Most CD56+ lymphomas display polymorphic and angiocentric/angiodestructive histologic features and are closely related to Epstein-Barr virus (EBV) infection. We report a 47-year-old Japanese man with CD56+ lymphoma that showed histologic features of lymphoblastic lymphoma with mediastinal and nasal involvement and an aggressive course. A sample specimen showed the histology of lymphoblastic lymphoma with a positive reaction for terminal deoxynucleotidyl transferase (TdT) but no angiocentric/angiodestructive features. Transmission electron microscopy revealed a few membrane-bound electron-dense granules in their cytoplasm. Immunohistochemically, lymphoma cells exhibited CD56+ cytoplasmic CD3 (cCD3)+ TdT+. A Southern blot analysis showed no integration of EBV and human T-lymphotrophic virus 1 (HTLV-1) and no rearrangement of the T-cell receptors or immunoglobulin heavy chain genes. This unusual lymphoblastic lymphoma exhibiting cCD3 + CD56 + TdT + TCR- is assumed as an immature or progenitor natural killer cell lineage.

The solitary fibrous tumor (SFT) is a rare tumor that most commonly arises in the pleura. Recent evidence has indicated that this tumor originates from mesenchymal, probably fibroblastic, cells and is not restricted to the pleura. However, its occurrence in the female genital tract is extremely rare. We report a case of primary SFT that originated from the vagina in a 34-year-old female. It was a pedunculated polypoid tumor and occurred at the site of scar tissue, caused by laceration during her last labor 7 years previously. Histologically, the tumor was predominantly composed of a random proliferation of spindle cells, intimately admixed with collagen. Immunohistochemically, the cells were strongly positive for CD34, vimentin and bcl-2, but were negative for S-100 protein, neuron-specific enolase, smooth muscle actin, desmin, CD68, cytokeratins and epithelial membrane antigen. To the best of our knowledge, this is the first reported case of a primary vaginal SFT in the English literature. Our report suggests to include SFT in the differential diagnosis of a spindle cell neoplasm originating from the vagina.

A new cell line (LC-1/sq) of human lung squamous-cell carcinoma was established from a surgically resected specimen of primary lung cancer. Upon continuous propagation in serum-free culture medium, it secreted trypsin inhibitors into the conditioned medium. The major fraction of the trypsin inhibitor (T1-1) was purified to apparent homogeneity by anion-exchange and gel-filtration high-performance liquid chromatography (HPLC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by transblotting to Immobilon. T1-1 effectively inhibited trypsin. Chymotrypsin, plasmin and kallikrein were inhibited to a lesser extent, but urokinase-type plasminogen activator, elastase, thrombin and papain were not inhibited. The activity of T1-1 was acid-stable and heat-resistant, and its molecular weight was 115 kDa by SDS-PAGE. It exhibited single NH2-terminal sequence, and its first 20 NH2-terminal amino-acid residues were identical with those of protease nexin-II (PN-II)/amyloid beta-protein precursor (APP). These characteristics of T1-1 suggest that the major trypsin inhibitor secreted by LC-1/sq is indistinguishable from PN-II/APP. LC-1/sq is the first lung squamous carcinoma cell line that secretes functionally active trypsin inhibitor, PN-II/APP, in vitro and is useful for studying its biological significance in malignant tumor.

We previously found that the enhanced activity to invade Matrigel upon stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA) was one of the major properties of a highly metastatic variant (L-10) of a human rectal adenocarcinoma cell line RCM-1. To clarify the mechanism of this enhancement, we examined the effect of TPA on 2 major biological factors involved in tumor cell invasion: cell motility and matrix-degrading metalloproteinase activity. The enhanced invasiveness was inhibited by protein-kinase-C inhibitors. TPA markedly enhanced both haptotactic response to type-IV collagen and motility on tissue-culture glass substrate of L-10 cells in a dose-response manner quite similar to that of TPA-enhanced invasion of Matrigel. On the other hand, TPA showed little enhancement of metalloproteinase production, which was assessed by gelatin- and casein-zymography, and of type-IV collagenolytic activity. Addition of TIMP (tissue inhibitors of metalloproteinase)-I inhibited TPA-enhanced invasion of Matrigel by only up to 13%. Thus, TPA treatment of L-10 cells enhanced invasion of Matrigel in association with augmentation of cell motility but did not enhance metalloproteinase activity.

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