified new molecular targets for a systemic or local treatment approach. For DFSP there is an opportunity already today to reduce the intensity of surgical procedures by pretreatment with targeted therapy. This article highlights important aspects in several skin cancer types.

Treatment of advanced dermatofibrosarcoma protuberans with imatinib mesylate with or without surgical resection

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue sarcoma of the skin characterized by the presence of specific COL1A1-PDGFB fusion protein, which appears as a consequence of the t(17;22) (q22;q13) translocation.

OBJECTIVE

The aim of the study was to perform an analysis of patients with advanced DFSP treated with imatinib, with or without surgery, in clinical practice outside trials.

PATIENTS AND METHODS

We analysed the data of 15 patients (6 male, 9 female; median age 56 years) with locally advanced/initially inoperable and/or metastatic DFSP treated with imatinib 400-800 mg daily between 12/2004 and 06/2009. All diagnoses were ascertained cytogenetically (fluorescent in situ hybridization). Median follow-up time was 16 months (range: 4-81).

RESULTS

Metastases were present in six cases (two lungs, two soft tissue, two lymph nodes). Fibrosarcomatous transformation (FS-DFSP) was confirmed in seven patients (47%). A 2-year progression-free survival (PFS) rate was 60%, and a 2-year overall survival (OS) rate was 78% (median time for PFS/OS was not reached). The best overall responses were: 10 partial responses (67%, including 5 FS-DFSP-1 progressed during the follow-up), 2 stable diseases (13%) and 3 progressive diseases (20%). Seven patients (47%) underwent resection of residual disease and remained free of disease.

CONCLUSIONS

We have confirmed the profound anti-tumour effect of imatinib in DFSP harbouring t(17;22) with long-term responses. Imatinib therapy may in some cases lead to tumour resectability of lesser disfiguration.

Advances in molecular characterization and targeted therapy in dermatofibrosarcoma protuberans

The molecular pathogenesis of dermatofibrosarcoma protuberans (DFSP) involves distinctive rearrangement of chromosomes 17 and 22 leading to formation of the COL1A1-PDGFB fusion gene. The knowledge of molecular events underlying development of DFSP resulted in the implementation of targeted therapy with imatinib—a tyrosine kinase inhibitor (TKI), to the clinical practice. The striking efficacy of imatinib in advanced cases of DFSP has been demonstrated in a few clinical trials. Thus, imatinib is currently considered the gold standard in the treatment of inoperable and/or metastatic and/or recurrent cases of DFSP. Therapy with imatinib may potentially facilitate resection or decrease possible disfigurement related to radical surgical procedure. Following partial response on imatinib significant percentage of patients may be rendered free of the disease by surgery of the residual tumor.

Dermatofibrosarcoma protuberans (DFSP): predictors of recurrence and the use of systemic therapy

BACKGROUND

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue malignancy that typically presents with local invasion but rarely metastasizes. We examine clinicopathologic factors associated with disease-free survival (DFS) in patients with primary and recurrent DFSP and evaluate responses to multimodality therapy.

MATERIALS AND METHODS

Patients treated for DFSP were identified in a prospectively maintained database. Clinicopathologic factors associated with DFS were analyzed using univariate and multivariate analysis.

RESULTS

A total of 244 patients with DFSP were identified. Median follow-up was 50 months. A total of 14 patients had local recurrence (LR), and 2 patients had distant recurrence (DR), with a median time to recurrence of 35 months. At time of last follow-up, 70% and 47% of patients showed no evidence of disease (NED) in the primary (n = 197) and recurrent groups (n = 47), respectively. On univariate analysis, tumor location and depth were associated with DFS in the primary group, while margin status (R1 vs. R0) was associated with DFS in the LR group. On multivariate analysis, only depth (primary group) and margin status (LR group), remained significant. Also, 22 patients had therapy other than surgical resection: 14 radiotherapy, 4 tyrosine kinase inhibitor (TKI) only, 2 conventional chemotherapy only, and 2 chemotherapy plus TKI. Responses to other therapies were variable.

CONCLUSIONS

DFS after treatment for DFSP is strongly predicted by tumor depth in the primary setting and margin status in recurrent tumors. The treatment for DFSP in the primary or recurrent setting is excision with negative margins, resulting in low recurrence rates and infrequent metastatic spread. Multimodality treatment, especially TKI use, can be effective, but is not curative.

qPCR in gastrointestinal stromal tumors: Evaluation of reference genes and expression analysis of KIT and the alternative receptor tyrosine kinases FLT3, CSF1-R, PDGFRB, MET and AXL

Background

Gastrointestinal stromal tumors (GIST) represent the most common mesenchymal tumors of the gastrointestinal tract. About 85% carry an activating mutation in the KIT or PDGFRA gene. Approximately 10% of GIST are so-called wild type GIST (wt-GIST) without mutations in the hot spots. In the present study we evaluated appropriate reference genes for the expression analysis of formalin-fixed, paraffin-embedded and fresh frozen samples from gastrointestinal stromal tumors. We evaluated the gene expression of KIT as well as of the alternative receptor tyrosine kinase genes FLT3, CSF1-R, PDGFRB, AXL and MET by qPCR. wt-GIST were compared to samples with mutations in KIT exon 9 and 11 and PDGFRA exon 18 in order to evaluate whether overexpression of these alternative RTK might contribute to the pathogenesis of wt-GIST.

Results

Gene expression variability of the pooled cDNA samples is much lower than the single reverse transcription cDNA synthesis. By combining the lowest variability values of fixed and fresh tissue, the genes POLR2A, PPIA, RPLPO and TFRC were chosen for further analysis of the GIST samples. Overexpression of KIT compared to the corresponding normal tissue was detected in each GIST subgroup except in GIST with PDGFRA exon 18 mutation. Comparing our sample groups, no significant differences in the gene expression levels of FLT3, CSF1R and AXL were determined. An exception was the sample group with KIT exon 9 mutation. A significantly reduced expression of CSF1R, FLT3 and PDGFRB compared to the normal tissue was detected. GIST with mutations in KIT exon 9 and 11 and in PDGFRA exon 18 showed a significant PDGFRB downregulation.

Conclusions

As the variability of expression levels for the reference genes is very high comparing fresh frozen and formalin-fixed tissue there is a strong need for validation in each tissue type. None of the alternative receptor tyrosine kinases analyzed is associated with the pathogenesis of wild-type or mutated GIST. It remains to be clarified whether an autocrine or paracrine mechanism by overexpression of receptor tyrosine kinase ligands is responsible for the tumorigenesis of wt-GIST.

Dermatofibrosarcoma protuberans of the breast skin

A case of a 26-year-old woman with dermatofibrosarcoma protuberans of the breast skin is described. She had noticed a palpable mass with redness 15 years previously, but it had begun to grow rapidly with swelling and redness two months before presenting. Ultrasonography and biopsy demonstrated a possibility of sarcoma of the breast. Wide excision was performed to confirm the diagnosis. Histologically, the tumor was composed of a uniform population of fibroblasts in a distinct storiform pattern. CD34 immunostaining showed diffuse reactivity. Platelet-derived growth factor β break-apart fluorescence in situ hybridization analysis showed a split-signal pattern which supported the diagnosis of dermatofibrosarcoma protuberans in the skin of the breast. It is important to diagnose a soft tissue lesion accurately when it occurs in the breast.

Response of malignant scalp dermatofibrosarcoma to presurgical targeted growth factor inhibition

Dermatofibrosarcoma protuberans (DFSP) is an uncommon, locally aggressive, malignant cutaneous tumor that sparingly presents on the scalp. Dermatofibrosarcomas often result from the formation of a fusion oncogene on translocated or supernumerary ring chromosomes 17 and 22, causing the overexpression of PDGFRβ driven by the COL1A1 promoter. Because of uncertainty surrounding appropriate treatment of aggressive scalp DFSP, the authors performed an extensive review of the available data from a MEDLINE (Ovid) search to describe the clinical presentation and treatment options for this rare tumor. Their search identified 39 different cases, including the illustrative case presented in this study.

Adjuvant therapy for this malignant lesion is not universally established in the literature. In the present case, the authors successfully treated a locally invasive scalp DFSP with presurgical therapy that specifically inhibited the PDGFβ receptor. Imatinib significantly shrank the DFSP tumor mass, reduced hypervascularity, reduced metabolic activity on PET scanning, and permitted a safe gross-total resection. Although wide excision and Mohs micrographic surgery remain the standard surgical treatments for DFSP, the authors illustrate that presurgical chemotherapeutic treatment by imatinib provides a critical adjunct to traditional therapy.

The clinical relevance of molecular genetics in soft tissue sarcomas

Bone and soft tissue sarcomas are an infrequent and heterogeneous group of mesenchymal tumors including more than a hundred different entities attending to histologic patterns. Research into the molecular aspects of sarcomas has increased greatly in the last few years. This enormous amount of knowledge has allowed, for instance, to refine the classification of sarcomas, improve the diagnosis, and increase the number of therapeutical targets available, most of them under preclinical evaluation. However, other important key issues, such as sarcomagenesis and the cell of origin of sarcomas, remain unresolved. From a molecular point of view, these neoplasias are grouped into 2 main types: (a) sarcomas showing relatively simple karyotypes and translocations, which originate gene fusions (eg, EWS-FLI1 in Ewing sarcoma) or point mutations (eg, c-kit in the gastrointestinal tumors) and (b) sarcomas showing unspecific gene alterations, very complex karyotypes, and no translocations. The discovery of the early mechanisms involved in the genesis of sarcomas, the more relevant signaling pathways, and the development of genetically engineered mouse models could also provide a new individualized therapeutic strategy against these tumors. This review describes the clinical application of some of the molecular alterations found in sarcomas, some advances in the field of sarcomagenesis, and the development of animal models.

Increasing alternative promoter repertories is positively associated with differential expression and disease susceptibility

Background

Alternative Promoter (AP) usages have been shown to enable diversified transcriptional regulation of individual gene in a context-specific (e.g., pathway, cell lineage, tissue type, and development stage et. ac.) way. Aberrant uses of APs have been directly linked to mechanism of certain human diseases. However, whether or not there exists a general link between a gene's AP repertoire and its expression diversity is currently unknown. The general relation between a gene's AP repertoire and its disease susceptibility also remains largely unexplored.

Methodology/Principal Findings

Based on the differential expression ratio inferred from all human microarray data in NCBI GEO and the list of disease genes curated in public repositories, we systemically analyzed the general relation of AP repertoire with expression diversity and disease susceptibility. We found that genes with APs are more likely to be differentially expressed and/or disease associated than those with Single Promoter (SP), and genes with more APs are more likely differentially expressed and disease susceptible than those with less APs. Further analysis showed that genes with increased number of APs tend to have increased length in all aspects of gene structure including 3′ UTR, be associated with increased duplicability, and have increased connectivity in protein-protein interaction network.

Conclusions

Our genome-wide analysis provided evidences that increasing alternative promoter repertories is positively associated with differential expression and disease susceptibility.

The impact of advances in molecular genetic pathology on the classification, diagnosis and treatment of selected soft tissue tumors of the head and neck

Recent advances in molecular pathology have had a significant impact on the diagnosis, classification, and treatment of soft tissue tumors. The practical application of these discoveries promises to assist greatly in the evaluation and treatment of soft tissue neoplasms in the head and neck region-an area characterized by exceedingly complex anatomy that often restricts the ample sampling of lesions and complete surgical resection. This reviews details some ways in which molecular techniques have strengthened conventional diagnostic and management approaches to low-grade fibromyxoid sarcoma, angiomatoid (malignant) fibrous histiocytoma, and dermatofibrosarcoma protuberans, all of which may involve the head and neck region.

Aberrations of 6q13 mapped to the COL12A1 locus in chondromyxoid fibroma

Chondromyxoid fibroma, a rare benign bone tumor, may be mistaken for chondrosarcoma. Although cytogenetic studies of chondromyxoid fibroma are few, rearrangements of the long arm of chromosome 6, frequently expressed as an inv(6)(p25q13), are prominent. In this study, conventional cytogenetic analysis of 16 chondromyxoid fibroma samples from 14 patients revealed rearrangements of chromosome 6 in 10 of 11 clonally abnormal specimens. In addition to 6q13 rearrangements, recurrent 6p25 and 6q25 anomalies were detected. Notably, an identical t(6;9)(q25;q22) translocation was identified in two cases, suggesting that it represents a distinct translocation of chondromyxoid fibroma. In an effort to further define the aberrant 6q13 breakpoint and identify the molecular consequences, a fluorescence in situ hybridization (FISH)-based positional cloning strategy on chondromyxoid fibroma abnormal metaphase and interphase cells using a series of bacterial and plasmid artificial chromosome (BAC/PAC) probe combinations spanning a 6.1 Mb region was employed. The breakpoint on 6q13 was located within the COL12A1 gene, a collagen gene purportedly involved in another benign bone tumor, subungual exostosis. The findings of this study expand our knowledge of chromosomal alterations in chondromyxoid fibroma, identify COL12A1 as the likely gene candidate within the recurrent 6q13 breakpoint, and provide an alternative approach for detecting 6q13 anomalies in nondividing cells of chondromyxoid fibroma. The latter could potentially be utilized as an adjunct in diagnostically challenging cases.

[Long-term experience with multidisciplinary therapy of twenty-six patients with dermatofibrosarcoma protuberans]

Dermatofibrosarcoma protuberans is a low or moderate grade malignant, uncommon soft tissue tumor. The tumor is characterized by slow, but locally aggressive growth, low metastatic potential and high recurrence rate. Initial treatment is the radical surgical excision, using traditional wide excision or Mohs surgery. In case of positive surgical margin or local recurrence, radio-chemotherapy and recently imatinib mesylate is used as adjuvant therapy.

AIMS

Twenty-six patients treated multidisciplinary for dermatofibrosarcoma protuberans were followed up.

METHODS AND RESULTS

Mean age of the patients was 44.7 years; mean follow-up time was 60.57 months. In fifteen cases (57.7%) R0 resection was performed, while eleven patients (42,3%) received only R1 resection. An average of 1.87 resections was necessary in order to achieve R0 resection. Six patients (23%) received adjuvant radiotherapy and two patients (7.6%) adjuvant chemotherapy following the removal of the primary tumor. Sixteen patients had no local recurrence. Ongoing treatments were needed in the case of ten patients (38.4%) who developed local recurrence. One patient has deceased due to distant metastases. Using statistical methods we examined the effects indicated as prognostic factors in the literature on local recurrence, precisely, the effect of age above 50 years and surgical radicalism.

CONCLUSIONS

Dermatofibrosarcoma protuberans can be successfully treated with multidisciplinary therapy. A larger number of cases and randomized multicenter investigations are needed in order to reach more accurate conclusion.

Cancer genomics identifies regulatory gene networks associated with the transition from dysplasia to advanced lung adenocarcinomas induced by c-Raf-1

BACKGROUND

Lung cancer is a leading cause of cancer morbidity. To improve an understanding of molecular causes of disease a transgenic mouse model was investigated where targeted expression of the serine threonine kinase c-Raf to respiratory epithelium induced initially dysplasia and subsequently adenocarcinomas. This enables dissection of genetic events associated with precancerous and cancerous lesions.

METHODOLOGY/PRINCIPAL FINDINGS

By laser microdissection cancer cell populations were harvested and subjected to whole genome expression analyses. Overall 473 and 541 genes were significantly regulated, when cancer versus transgenic and non-transgenic cells were compared, giving rise to three distinct and one common regulatory gene network. At advanced stages of tumor growth predominately repression of gene expression was observed, but genes previously shown to be up-regulated in dysplasia were also up-regulated in solid tumors. Regulation of developmental programs as well as epithelial mesenchymal and mesenchymal endothelial transition was a hall mark of adenocarcinomas. Additionally, genes coding for cell adhesion, i.e. the integrins and the tight and gap junction proteins were repressed, whereas ligands for receptor tyrosine kinase such as epi- and amphiregulin were up-regulated. Notably, Vegfr- 2 and its ligand Vegfd, as well as Notch and Wnt signalling cascades were regulated as were glycosylases that influence cellular recognition. Other regulated signalling molecules included guanine exchange factors that play a role in an activation of the MAP kinases while several tumor suppressors i.e. Mcc, Hey1, Fat3, Armcx1 and Reck were significantly repressed. Finally, probable molecular switches forcing dysplastic cells into malignantly transformed cells could be identified.

CONCLUSIONS/SIGNIFICANCE

This study provides insight into molecular pertubations allowing dysplasia to progress further to adenocarcinoma induced by exaggerted c-Raf kinase activity.

Molecular genetics of sarcomas: applications to diagnoses and therapy

Sarcomas are mesenchymal cancers consisting of tumors with various clinical and pathological features. Some of them compel affected individuals to lose important musculoskeletal functions, and some of them are highly malignant and life-threatening. A great amount of genetic information for sarcomas has accumulated during the past two decades, contributing diagnoses and treatments. From the standpoint of molecular genetics, sarcomas are classified into two groups: those with defined genetic alterations and those with various genetic alterations. The genetic alterations in the first group include reciprocal translocations resulting in fusion oncoproteins and oncogenic mutations of defined genes such as those of the c-kit gene in gastrointestinal stromal tumors. The function of fusion proteins includes transcription regulator, signal transducer, chromatic remodeling factor, and growth factor, some of which are suitable targets for the molecular therapy. In tumors belonging to the second group, the number of which is far larger than those of the first group, considerable genetic heterogeneity was found even among tumors with same pathological diagnosis. The disruption of the RB and p53 pathways was frequently found, resulting in the dysregulation of cell cycle and the genomic instability. The application of molecular target therapy for tumors in this group requires novel strategies to overcome cross talk between different signal pathways. Recent evidence from in vitro and in vivo experiments has indicated that the cells of origin of sarcomas are tissue stem cells such as mesenchymal stem cells, and the application of stem cell biology holds the promise of novel treatment options.

PDGFB quantification is a useful tool in the diagnosis of dermatofibrosarcoma protuberans: a study of 10 cases

BACKGROUND

Genetic aberrations involving the platelet-derived growth factor-beta (PDGFB) gene and the collagen type 1 alpha1 (COL1A1) gene have been implicated in the pathogenesis of dermatofibrosarcoma protuberans (DFSP), a slow-growing and locally infiltrative dermal tumour.

AIM

To investigate the genetic rearrangements in 10 patients who presented with a clinical diagnosis of DFSP.

METHODS

Total RNA was obtained from frozen sections and sections embedded in paraffin wax, and used for direct sequencing of the cDNA produced from reverse transcription (RT) PCR. The expression of PDFGB mRNA in each of these cases was also examined.

RESULTS

Of the 10 samples examined, 9 had the COL1A1/PDGFB fusion transcript by DNA sequencing. The sequenced products showed that there was a fusion between the end of exons 6, 8, 29 (two cases), 38, 25 or 47 (three cases) and the start of exon 2 of the PDGFB gene. Quantitative RT-PCR identified all samples as having significantly higher expression of the PDGFB gene compared with normal skin or dermatofibroma.

CONCLUSIONS

Detection of the COL1A1/PDGFB fusion transcript may be important for the diagnosis of DFSP. Furthermore, relative PDGFB gene quantification by real-time PCR may also provide a good diagnostic tool when other methods fail to give conclusive results.

Rare skin cancer: a population-based cancer registry descriptive study of 151 consecutive cases diagnosed between 1980 and 2004

BACKGROUND

There are few epidemiological data available on rare skin cancer, including Merkel cell carcinoma, Paget's disease, adnexal carcinoma, and sarcoma. We conducted this study to investigate the epidemiology of rare skin cancer diagnosed in the department of Doubs from 1980 to 2004.

METHODS

Data were collected from a population-based cancer registry from 1980 to 2004. Diagnosis was based on the 3(rd) edition of the International Classification of Diseases for Oncology. The incidence rates were standardized on world population.

RESULTS

One hundred and fifty one patients were investigated (88 women and 63 men). Median age for the diagnosed disease was 63 years. The standardized incidence rate was 0.82/100 000 person-year (95% CI = 0.68-0.96) and increased from 0.25 in 1980-1984 to 1.50 in 2000-2004. Fifty nine cases (39%) were sarcomas, 35 (23%) adnexal carcinomas, 27 (18%) Merkel cell carcinoma and 27 (18%) Paget's disease. The standardized incidence rates were 0.37/100 000 (0.27-0.47) for sarcomas, 0.16 (0.10-0.22) for adnexal tumors, 0.13 (0.08-0.18) for Merkel cell carcinoma, and 0.15 (0.09-0.21) for Paget's disease.

CONCLUSIONS

Our results based on a population-based cancer registry showed an increase of the standardized incidence rate for all types of rare skin tumors. These results may be useful when considering the growing interest in rare diseases in identifying risk factors and planning scientific research programmes.

Selectivity and therapeutic inhibition of kinases: to be or not to be?

Protein kinases, which serve critical functions in signaling pathways in all cells, are popular therapeutic targets. At present, eight kinase inhibitors have been approved in the United States, each of which shows nanomolar potency. Although the initial goal was to generate inhibitors with a high degree of selectivity, recent experience has revealed that many of these approved compounds target more than one kinase. Surprisingly, this promiscuity is less problematic than one would have imagined; indeed, it opens new therapeutic opportunities. In this Perspective, we discuss the present status of Janus kinase inhibitors-a new class of immunosuppressive drugs-and the advantages and disadvantages of selectively inhibiting this class of kinase.

Genomic characteristics of soft tissue sarcomas

Studies on the molecular mechanisms behind soft tissue sarcoma development have disclosed that these malignancies are as genetically heterogeneous as they are clinically and morphologically diverse. Much of the genetic information on soft tissue sarcomas is still limited to the genomic level, as detected by chromosome banding analysis or comparative genomic hybridization. Based on the results of such studies, soft tissue sarcomas may be broadly dichotomized into one group, accounting for approximately 20% of the cases, characterized by specific balanced translocations, and one group typically showing massive chromosomal rearrangements leading to recurrent, but non-specific, structural and numerical rearrangements. As summarized in this review, the genomic characterization of soft tissue sarcomas has not only provided cell biologists with decisive information on the parts of the genome that may harbor genes that are essential for tumor development but also given the clinicians involved in the management of these patients a valuable diagnostic tool.

Imatinib in the treatment of solid tumours

The extraordinary success of imatinib in gastrointestinal stromal tumors (GIST) represents a model for molecularly targeted therapy for other solid tumors. Research is currently going to identify the molecular basis of mechanisms of action and drug resistance. In this article, we review recent advances in the clinical management of patients with GISTs treated with imatinib, but also of patients with dermatofibrosarcoma protuberans, chordoma, aggressive fibromatosis, and some other common solid tumors treated with this drug. We reviewed the knowledge of the molecular mechanisms that are basic to imatinib effects in these tumors.