Hiroyuki Kawami

Prognostic significance of co-expression of c-erbB-2 oncoprotein and epidermal growth factor receptor in breast cancer patients

The expression of c-erbB-2 oncoprotein and epidermal growth factor receptor (EGFR) was examined by immunocytochemical and radioreceptor assays in 115 patients with primary breast cancer. In 48 of 115 patients (42%), the assays were found to be positive for the expression of c-erbB-2 oncoprotein, and, in 44 of 115 (35%) patients, the assays were positive for the expression of EGFR. There was no correlation between the expression of c-erbB-2 oncoprotein and EGFR. Clinical survey demonstrated that both c-erbB-2 oncoprotein expression and EGFR expression have independent prognostic values. Furthermore, when patients were divided into three groups on the basis of the expression of both c-erbB-2 oncoprotein and EGFR, those who were found to be positive for the expression of both c-erbB-2 oncoprotein and EGFR showed a worse prognosis than other groups. These results suggest that the combination of the expression of both c-erbB-2 oncoprotein and EGFR may be important in selecting patients who have a poor prognosis.

Retrovirally transmitted gene therapy for gastric carcinoma using herpes simplex virus thymidine kinase gene

Background. Herpes simplex thymidine kinase (HTK) is known to phosphorylate ganciclovir (GCV). Phosphorylated GCV is incorporated into genomic DNA, which leads to inhibition of cell growth and cell death in the replicating cells. Recently, much attention has been drawn to the use of retrovirally mediated gene therapy using HTK as a new therapeutic approach for brain tumors. However, little is known about this phenomenon in gastrointestinal carcinomas.

Identification of an alternatively spliced RNA for the Ras suppressor RSU-1 in human gliomas

Previous studies demonstrated that the Ras suppressor, RSU-1, localizes to human chromosome 10p13, a region frequently deleted in high grade gliomas, and that RSU-1 expression inhibited the tumorigenesis of a glioblastoma cell line. We have now examined RNA from human glial tumors for RSU-1 expression by RT-PCR using primers for the 5′ and 3′ ends of the RSU-1 open reading frame. Analysis of the amplified RSU-1 cDNA demonstrated that in addition to the entire 858 bp RSU-1 open reading frame, a shorter 725 bp RSU-1 fragment was amplified as well. Sequencing of this product revealed that it encoded a RSU-1 cDNA product which was missing a single 133 bp internal exon. This exon-deleted product was found in 30% of the high grade gliomas studied and 2/3 oligodendrogliomas, but not in other CNS tumors, bladder or colon tumors or normal tissue. The exon-deleted RSU-1 product was infrequently detected in RNA from human tumor cell lines. Expression of an HA-tagged form of the deleted RSU-1 protein in transfected Cos 1 cells revealed that the protein was unstable, with a half life of less than 1 h, in contrast to the full length HA-tagged Rsu-1 protein which was stable for more than 4 h. These results suggest that the alternative splicing of the RSU-1 RNA to produce the exon-deleted form constitutes a mechanism for reduction or loss of functional Rsu-1. Because the expression of Rsu-1 can inhibit malignant growth of glioblastoma cells, the depletion of Rsu-1, via the production of the alternatively spliced form of RSU-1, may inhibit growth regulation in tumors.

Myxoma of the breast: Report of a case with unique histological and immunohistochemical appearances

A case of myxoma of the breast is reported. The patient, a 19 year old Japanese woman, showed a lump in the left breast which had enlarged gradually over 3 years. A tumor measuring 5 × 5 × 4.5 cm was located mainly in the mammary parenchyma, but partially involved the overlying subcutaneous tissue. Histologically the tumor was multinodular and each nodule consisted of an abundant myxoid substance with a few spindle or stellate mesenchymal cells. The presence of hyaluronic acid was observed in the myxoid area, and a few constituent cells showed Immunoreactivitiesfor S‐100 protein and α1‐antichymotrypsin. Electron microscopic studies revealed that some constituent cells looked like undifferentiated mesenchymal cells, while others showed a differentiation similar to fibroblast or histiocyte. These findings suggest that the constituent cells might derive from totlpotential primitive mesenchymal cells.

Modulation of CD4 Antigen Expression on the Lymphocyte Surface by Immunosuppressive Acidic Protein in Cancer Patients

The immunomodulatory effect of human immunosuppressive acidic protein (IAP) on lymphocyte surface antigens was investigated. IAP inhibited lymphocyte responses to phytohemagglutinin in a dose-dependent manner. By flow cytometry, using fluorescein-isothiocyanate-labelled antibodies, the mean fluorescence intensity on peripheral blood lymphocytes (PBLs) decreased for CD4, slightly decreased for CD3 but showed no change for the CD8 and T cell receptor alpha-beta antigens in the presence of IAP. This CD4 antigen modulation by IAP was observed in PBLs freshly isolated from patients with unresectable cancer but not in those isolated from patients with resectable tumor or from healthy volunteers. The modulation of the CD4 antigen by IAP on the lymphocyte surface was correlated with an increment of serum IAP levels in cancer patients. The CD4 modulation could be induced in PBLs from healthy volunteers by culturing them with IAP in vitro. It is suggested that IAP may play a role in cancer-related immunosuppression through the down-modulation of the CD4 antigen on the lymphocyte surface.

The expression and biological activity of IL-2 receptor on a human pancreas cancer cell line

To ascertain whether the tumor cells can regulate the host immune systems through the production of the cytokines or their receptors, we examined the expressions of tumor necrosis factorα (TNFα), tumor necrosis factor Β (TNFΒ), interleukin 2 (IL-2) and interleukin 2 receptor alpha chain (IL-2Rα) on the human cancer cell lines by Northern blot analysis. We used K562 (leukemia cell line), MCF-7 (breast cancer cell line), LS180, HT29 (colon cancer cell lines), SH101 (gastric cancer cell line) and PH101 (pancreas cancer cell line). Expressions of TNFα, TNFΒ and IL-2 mRNA were not detected in any of the tumor cell lines. However, 1.4 and 3.5 kilobases of the IL-2Rα mRNA were expressed in the PH101 cells, but not in the other five cell lines. Furthermore, IL-2Rα was detected on the cell surface of the PH101 cells by the flow-cytometric analysis with an anti-IL-2Rα monoclonal antibody. Interestingly, the soluble IL-2Rα (sIL-2Rα) was found in the conditioned media obtained from the PH101 cell culture with a sandwich enzyme immunoassay. Moreover, the sIL-2Rα secreted from the PH101 cells blocked the IL-2 dependent lymphocyte proliferation. These results indicate that the expression of IL-2Rα on PH101 might suppress the IL-2 induced lymphocyte proliferation.

A combination therapy with mitomycin c, etoposide, doxifluridine and medroxyprogesterone acetate as second line therapy for advanced breast cancer refractory to combination chemotherapy of cyclophosphamide, doxorubicin and 5 fluorouracil

Thirty-two patients with advanced breast cancer refractory to combination chemotherapy with cyclophosphamide (CPA), doxorubicin (ADR) and 5-fluorouracil (5-FU) (CAF) were treated with the combination of mitomycin C, etoposide, doxifluridine and medroxyprogesterone acetate as second line therapy. Observed responses included 6 patients (18.7%) with complete response (CR) and 7 (21.9%) with partial response (PR). Two (50%) out of 4 patients who had bone pain due to bone metastasis noted pain relief. CR or PR were obtained in 4 out of 12 patients who had not responded to the previous CAF therapy. While grade III myelosuppression was observed in 3 patients, other adverse effects were minimal. It is suggested that this combination therapy may be recommended for advanced breast cancer patients as a second therapy.

The augmentative effect of a protein-bound polysaccharide (PSK) on tumoricidal activity of the soluble factor produced by a streptococcal preparation (OK-432)-activated macrophages.

The enhancement of antitumor activities of the tumoricidal soluble factor (SF) from a streptococcal preparation (OK-432)-activated macrophages by the pretreatment with a protein-bound polysaccharide (PSK) was investigated in tumor-bearing mice.Two-step stimulations with OK-432 atin vivo priming andin vitro eliciting were required for the production of the tumoricidal SF by macrophages, and the tumoricidal activity of the SF apparently correlated with the uptake of OK-432 by macrophages at priming phase.Tumoricidal activity of the SF from OK-432-activated macrophages in proteose-peptone (P-P)-pretreated mice significantly decreased with the development of the tumor, whereas in PSK-pretreated mice did not. Pretreatment of tumor-bearing mice with PSK saved a decrease in the macrophages carrying Iak or asialo GM1 antigens and an increase in wheat germ agglutinin (WGA) receptors. Furthermore, the uptake of OK-432 by macrophages at priming phase was enhanced. The tumoricidal activity of the SF from OK-432-activated macrophages was augmented.Thus, PSK may restore the depressed functions of macrophages, and the combination therapy with PSK and OK-432 may be effective to enhance the production of tumoricidal SF in tumor-bearing mice.