The fine needle aspiration of translocation sarcomas.

INTRODUCTION: Soft tissue sarcomas comprise a heterogeneous group of clinically aggressive cancers that are often hard to classify on limited cytological samples. "Translocation sarcomas" (TS) are a diverse subset of such cancers, different from pleomorphic sarcomas, and characterised by unique single chromosomal translocations in each sarcoma subtype. Interestingly, despite their high-grade biological behaviour, TS have deceptively monotonous and bland cytomorphology, therefore creating diagnostic issues on limited samples. MATERIALS AND METHODS: A retrospective search was conducted of the cytopathology archives of The Johns Hopkins Hospital revealing 147 translocation sarcoma cases over a 25-year period. RESULTS: The common morphological denominators for most translocation sarcomas were: hypercellularity, cellular monotony, mostly discohesive and single cells, round-to-oval or short spindled cells and a lack of necrosis. The exceptions were an inflammatory myofibroblastic tumour, in which cellular monotony was not present owing to the prominence of lymphocytes and plasma cells, and low-grade fibromyxoid sarcoma, in which the specimens were generally hypocellular. Ancillary testing, especially immunoperoxidase staining, was often required for primary lesions. CONCLUSION: Distinct morphological clues and subsequent ancillary testing (particularly immunoperoxidase staining) provide an accurate diagnosis on cytological interpretation of both, primary and recurrent/metastatic lesions.

A G/C element mediates repression of the SM22alpha promoter within phenotypically modulated smooth muscle cells in experimental atherosclerosis.

A hallmark of smooth muscle cell (SMC) phenotypic switching in atherosclerotic lesions is suppression of SMC differentiation marker gene expression. Yet little is known regarding the molecular mechanisms that control this process. Here we show that transcription of the SMC differentiation marker gene SM22alpha is reduced in atherosclerotic lesions and identify a cis regulatory element in the SM22alpha promoter required for this process. Transgenic mice carrying the SM22alpha promoter-beta-galactosidase (beta-gal) reporter transgene were crossed to apolipoprotein E (ApoE)-/- mice. Cells of the fibrous cap, intima, and underlying media showed complete loss of beta-gal activity in advanced atherosclerotic lesions. Of major significance, mutation of a G/C-rich cis element in the SM22alpha promoter prevented the decrease in SM22alpha promoter-beta-gal reporter transgene expression, including in cells that compose the fibrous cap of the lesion and in medial cells in proximity to the lesion. To begin to assess mechanisms whereby the G/C repressor element mediates suppression of SM22alpha in atherosclerosis, we tested the hypothesis that effects may be mediated by platelet-derived growth factor (PDGF)-BB-induced increases in the G/C binding transcription factor Sp1. Consistent with this hypothesis, results of studies in cultured SMCs showed that: (1) PDGF-BB increased expression of Sp1; (2) PDGF-BB and Sp1 profoundly suppressed SM22alpha promoter activity as well as smooth muscle myosin heavy chain promoter activity through mechanisms that were at least partially dependent on the G/C cis element; and (3) a short interfering RNA to Sp1 increased basal expression and attenuated PDGF-BB induced suppression of SM22alpha. Together, these results support a model whereby a G/C repressor element within the SM22alpha promoter mediates transcriptional repression of this gene within phenotypically modulated SMCs in experimental atherosclerosis and provide indirect evidence implicating PDGF-BB and Sp1 as possible mediators of these effects.

L-type voltage-gated Ca2+ channels modulate expression of smooth muscle differentiation marker genes via a rho kinase/myocardin/SRF-dependent mechanism.

Vascular smooth muscle cell (SMC) contraction is mediated in part by calcium influx through L-type voltage-gated Ca2+ channels (VGCC) and activation of the RhoA/Rho kinase (ROK) signaling cascade. We tested the hypothesis that Ca2+ influx through VGCCs regulates SMC differentiation marker expression and that these effects are dependent on RhoA/ROK signaling. Depolarization-induced activation of VGCCs resulted in a nifedipine-sensitive increase in endogenous smooth muscle myosin heavy chain (SMMHC) and SM alpha-actin expression and CArG-dependent promoter activity, as well as c-fos promoter activity. The ROK inhibitor, Y-27632, prevented depolarization-induced increase in SMMHC/SM alpha-actin but had no effect on c-fos expression. Conversely, the Ca2+/calmodulin-dependent kinase inhibitor, KN93, prevented depolarization-induced increases in c-fos expression with no effect on SMMHC/SM alpha-actin. Depolarization increased expression of myocardin, a coactivator of SRF that mediates CArG-dependent transcription of SMC marker gene promoters containing paired CArG cis regulatory elements (SMMHC/SM alpha-actin). Both nifedipine and Y-27632 prevented the depolarization-induced increase in myocardin expression. Moreover, short interfering RNA (siRNA) specific for myocardin attenuated depolarization-induced SMMHC/SM alpha-actin transcription. Chromatin immunoprecipitation (ChIP) assays revealed that depolarization increased SRF enrichment of the CArG regions in the SMMHC, SM alpha-actin, and c-fos promoters in intact chromatin. Whereas Y-27632 decreased basal and depolarization-induced SRF enrichment in the SMMHC/SM alpha-actin promoter regions, it had no effect of SRF enrichment of c-fos. Taken together, these results provide evidence for a novel mechanism whereby Ca2+ influx via VGCCs stimulates expression of SMC differentiation marker genes through mechanisms that are dependent on ROK, myocardin, and increased binding of SRF to CArG cis regulatory elements.

Splenic cysts.

Benign non-parasitic cysts of the spleen are very uncommon, with a total of 651 cases having been described in the literature to date. Because of their uncommon nature, and the fact that their symtoms may be vague, a high index of suspicion is necessary if they are to be diagnosed. The therapy of choice is surgical excision by splenectomy and the accompanying cystectomy. The prognosis following such therapy is excellent.