Clonal chromosomal defects in the molecular pathogenesis of refractory hyperparathyroidism of uremia

Indirect X chromosome-inactivation analyses have demonstrated that most parathyroid glands from patients with uremic refractory secondary/tertiary hyperparathyroidism are monoclonal neoplasms. However, little is known regarding the specific acquired genetic abnormalities that must underlie such clonal expansion or the molecular pathogenetic features of this disorder, compared with primary parathyroid adenomas. To address these issues in a uniquely powerful manner, both comparative genomic hybridization (CGH) and genome-wide molecular allelotyping were performed with a large group of uremia-associated parathyroid tumors. As indicated by CGH, one or more chromosomal changes were present in 24% of the tumors, which is markedly different from the value for common sporadic adenomas (72%). Two recurrent abnormalities that had not been previously described for sporadic parathyroid adenomas were noted with CGH, i.e., gains on chromosomes 7 (9%) and 12 (11%). Losses on chromosome 11 occurred in only one of the 46 uremia-associated tumors (2%); the tumor also contained a somatic mutation of the remaining MEN1 allele (221del18). A total of 13% of tumors demonstrated recurrent allelic loss on 18q, with 18q21.1-q21.2 being defined as the putative tumor suppressor-containing region. In conclusion, the powerful combination of genome-wide molecular allelotyping and CGH has identified recurrent clonal DNA abnormalities that suggest the existence and locations of genes important in uremic hyperparathyroidism. In addition, genome-wide patterns of somatic DNA alterations, including disparate roles for MEN1 gene inactivation, indicate that markedly different molecular pathogenetic processes exist for clonal outgrowth in severe uremic hyperparathyroidism versus common parathyroid adenomas.     

日本国立大学高等医学教育考察

在日本国立神户大学医学部观察和体会日本国立重点大学的医学教育及其思考。     

Inhibition of tumor growth with antiangiogenic cancer vaccine using epitope peptides derived from human vascular endothelial growth factor receptor 1.

PURPOSE: Antiangiogenic therapy is now considered to be one of promising approaches to treat various types of cancer. In this study, we examined the possibility of developing antiangiogenic cancer vaccine targeting vascular endothelial growth factor receptor 1 (VEGFR1) overexpressed on endothelial cells of newly formed vessels in the tumor. EXPERIMENTAL DESIGN: Epitope-candidate peptides were predicted from the amino acid sequence of VEGFR1 based on their theoretical binding affinities to the corresponding HLAs. The A2/Kb transgenic mice, which express the alpha1 and alpha2 domains of human HLA-A*0201, were immunized with the epitope candidates to examine their effects. We also examined whether these peptides could induce human CTLs specific to the target cells in vitro. RESULTS: The CTL responses in A2/Kb transgenic mice were induced with vaccination using identified epitope peptides restricted to HLA-A*0201. Peptide-specific CTL clones were also induced in vitro with these identified epitope peptides from peripheral blood mononuclear cells donated by healthy volunteers with HLA-A*0201. We established CTL clones in vitro from human peripheral blood mononuclear cells with HLA-A*2402 as well. These CTL clones were shown to have potent cytotoxicities in a HLA class I-restricted manner not only against peptide-pulsed target cells but also against target cells endogenously expressing VEGFR1. Furthermore, immunization of A2/Kb transgenic mice with identified epitope peptides restricted to HLA-A*0201 was associated with significant suppression of tumor-induced angiogenesis and tumor growth without showing apparent adverse effects. CONCLUSIONS: These results strongly suggest that VEGFR1 is a promising target for antiangiogenic cancer vaccine and warrants further clinical development of this strategy.     

The relationship between spinal and appendicular bone mass modified by physical, historical, and lifestyle factors

Spinal, radial, and calcaneal bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and calcaneal bone mass measured by quantitative ultrasound densitometry (QUS) were compared in 83 healthy Japanese female volunteers. A significant and strong correlation was found within the same methods (r = 0.619 for lumbar spine and radius by DXA, r = 0.760 for lumbar spine and calcaneus by DXA, and r = 0.644 for calcaneus and radius by DXA), and within the same site (r = 0.758 for calcaneus by DXA and QUS). A lesser correlation was found when both the method and site were different (r = 0.521 for radius by DXA and calcaneus by QUS, and r = 0.583 for lumbar spine by DXA and calcaneus by QUS). Relations of spinal and appendicular bone mass were examined together with physical, historical, and lifestyle factors. Multiple correlation coefficients between bone mass at the lumbar spine and appendicular bone were 0.754 to 0.782, and all these increased after modification by physical, historical, and lifestyle factors in whichever appendicular bone. In the correlation between lumbar spine and radial BMD, past weight-bearing activity, age at menarche, family history of fractures, and body weight were chosen. Menstrual status, body weight, past weight-bearing activity, and present arm-using activity were chosen to determine the correlation between lumbar spine BMD and calcaneal bone mass by QUS. These results suggest that the incorporation of those factors improved the correlation between lumbar spine BMD and appendicular bone mass, especially in cases of lumbar spine BMD versus radial BMD or calcaneal bone mass by QUS. Received: Aug. 7, 1999 / Accepted: Oct. 29, 1999     

Increased expression of p34cdc2 and its kinase activity in human gastric and colonic carcinomas

We examined the expression of p34^cdc2 and its kinase activity in human gastric and colonic carcinoma cell lines and carcinoma tissues and studied its relation with a tumor-suppressor gene product, p53. All the gastric and colonic cancer cell lines expressed p34^cdC2 and showed its kinase activity at various levels. When the cells were arrested in mitotic metaphase by the use of nocodazole, p34^cdC2 kinase activity was induced and p53 was apparently phosphorylated. Of 12 gastric carcinoma cases, 11 (91.7%) showed higher p34^cdC2 kinase activity in tumor tissues than in corresponding non-neoplastic mucosa. The protein kinase activities in the individual cases were well correlated with the levels of p34^cdc2 protein expression. A good correlation was also found between the expression of p34^cdc2 and proliferating cell nuclear antigen (PCNA). Almost all the colonic carcinomas showed higher cdc2 kinase activity and increased p34 expression when compared with non-neoplastic mucosa. Interestingly, most of the gastric and colonic carcinomas having high cdc2 kinase activity expressed high levels of p53. These findings suggest that the increased p34^cdc2 kinase activity might cause the development and proliferation of gastric and colonic carcinomas, partly through abnormal p53 accumulation.     

Growth-regulatory mechanism of two human esophageal-cancer cell lines in protein-free conditions

We investigated the growth-regulatory mechanism of 2 esophageal squamous-cancer cell lines, TE2-NS and TE3-OS cells, both of which can grow stably in protein-free conditions in vitro. Protein-free conditioned media from TE2-NS and TE3-OS cells stimulated the growth of these cells. Exogenous epidermal growth factor (EGF), transforming growth factor-alpha (TGF-α), insulin-like growth factor (IGF)-I and -II enhanced cell proliferation by 2.2- to 3.8-fold in protein-free conditions, as compared with an untreated control. Receptor-binding assays showed that both TE2-NS and TE3-OS cells possessed a single class of high-affinity binding sites for IGF-I and 2 classes of binding sites for TGF-α, as confirmed on the cell membrane by immunochemistry. These results suggest that EGF, TGF-α and IGFs are candidates for the autocrine growth factor in cancer cells. The addition of inhibitory monoclonal antibodies against TGF-a and EGFR, but not those against either EGF or IGF-IR, significantly inhibited growth of the cells. Immunocytochemical staining and ELISA of the conditioned media both confirmed the production of TGF-α protein, but not EGF protein, in these cell lines. The data for a protein-free culture system strongly suggested that TGF-α, but not EGF or IGF, is biologically important as an autocrine growth factor in the growth of these cell lines in vitro.     

Expression of Amphiregulin, a Novel Gene of the Epidermal Growth Factor Family, in Human Gastric Carcinomas

The expression of mRNA for amphiregulin (AR), a novel gene of the epidermal growth factor family, was examined in 8 human gastric carcinoma cell lines and 32 gastric carcinoma tissues as well as corresponding normal mucosa. Of the 8 gastric carcinoma cell lines, 7 expressed 1.4 kb AR mRNA at various levels. The expression of AR mRNA by TMK-1 and MKN-28 cells was increased by treatment with epidermal growth factor or transforming growth factor α. In surgical cases, all the gastric carcinoma tissues and their adjacent normal mucosa expressed AR mRNA. Interestingly, 20 (62.5%) out of 32 tumors expressed AR mRNA at higher levels than their corresponding normal mucosas (tumor/normal ≥1.2). No obvious correlation was observed between the AR mRNA levels and the histological types or tumor staging of gastric carcinoma. Immunohistochemically, AR protein was localized to the cytoplasm and/or nucleus in tumor cells. These results suggest that AR produced by tumor cells may be involved in the pathogenesis and/or progression of human gastric carcinoma.     

Chromophobe renal cell carcinoma with osseous metaplasia: a case report

A 60-year-old Japanese male with a chromophobe cell carcinoma of his left kidney is reported. The tumor, 18 x 27 mm in size, was incidentally found by abdominal ultrasonography. Computed tomography and magnetic resonance imaging demonstrated a well-demarcated solid tumor arising from the lower pole of the left kidney. Histopathological examination of the surgically removed tumor revealed that it was composed of solid sheets of cancer cells having abundant and slightly eosinophilic reticular cytoplasm with accentuated cell membranes making up a plant cell-like appearance. Electron microscopic examination demonstrated numerous intracytoplasmic microvesicles. Although the tumor cells were positive for cytokeratin and epithelial membrane antigen, they did not show vimentin immunoreactivity. The unique histological finding of this tumor from other reported renal chromophobe carcinomas was that it had a peripheral fibrotic area with a focus of metaplastic ossification.     

Latest progress on chemotherapy for advanced gastric cancer

Although recent phase II studies have demonstrated high antitumor activity in the treatment of advanced gastric cancer, no significant survival benefit has been clearly demonstrated yet, when compared with 5-FU alone. More recently, a number of new agents including irinotecan and S-1 have demonstrated significant activity against gastric cancer as single agent or in combination with other chemotherapeutic agents. A phase III trial of 5-FU alone versus irinotecan plus cisplatin versus S-1 alone in advanced gastric cancer patients will be initiated in Japan Clinical Oncology Group (JCOG) within a few months. These new regimens have a potential becoming a new standard chemotherapy for the treatment of gastric cancer. The patients with peritoneal dissemination has usually not yet evaluated and explored from clinical study because of risk of toxicity and having no measurable disease. A next randomized phase III trial comparing 5-FU alone with sequential methotrexate and 5-fluorouracil in patients with peritoneal metastasis will be initiated in JCOG next year. The development of molecular biology has demonstrated the molecular mechanisms of chemoresistance or chemosensitivity, as well as a number of molecular targets against cancer cells. To date, many molecular targeted agents are being evaluated in various stages of clinical testing. These advances may provide a possibility of tailor made treatment.