Tall cell variant of papillary thyroid carcinoma: Its characteristic features demonstrated by fine‐needle aspiration cytology and immunohistochemical study

Tall cell variant (TCV) of papillary thyroid carcinoma is a rare tumor, which is usually associated with poor outcome, and pathologists often face the dilemma of proper diagnosis of TCV, not only by cytology but also histology. To allow surgeons to determine aggressiveness of the tumor before operation, it is important for pathologists to detect tall cell features correctly by fine‐needle aspiration cytology (FNAC). However, the current criteria and definition of TCV are still controversial and confounded by another problem, the differential diagnosis from poorly differentiated thyroid carcinoma (PDC). In this report, we describe two cases of TCV and present characteristic FNAC findings. The tumor cells had a peculiar shape, which included tall, columnar, and oxyphilic cytoplasm with “eccentric,” basally located nuclei. We propose new terms for these cells, such as “tail‐like cells” or “tadpole cells.” In the surgically‐resected specimens, both cases exhibited remarkable extrathyroidal invasion accompanying prominent vascular invasions. They showed high Ki‐67 (MIB‐1) labeling index by immunohistochemistry, which indicated a higher proliferation activity of TCV than conventional form of papillary thyroid carcinoma. Furthermore, we discuss in this report the problematic issue of differential diagnosis of TCV from PDC and oxyphilic papillary thyroid carcinoma. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.     

Mutations in the interferon sensitivity‐determining region of hepatitis C virus genotype 2a correlate with response to pegylated‐interferon‐alpha 2a monotherapy

The interferon sensitivity‐determining region (ISDR) is thought to be inhibited by the double‐stranded RNA‐dependent protein kinase (PKR). Several studies have reported a relationship between the ISDR and interferon (IFN) responsiveness. However, this relationship is controversial. The aim of this study was to investigate whether genomic heterogeneity of the ISDR among patients with hepatitis C virus (HCV) genotype 2a affects the response to pegylated‐IFN‐alpha 2a monotherapy. Eighty patients (47 men, 33 women; mean age: 54.2 ± 12.9 years) infected with HCV genotype 2a were evaluated. HCV viral loads were determined by real‐time PCR. The ISDR (amino acids 2193–2228) was examined by direct sequencing. Thirty‐one patients received subcutaneous injections of pegylated‐IFN‐alpha 2a (180 µg) once weekly for 24 weeks, and 35 patients received injections for 48 weeks. Fourteen patients withdrew from treatment. Of the remaining 66 patients, 51 (77.3%) showed a sustained virologic response. Factors related to sustained virologic response on multivariate analysis were rapid virologic response (negative HCV at 4 weeks; odds ratio: 0.033; 95% confidence interval (95% CI) 0.003–0.363; P = 0.0052) and the number of mutations in the ISDR (odds ratio: 0.025; 95% CI 0.001–0.476; P = 0.0141). There were no significant differences in other factors, including sex, age, aspartate aminotransferase, alanine aminotransferase, platelet count, duration of treatment, and HCV viral load. Rapid virologic response and the ISDR sequence variations are significantly associated with response to pegylated‐IFN‐alpha 2a monotherapy in Japanese patients with HCV genotype 2a. J. Med. Virol. 81:459–466, 2009. © 2009 Wiley‐Liss, Inc.     

Unique secretory dynamics of tissue plasminogen activator and its modulation by plasminogen activator inhibitor-1 in vascular endothelial cells

We analyzed the secretory dynamics of tissue plasminogen activator (tPA) in EA.hy926 cells, an established vascular endothelial cell (VEC) line producing GFP-tagged tPA, using total internal reflection-fluorescence (TIR-F) microscopy. tPA-GFP was detected in small granules in EA.hy926 cells, the distribution of which was indistinguishable from intrinsically expressed tPA. Its secretory dynamics were unique, with prolonged (> 5 minutes) retention of the tPA-GFP on the cell surface, appearing as fluorescent spots in two-thirds of the exocytosis events. The rapid disappearance (mostly by 250 ms) of a domain-deletion mutant of tPA-GFP possessing only the signal peptide and catalytic domain indicates that the amino-terminal heavy chain of tPA-GFP is essential for binding to the membrane surface. The addition of PAI-1 dose-dependently facilitated the dissociation of membrane-retained tPA and increased the amounts of tPA-PAI-1 high-molecular-weight complexes in the medium. Accordingly, suppression of PAI-1 synthesis in EA.hy926 cells by siRNA prolonged the dissociation of tPA-GFP, whereas a catalytically inactive mutant of tPA-GFP not forming complexes with PAI-1 remained on the membrane even after PAI-1 treatment. Our results provide new insights into the relationship between exocytosed, membrane-retained tPA and PAI-1, which would modulate cell surface-associated fibrinolytic potential.     

Simultaneous two-color spectral fluorescence lymphangiography with near infrared quantum dots to map two lymphatic flows from the breast and the upper extremity

Due to their small size and poor access, the lymphatic function has been difficult to study in vivo. Especially difficult is the mapping of lymphatic drainage from two basins into the same node. Quantum dots can be used to perform multicolor images with high fluorescent intensity and are of a nano-size size suitable for lymphatic imaging via direct interstitial injection. Here we show simultaneous two-color in vivo wavelength-resolved spectral fluorescence lymphangiography using two near infrared quantum dots with different emission spectra, which allow non-invasive and simultaneous visualization of two separate lymphatic flows draining the breast and the upper extremity and variations in the drainage patterns and the water sheds within the axillary node. Two-color spectral fluorescence lymphangiography can provide insight into mechanisms of drainage from different lymphatic basins that may lead to sentinel lymph nodes detection of the breast cancer as well as prevention of complications such as lymphedema of the arm. Yukihiro Hama and Yoshinori Koyama are contributed equally to this work.     

Nuclear cyclin B1 in human breast carcinoma as a potent prognostic factor

Cyclin B1 is translocated to the nucleus from the cytoplasm, and plays an essential role in cell proliferation through promotion of mitosis. Although overexpression of cyclin B1 was previously reported in breast carcinomas, the biological significance of the intracellular localization of cyclin B1 remains unclear. Therefore, in this study, we examined cyclin B1 immunoreactivity in 109 breast carcinomas, according to the intracellular localization, that is, nucleus, cytoplasm or total (nucleus or cytoplasm). Total cyclin B1 was detected in carcinoma cells in 42% of breast carcinomas examined, whereas nuclear and cytoplasmic cyclin B1 were positive in 17 and 35% of the cases, respectively. Total or cytoplasmic cyclin B1 were positively associated with histological grade, mitosis, Ki-67, p53, c-myc or 14-3-3sigma, and inversely correlated with estrogen or progesterone receptor. Nuclear cyclin B1 was significantly associated with tumor size, lymph node metastasis, histological grade, mitosis, Ki-67 or polo-like kinase 1. Only nuclear cyclin B1 was significantly associated with adverse clinical outcome of the patients, and multivariate analyses of disease-free and overall survival demonstrated nuclear cyclin B1 as the independent marker. A similar tendency was detected in the patients receiving adjuvant therapy after surgery. These results suggest that an onocogenic role of overexpressed cyclin B1 is mainly mediated in nuclei of breast carcinoma cells, and the nuclear translocation is regulated by polo-like kinase 1 and 14-3-3sigma. Nuclear cyclin B1-positive breast carcinoma is resistant to adjuvant therapy, and nuclear cyclin B1 immunoreactivity is a potent prognostic factor in breast carcinoma patients.     

Overexpression of caveolin-1 in a human melanoma cell line results in dispersion of ganglioside GD3 from lipid rafts and alteration of leading edges, leading to attenuation of malignant properties

Caveolin-1 is a component of lipid rafts, and is considered to be a tumor suppressor molecule. However, the mechanisms by which caveolin-1 functions in cancer cells are not well understood. We generated caveolin-1 transfectant cells (Cav-1(+) cells) using a human melanoma cell line (SK-MEL-28) and investigated the effects of caveolin-1 overexpression on the GD3-mediated malignant properties of melanomas. Cav-1(+) cells had decreased cell growth and motility, and reduced phosphorylation levels of p130Cas and paxillin relative to controls. In floatation analysis, although GD3 was mainly localized in glycolipid-enriched microdomain (GEM)/rafts in control cells, it was dispersed from GEM/rafts in Cav-1(+) cells. Correspondingly, GD3 in Cav-1(+) cells stained uniformly throughout the membrane, whereas control cells showed partial staining of the membrane, probably at the leading edge. p130Cas and paxillin were stained in the leading edges and colocalized with GD3 in the control cells. In contrast, these molecules were diffusely stained and no definite leading edges were detected in Cav-1(+) cells. These results suggest that caveolin-1 regulates GD3-mediated malignant signals by altering GD3 distribution and leading edge formation. These results reveal one of the mechanisms by which caveolin-1 curtails the malignant properties of tumor cells.     

Separate elements are required for ligand-dependent and -independent internalization of metastatic potentiator CXCR4

The C-terminal cytoplasmic domain of the metastatic potentiator CXCR4 regulates its function and spatiotemporal expression. However, little is known about the mechanism underlying constitutive internalization of CXCR4 compared to internalization mediated by its ligand, stromal cell-derived factor-1 alpha (SDF-1alpha)/CXCL12. We established a system to analyze the role of the CXCR4 cytoplasmic tail in steady-state internalization using the NP2 cell line, which lacks endogenous CXCR4 and SDF-1alpha. Deleting more than six amino acids from the C-terminus dramatically reduced constitutive internalization of CXCR4. Alanine substitution mutations revealed that three of those amino acids Ser(344) Glu(345) Ser(346) are essential for efficient steady-state internalization of CXCR4. Mutating Glu(345) to Asp did not disrupt internalization, suggesting that the steady-state internalization motif is S(E/D)S. When responses to SDF-1alpha were tested, cells expressing CXCR4 mutants lacking the C-terminal 10, 14, 22, 31 or 44 amino acids did not show downregulation of cell surface CXCR4 or the cell migration induced by SDF-1alpha. Interestingly, however, we identified two mutants, one with E344A mutation and the other lacking the C-terminal 17 amino acids, that were defective in constitutive internalization but competent in ligand-promoted internalization and cell migration. These data demonstrate that ligand-dependent and -independent internalization is genetically separable and that, between amino acids 336 and 342, there is a negative regulatory element for ligand-promoted internalization. Potential involvement of this novel motif in cancer metastasis and other CXCR4-associated disorders such as warts, hypogammaglobulinemia, infections and myelokathexis (WHIM) syndrome is discussed.     

Unusual case of progressive systemic sclerosis with onset in early childhood and following infectious mononucleosis

A rare case of infantile progressive systemic sclerosis is reported. A Japanese girl suffered from infectious mononucleosis at the age of 1 year 3 months, and 5 months later she developed edema and sclerosis of the skin. She has been followed up for 4 years and now has grotesque features, with contractures of hands and feet due to advanced systemic sclerosis. The relationship between infectious mononucleosis and progressive systemic sclerosis is discussed.