Takeshi Shiraishi

Clinical significance of molecular detection of carcinoma cells in lymph nodes and peripheral blood by reverse transcription-polymerase chain reaction in patients with gastrointestinal or breast carcinomas.

PURPOSE This study evaluates the clinical significance of detection of carcinoembryonic antigen (CEA) mRNA in the dissected lymph nodes and peripheral blood samples of patients with gastrointestinal or breast carcinomas. PATIENTS AND METHODS A total of 406 lymph nodes obtained from 65 patients were analyzed by both histologic and molecular examination of CEA-specific reverse transcriptase-polymerase chain reaction (RT-PCR). Peripheral blood samples from another 102 patients were also analyzed by CEA-specific RT-PCR. Patients were followed up prospectively for 24 +/- 12 months. RESULTS Of 406 lymph nodes, the positive detection rate increased from 20% by histologic examination to 60% by RT-PCR examination. The recurrence rate was 40% in 15 cases showing positive results in both examinations, 14% in 29 cases showing histologically negative but RT-PCR positive results, and none in 21 cases showing negative results in both examinations. The positive detection rate for CEA mRNA in peripheral blood samples increased with advancing stage of disease. With respect to 62 curatively operated cases, CEA mRNA was detected in 12 cases. Four of these 12 cases developed metastatic disease after surgery whereas none of 50 cases negative by RT-PCR developed metastasis. CONCLUSION It has been shown that RT-PCR is a powerful tool to detect CEA mRNA in the lymph nodes or the peripheral blood. This is potentially very useful to determine high-risk patients for metastasis. Serial analysis is warranted to assess the long-term significance of this method and its therapeutic and prognostic implications.

Analysis of MT1‐MMP and MMP2 expression in human gastric cancers

Membrane‐type 1 matrix metalloproteinase (MT1‐MMP) is a presumed activator of MMP2, which is one of the major proteinases in tumor cell invasion. In this study, we determined the clinico‐pathologic significance of MT1‐MMP expression in 68 human gastric carcinomas. The tumor‐normal ratio (T/N ratio) of MT1‐MMP expression was determined by reverse transcription‐polymerase chain reaction analysis. To visualize the localization of MT1‐MMP, an immunohistochemical study was performed. In addition, a gelatin zymography was done to examine the activation ratio of MMP2, and a correlation between MT1‐MMP expression and activation of MMP2 was studied. The expression of MT1‐MMP mRNA was higher in tumor tissue than in corresponding normal tissue in most cases. The mean value of the T/N ratio was 4.8. Twenty cases with T/N ≥ 4.8 showed significantly deeper invasion and higher frequency of lymph node metastasis than 48 cases with T/N < 4.8. MT1‐MMP expression was an independent factor influencing both tumor invasion of the gastric wall and lymph node metastasis. Although MT1‐MMP expression was not an independent prognostic factor, the patients with T/N ≥ 4.8 showed a significantly worse prognosis than those with T/N < 4.8. An immunohistochemical study demonstrated that MT1‐MMP expression was mainly recognized in the tumor cells. There was a significant correlation between MT1‐MMP expression and activation of MMP2. Our findings suggest that: 1) the expression of MT1‐MMP may influence prognosis via tumor invasion of the gastric wall and lymph node metastasis, and 2) MT1‐MMP activation of MMP2 may be clinically relevant in gastric carcinoma tumors. Int. J. Cancer 74:316‐321, 1997.

Sequence conservation at human and mouse orthologous common fragile regions, FRA3B/FHIT and Fra14A2/Fhit

It has been suggested that delayed DNA replication underlies fragility at common human fragile sites, but specific sequences responsible for expression of these inducible fragile sites have not been identified. One approach to identify such cis-acting sequences within the large nonexonic regions of fragile sites would be to identify conserved functional elements within orthologous fragile sites by interspecies sequence comparison. This study describes a comparison of orthologous fragile regions, the human FRA3B/FHIT and the murine Fra14A2/Fhit locus. We sequenced over 600 kbp of the mouse Fra14A2, covering the region orthologous to the fragile epicenter of FRA3B, and determined the Fhit deletion break points in a mouse kidney cancer cell line (RENCA). The murine Fra14A2 locus, like the human FRA3B, was characterized by a high AT content. Alignment of the two sequences showed that this fragile region was stable in evolution despite its susceptibility to mitotic recombination on inhibition of DNA replication. There were also several unusual highly conserved regions (HCRs). The positions of predicted matrix attachment regions (MARs), possibly related to replication origins, were not conserved. Of known fragile region landmarks, five cancer cell break points, one viral integration site, and one aphidicolin break cluster were located within or near HCRs. Thus, comparison of orthologous fragile regions has identified highly conserved sequences with possible functional roles in maintenance of fragility.

MAL gene expression in esophageal cancer suppresses motility, invasion and tumorigenicity and enhances apoptosis through the Fas pathway

We isolated the MAL (T-lymphocyte maturation associated protein) gene from differentially expressed products of esophageal epithelium relative to esophageal carcinoma tissues. The Mal protein has been demonstrated as being a component of the protein machinery for apical transport in epithelial polarized cells. In this study, we describe the reduced expression of MAL in all 39 cases of esophageal carcinoma tested and 60 other human carcinomas. MAL gene transcription was induced in three out of 13 esophageal carcinoma cell lines by treatment with the demethylating agent 5-aza-2′-deoxycytidine (DAC), and in nine additional cell lines by simultaneous treatment with trichostatin A, an inhibitor of deacetylation, and DAC. We established a stable MAL gene transfectant whose expression was regulated by subcutaneous doxycycline injection in nude mice. Tumor growth was suppressed in cells expressing TE3-MAL compared with TE3 parent cells or cells not expressing TE3-MAL with doxycycline injection (20 μg/body) (P<0.01). Additionally, the TE3-MAL transfectant cells exhibited decreased cellular motility, a G1/S transition block and increased levels of apoptosis, concomitant with increased expression of Fas receptor in vitro. The apoptotic staining in MAL-expressing tumors was confirmed by TUNEL assay. Therefore, we conclude that expression of MAL was frequently decreased or diminished in gastrointestinal tract cancers, and that Mal expression confers reduced tumorigenicity in vivo to tumor TE3 cells through the induction of apoptosis via the Fas signaling pathway.

Fragile site orthologs FHIT/FRA3B and Fhit/Fra14A2: Evolutionarily conserved but highly recombinogenic

Common fragile sites are regions that show elevated susceptibility to DNA damage, leading to alterations that can contribute to cancer development. FRA3B, located at chromosome region 3p14.2, is the most frequently expressed human common fragile site, and allelic losses at FRA3B have been observed in many types of cancer. The FHIT gene, encompassing the FRA3B region, is a tumor-suppressor gene. To identify the features of FHIT/FRA3B that might contribute to fragility, sequences of the human FHIT and the flanking PTPRG gene were compared with those of murine Fhit and Ptprg. Human and mouse orthologous genes, FHIT and Fhit, are more highly conserved through evolution than PTPRG/Ptprg and yet contain more sequence elements that are exquisitely sensitive to genomic rearrangements, such as high-flexibility regions and long interspersed nuclear element 1s, suggesting that common fragile sites serve a function. The conserved AT-rich high-flexibility regions are the most characteristic of common fragile sites.

Identification of cystatin B in human esophageal carcinoma, using differential displays in which the gene expression is related to lymph-node metastasis

Identification of the genes that are specifically expressed in either tumor or normal tissue is important for understanding cancer biology. Using differential displays, we obtained one gene which was specifically expressed in normal tissue but is only rarely expressed in carcinoma tissue of the human esophagus. The sequence of this gene was identical with cystatin B, known to be one of the cysteine‐proteinase inhibitors, mainly inhibiting cathepsin L. There is little information on the clinical significance of cystatin B expression in human esophageal carcinoma. We thus studied the mRNA expression of cystatin B in 45 tumor/normal pair specimens of the esophagus, using the semi‐quantitative reverse transcriptase polymerase chain reaction technique. The expression of cystatin B in tumor tissue was found to be markedly decreased compared with that of the corresponding normal tissue. The cases with a tumor/normal ratio of less than 0.5 showed high frequency of lymph‐node metastasis and more advanced clinical stage as compared with those whose tumor/normal ratio was equal to or more than 0.5. The decreased expression of cystatin B protein in carcinoma tissue was confirmed by immunohistochemical staining. Our study suggests that reduced expression of cystatin B in esophageal‐carcinoma tissue is associated with lymph‐node metastasis and may therefore prove to be a useful marker for predicting the biologic aggressiveness of human esophageal carcinoma. Int. J. Cancer (Pred. Oncol.) 79:175–178, 1998.© 1998 Wiley‐Liss, Inc.

RELAXATION OF INSULIN-LIKE GROWTH FACTOR 2 GENE IMPRINTING IN ESOPHAGEAL CANCER

Paternal allele‐specific expression is identified for the insulin‐like growth factor 2 (IGF2) gene. Relaxation or loss of IGF2 imprinting, however, has been reported in several neoplasms. We studied the expression of IGF2 mRNA in 35 squamous cancers of the esophagus and searched for the presence or absence of relaxation of IGF2 imprinting. In 28 (80%) cases, IGF2 mRNA was overexpressed in the tumor tissues (T) compared to the normal tissues (N). The patients whose tumor invaded the adventitia showed a higher T/N ratio than those whose tumor was restricted to the musculi propria layer. Heterozygosity was determined by using the Apa 1 polymorphism in exon 9. Thirteen of 35 cases showed heterozygosity. In these 13 cases, a similar analysis was performed on cDNA obtained by reverse transcriptase‐polymerase chain reaction. Consequently, 7 cases disclosed relaxation of IGF2 imprinting in the tumor tissue. The cases of esophageal cancer with relaxation of IGF2 imprinting showed a higher T/N ratio and deeper invasion than those without relaxation. The results suggest that overexpression of IGF2 mRNA plays an important role in esophageal cancer and, in certain cases, is associated with relaxation of IGF2 imprinting.

Microsatellite Instability Is Often Observed in Esophageal Carcinoma Patients with Allelic Loss in the FHIT/FRA3B Locus

We have previously reported a significant correlation between the progression of colorectal carcinoma and the loss of Fhit and Msh2 expression. This observation led us to investigate the effect of an allelic loss of the FHIT gene on esophageal cancer when coupled with a deficient mismatch repair system. In this study, 8 of 42 patients with esophageal cancer had microsatellite instability (MSI), and 29 cases demonstrated allelic loss (loss of heterozygosity or homozygous deletion) at the FHIT/FRA3B locus. All 8 MSI-positive cases showed allelic loss, while 13 of 34 MSI-negative cases retained both alleles, and a significant correlation was found between the incidence of MSI and allelic loss (p < 0.05). On the other hand, only 1 of the 8 MSI-positive patients exhibited neither Msh2 nor Fhit protein expression in both normal and carcinoma epithelial tissues, but neither a relationship between Msh2 expression and Fhit expression nor with the incidence of MSI was noted. This result indicated that the disruption of the mismatch repair system of Msh2 does not mainly lead to allelic loss of the FHIT/FRA3B locus as well as MSI in esophageal cancer. We concluded that MSI is significantly related to the allelic loss in the FHIT/FRA3B region, but Msh2 might be unrelated to the progression or oncogenic process in esophageal cancer.

Up-regulated pyrimidine nucleoside phosphorylase in breast carcinoma correlates with lymph node metastasis

BACKGROUND The clinical significance of pyrimidine nucleoside phosphorylase (PyNPase) activity in breast carcinomas has never been determined. MATERIALS AND METHODS In 41 cases of breast carcinoma, the enzyme activity of PyNPase was determined by the high performance liquid chromatography (HPLC) assay and its value was analyzed with clinicopathologic variables. The expression level of mRNA was examined by the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) assay and compared with the enzyme activity. RESULTS The higher activity of PyNPase was significantly correlated not only with the presence of vascular permeation (P = 0.02) but of lymph node metastasis (P = 0.02). The mRNA expression correlated well with the enzyme activity (r = 0.74, P < 0.01). A multivariate analysis disclosed the PyNPase factor to be associated with lymph node metastasis. In addition, 17 (41%) showed positive staining only in the tumor stromal cells and 18 (44%) cases showed positive staining in both the tumor stromal cells and the carcinoma cells by immunohistochemical study. CONCLUSIONS These findings suggest that PyNPase activity is a new marker predicting the malignant potential of breast carcinomas, especially with respect to lymph node metastasis, and that the RT-PCR assay is a more useful method than direct evaluation of PyNPase activity.

Analysis of ornithine decarboxylase messenger ribonucleic acid expression in colorectal carcinoma.

PURPOSE: Ornithine decarboxylase (ODC) is a rate-limiting enzyme for polyamine synthesis. An elevated protein level of ODC was observed in the tumors. There has been, however, little information reported so far on the expression of ODC messenger ribonucleic acid (mRNA) in clinical colorectal carcinomas.In vitrostudies disclosed that the transcriptions of the ODC gene is regulated by the c-mycgene. METHODS: The expression of ODC and c-mycmRNA in biopsy specimens obtained from both tumor tissue and the corresponding normal tissue was examined by the reverse transcriptase polymerase chain reaction method in 40 cases of colorectal carcinoma. RESULTS: The expression of ODC mRNA was observed in both tumor tissue and normal tissue. The tumor to normal ratio of ODC mRNA was higher in cases with deeply invasive tumors than in cases with shallow tumors, and it was also higher in Dukes B or C cases than in Dukes A cases. There was a significant correlation between the tumor to normal ratio of c-mycmRNA and that of ODC mRNA in each case. CONCLUSIONS: These findings suggested that 1) the study of the expression of ODC mRNA may be useful for preoperatively predicting more advanced disease of colon carcinoma, and 2) there was a significant correlation between expression of ODC and c-mycmRNA in the clinical samples, which was similar to the findings of a previousin vitrostudy.