Expression of phospho-mTOR kinase is abundant in colorectal cancer and associated with left-sided tumor localization.

PURPOSE: To investigate the significance of mammalian target of rapamycin (mTOR) in colorectal cancers. mTOR has recently been suggested as a prognostic biomarker and therapeutic target in an array of human cancers. FINDINGS: phospho-mTOR (p-mTOR) expression was analyzed by immunohistochemistry (IHC) on a tissue microarray containing 1800 colorectal cancers (CRC). Clinical follow-up data were available from all cancer patients. Positive p-mTOR immunostaining was seen in 83.5% of 1640 interpretable CRC and was considered weak in 862 (52.5%) and strong in 508 cases (31.0%). Matching clinico-pathological parameters were available in 1580 cases. p-mTOR staining was more frequent in tubular adenocarcinomas than in the less common histological subtypes (mucinous, medullary, signet cell; P=0.0163) and significantly linked to carcinomas of the left-sided colon and rectum as compared to right-sided CRC (P=0.0066). There was no significant association between p-mTOR expression and patients' gender, tumor stage, tumor grade or nodal status. In a survival analysis, p-mTOR IHC status of all CRC was unrelated to patient survival (P=0.702). In a multivariate analysis including pT, pN, tumor grade, tumor localization and p-mTOR expression, only pT, pN (both P<0.0001) and grade (P=0.0001) showed prognostic impact, but not tumor localization (P=0.9472) or p-mTOR expression (P=0.8879). CONCLUSION: Our observations indicate that p-mTOR overexpression is abundant in CRC and linked to left-sided tumor localization. The high frequency and overexpression of p-mTOR is providing further rationale for targeting this pathway therapeutically in CRC patients. However, a prognostic role of p-mTOR overexpression in CRC could not be confirmed.

Correlation between chemosensitivity to anticancer drugs and telomerase reverse transcriptase mRNA expression in gastric cancer.

BACKGROUND: The determination of sensitive chemotherapy drugs for gastric cancer (GC) is one of the greatest challenges of adjuvant therapy. Here we evaluated the chemosensitivity of GC to anticancer drugs and the telomerase reverse transcriptase (hTERT) mRNA expression, and investigated the relationship of them. METHODS: The GC cells which were collected from 68 patients with primary GC were primary cultured. The chemosensitivity of GC cells to anticancer drugs was evaluated successfully using the MTT assay for 60 cases of GC cells, and the hTERT mRNA expression was examined in 60 cases of GC tissues and corresponding normal gastric mucosa and 6 cases of chronic superficial gastritis mucosa by in situ hybridization. RESULTS: Taxol, cisplatin and 5-fluorouracil were in general more effective than adriamycin and mitomycin for GC cells, and the chemosensitivity to anticancer drugs was associated with tumor histological types and a worse tumor grade. Compared to normal gastric mucosa tissues, hTERT mRNA expression was significantly increased in GC (P<0.05), which was related with a worse differentiation and drug-resistance to 5-fluorouracil or adriamycin in GC. CONCLUSIONS: These data demonstrate for the first time that examinations of hTERT mRNA expression as an important factor could be used to select the chemotherapeutic drugs for GC patients. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1793217009875483.

Expression of pyruvate dehydrogenase kinase-1 in gastric cancer as a potential therapeutic target.

In contrast to mitochondria in healthy cells, which utilize oxidative phosphorylation, malignant cells undergo elevated glycolysis for energy production using glucose. The objectives of this study were to evaluate whether the expression of various molecules, including pyruvate dehydrogenase kinase-1 (PDK-1), is involved in the altered glucose metabolism associated with gastric cancer prognosis and to assess the role of a therapeutic agent in targeting glucose metabolism in gastric cancer. Immunohistochemistry was performed on gastric cancer tissues obtained from 152 patients who underwent curative resection to assess the expression of hypoxia-inducible factor-1α (HIF-1α), glucose transporter-1 (GLUT-1), hexokinase-2 (HK-2) and PDK-1. In an in vitro analysis, the lactate production and glucose uptake levels, cellular viability and 5-fluorouracil (5-FU) responses were evaluated before and after treatment with dichloroacetate (DCA), a PDK-1 inhibitor, in the MKN45 and AGS gastric cancer cell lines and in the non-cancerous HEK293 cell line. GLUT-1 and PDK-1 expression was significantly associated with tumor progression, although only PDK-1 expression was an independent prognostic factor for patients who received 5-FU adjuvant treatment. There was no significant difference in cell viability between the HEK293 and gastric cancer cell lines following DCA treatment. However, DCA treatment reduced lactate production and increased responsiveness to 5-FU in MKN45 cells, which expressed high levels of PDK-1 in comparison to the other cell lines. Thus, PDK-1 may serve as a biomarker of poor prognosis in patients with gastric cancer. In addition, PDK-1 inhibitors such as DCA may be considered an additional treatment option for patients with PDK-1-expressing gastric cancers.

Overexpression of the M2 isoform of pyruvate kinase is an adverse prognostic factor for signet ring cell gastric cancer.

AIM: To investigate M2 isoform of pyruvate kinase (PKM2) expression in gastric cancers and evaluate its potential as a prognostic biomarker and an anticancer target. METHODS: All tissue samples were derived from gastric cancer patients underwent curative gastrectomy as a primary treatment. Clinical and pathological information were obtained from the medical records. Gene expression microarray data from 60 cancer and 19 non-cancer gastric tissues were analyzed to evaluate the expression level of PKM2 mRNA. Tissue microarrays were constructed from 368 gastric cancer patients. Immunohistochemistry was used to measure PKM2 expression and PKM2 positivity of cancer was determined by proportion of PKM2-positive tumor cells and staining intensity. Association between PKM2 expression and the clinicopathological factors was evaluated and the correlation between PKM2 and cancer prognosis was evaluated. RESULTS: PKM2 mRNA levels were increased more than 2-fold in primary gastric cancers compared to adjacent normal tissues from the same patients (log transformed expression level: 7.6 ± 0.65 vs 6.3 ± 0.51, P < 0.001). Moreover, differentiated type cancers had significantly higher PKM2 mRNA compared to undifferentiated type cancers (log transformed expression level: 7.8 ± 0.70 vs 6.7 ± 0.71, P < 0.001). PKM2 protein was mainly localized in the cytoplasm of primary cancer cells and detected in 144 of 368 (39.1%) human gastric cancer cases. PKM2 expression was not related with stage (P = 0.811), but strongly correlated with gastric cancer differentiation (P < 0.001). Differentiated type cancers expressed more PKM2 protein than did the undifferentiated ones. Well differentiated adenocarcinoma showed 63.6% PKM2-positive cells; in contrast, signet-ring cell cancers showed only 17.7% PKM2-positive cells. Importantly, PKM2 expression was correlated with shorter overall survival (P < 0.05) independent of stage only in signet-ring cell cancers. CONCLUSION: PKM2 expression might be an adverse prognostic factor for signet-ring cell carcinomas. Its function and potential as a prognostic marker should be further verified in gastric cancer.

Histologic and cytomorphologic features of ALK-rearranged lung adenocarcinomas.

Chromosomal rearrangements leading to constitutive activation of anaplastic lymphoma receptor tyrosine kinase (ALK) define a category of lung adenocarcinomas that may be amenable to targeted therapy with the ALK inhibitor crizotinib. Defining distinctive features of ALK-rearranged (ALK+) lung adenocarcinomas may help identify cases that merit molecular testing. However, data describing the morphologic features of ALK+ lung adenocarcinomas are conflicting and are primarily based on analysis of resected primary lung tumors. It is unclear whether the findings from prior studies are applicable to metastatic lung tumors or to small biopsy/cytology specimens. To address these issues, we examined resection, excision, small biopsy, and cytology cell block specimens from 104 ALK+ and 215 ALK- lung adenocarcinomas from primary and metastatic sites. All cases were evaluated for ALK rearrangements by fluorescence in situ hybridization. The predominant histologic subtypes and distinctive cytomorphologic features were assessed in each case. Primary ALK+ lung adenocarcinomas showed a significant association with solid, micropapillary, and papillary-predominant histologic patterns and tumor cells with a signet ring or hepatoid cytomorphology. Among metastatic lung tumors and small biopsy/cytology specimens, the only distinguishing morphologic feature of ALK+ tumors was the presence of signet ring cells. Based on these results, we developed a morphology-based scoring system for predicting ALK rearrangements in lung adenocarcinomas. The scoring system predicted ALK rearrangements in a new cohort of 78 lung adenocarcinomas (29 ALK+ and 49 ALK-) with a sensitivity of 88% and a specificity of 45%. In conclusion, ALK+ lung adenocarcinomas have distinctive morphologic features, with signet ring cells showing a significant association with ALK rearrangements irrespective of tumor site (primary vs metastatic) or specimen type. However, morphologic screening alone will not detect a minority of ALK+ lung adenocarcinomas, and the routine use of ancillary studies may be warranted to identify all patients who may benefit from crizotinib treatment.

Differing expression of metalloprotease and of adhesion molecules in signet-ring cell and intestinal colorectal carcinoma.

BACKGROUND: Pure signet-ring cell colorectal carcinoma (SRCC) is an infrequent and highly malignant histological variant of colorectal cancer (CRC), while it is present as a histological component in colorectal carcinomas more frequently. MATERIALS AND METHODS: The aim of this work was to widen the knowledge of the biological factors involved in the pathogenesis and aggressiveness of SRCC by the identification and evaluation of possible molecular abnormalities. By means of immunohistochemistry the expression of the proteolytic degradation enzyme matrix metalloprotease (MMP)-1, that is a collagenase specifically degrading collagens I, II, III and of the adhesion proteins E-cadherin, beta-catenin and fibronectin which are usually involved in the carcinogenesis of conventional colorectal tumours was investigated. RESULTS: SRCCs showed a significantly greater MMP-1 expression compared to the ordinary intestinal colorectal cancer (ICRC) and a significantly reduced E-cadherin, beta-catenin and fibronectin expression. CONCLUSION: The biological aggressiveness and strong metastatic behaviour of SRCC could be due to high MMP-1 and low expression of the adhesion molecules.

SIRT1 histone deacetylase expression is associated with microsatellite instability and CpG island methylator phenotype in colorectal cancer.

The class III histone deacetylase SIRT1 (sir2) is important in epigenetic gene silencing. Inhibition of SIRT1 reactivates silenced genes, suggesting a possible therapeutic approach of targeted reversal of aberrantly silenced genes. In addition, SIRT1 may be involved in the well-known link between obesity, cellular energy balance and cancer. However, a comprehensive study of SIRT1 using human cancer tissue with clinical outcome data is currently lacking, and its prognostic significance is uncertain. Using the database of 485 colorectal cancers in two independent prospective cohort studies, we detected SIRT1 overexpression in 180 (37%) tumors by immunohistochemistry. We examined its relationship to the CpG island methylator phenotype (CIMP), related molecular events, clinical features including body mass index, and patient survival. We quantified DNA methylation in eight CIMP-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1) and eight other CpG islands (CHFR, HIC1, IGFBP3, MGMT, MINT1, MINT31, p14, and WRN) by MethyLight. SIRT1 overexpression was associated with CIMP-high (> or =6 of 8 methylated CIMP-specific promoters, P=0.002) and microsatellite instability (MSI)-high phenotype (P<0.0001). In both univariate and multivariate analyses, SIRT1 overexpression was significantly associated with the CIMP-high MSI-high phenotype (multivariate odds ratio, 3.20; 95% confidence interval, 1.35-7.59; P=0.008). In addition, mucinous component (P=0.01), high tumor grade (P=0.02), and fatty acid synthase overexpression (P=0.04) were significantly associated with SIRT positivity in multivariate analysis. SIRT1 was not significantly related with age, sex, tumor location, stage, signet ring cells, cyclooxygenase-2 (COX-2), LINE-1 hypomethylation, KRAS, BRAF, BMI, PIK3CA, HDAC, p53, beta-catenin, COX-2, or patient prognosis. In conclusion, SIRT1 expression is associated with CIMP-high MSI-high colon cancer, suggesting involvement of SIRT1 in gene silencing in this unique tumor subtype.

Evidence for cancer-associated expression of NADPH oxidase 1 (Nox1)-based oxidase system in the human stomach.

Helicobacter pylori infection has been suggested to stimulate expression of the NADPH oxidase 1 (Nox1)-based oxidase system in guinea pig gastric epithelium, whereas Nox1 mRNA expression has not yet been documented in the human stomach. PCR of human stomach cDNA libraries showed that Nox1 and Nox organizer 1 (NOXO1) messages were absent from normal stomachs, while they were specifically coexpressed in intestinal- and diffuse-type adenocarcinomas including signet-ring cell carcinoma. Immunohistochemistry showed that Nox1 and NOXO1 proteins were absent from chronic atrophic gastritis (15 cases), adenomas (4 cases), or surrounding tissues of adenocarcinomas (45 cases). In contrast, Nox1 and its partner proteins were expressed in intestinal-type adenocarcinomas (19/21 cases), diffuse-type adenocarcinomas (15/15 cases), and signet-ring cell carcinomas (9/9 cases). Confocal microscopy revealed that Nox1, NOXO1, Nox activator 1, and p22(phox) were predominantly associated with Golgi apparatus in these cancer cells, while diffuse-type adenocarcinomas also contained cancer cells having Nox1 and its partner proteins in their nuclei. Nox1-expressing cancer cells exhibited both gastric and intestinal phenotypes, as assessed by expression of mucin core polypeptides. Thus, the Nox1-base oxidase may be a potential marker of neoplastic transformation and play an important role in oxygen radical- and inflammation-dependent carcinogenesis in the human stomach.

The close relationship between heparanase and cyclooxygenase-2 expressions in signet-ring cell carcinoma of the stomach.

Signet-ring cell carcinoma (SRC) of the stomach exhibits diffuse growth and invasion without forming ducts. Destruction of the surrounding basal membrane and angiogenesis appear to be required for SRC to exhibit marked invasion and growth. We recently reported that heparanase (HPA) and cyclooxygenase-2 (COX-2) were strongly correlated with microvessel density, and that COX-2 expression is up-regulated by HPA in esophageal cancer. In this study, we examined the relationship between HPA expression and that of COX-2 in SRC of the stomach. We examined HPA and COX-2 expression in 3 cell lines derived from SRC of the stomach and in 50 SRC lesions of stomach by immunohistochemistry (IHC), in situ hybridization, and reverse transcriptase-polymerase chain reaction (RT-PCR). We also examined the relationships among HPA expression, COX-2 expression, and the clinicopathologic features of SRC, mean age, sex, invasion depth, regional lymph node metastasis, lymphatic invasion, and venous blood vessel invasion. Of the 3 cell lines, 2 exhibited both HPA and COX-2 mRNA expression on RT-PCR. Of the 3 cell lines, 1 exhibited only HPA mRNA expression on RT-PCR. Heparanase expression was confirmed in 23 (46%) of 50 tumor samples by IHC. COX-2 expression was confirmed in 25 (50%) of the 50 tumor samples by IHC. In situ hybridization revealed messenger RNA expression in the same area as in that revealed by IHC. A close correlation was noted between HPA and COX-2 expressions (P < .0001). The present study thus elucidated the biologic features of SRC of the stomach related to growth and angiogenesis.

Diverse cellular localizations of secretory phospholipase A2 enzymes in several human tissues.

The secretory phospholipase A2 (sPLA2) family in mammals contains more than 10 enzymes. In this study, we examined by immunohistochemistry the localization of six sPLA2s (IIA, IID, IIE, IIF, V and X) in human heart, kidney, liver and stomach. In normal hearts, sPLA2-IIA was detected in coronary vascular smooth muscle cells (VSMC) and sPLA2-V in cardiomyocytes beneath the endocardium. In infarcted hearts, expression of these two enzymes was markedly increased in damaged cardiomyocytes, and expression of sPLA2-IID and-IIE, which was undetectable in normal hearts, was elevated in damaged cardiomyocytes and VSMC, respectively. In infarcted kidneys, sPLA2-IIA and-V were markedly induced in the uriniferous tubular epithelium. In livers affected by viral hepatitis, sPLA2-IIA and-V were expressed in hepatocytes with fatty degeneration. In the gastric glands exhibiting intestinal metaplasia, sPLA2-IIA was localized in the glandular base, sPLA2-IID and-V in the glandular body epithelium, sPLA2-IIE and-IIF in goblet cells in the foveolar epithelium, and sPLA2-X in both glandular body epithelial cells and foveolar epithelial goblet cells. In the gastric submucosal tissues, sPLA2-IIA and-IIE were located in VSMC and sPLA2-V was in the interstitial fibroblasts. In addition, sPLA2-IIA,-IIE,-IIF and-X were highly expressed in gastric signet ring cell carcinoma. Thus, individual sPLA2s exhibit unique cellular localizations in each tissue, suggesting their distinct roles in pathophysiology.

Advanced gastric cancer with peritoneal dissemination successfully treated with paclitaxel and doxifluridine: a case report.

A 50-year-old female presenting with severe ascites and anemia and diagnosed with advanced gastric cancer was admitted to our hospital. Endoscopic examination revealed an edematous lesion with redness and a giant fold in the stomach with poor expansion. The histological examination of biopsy specimens from the edematous lesion revealed signet-ring-cell carcinoma. Computed tomography demonstrated a thickening of the gastric wall, severe ascites, and peritoneal dissemination in the Douglas pouch. Paclitaxel (70mg/m2) was administered to the patient on days 1, 8, and 15, with doxifluridine (533mg/m2) for five days per week, on a 28-day cycle. By completion of the first course of treatment, the ascites had disappeared, the tumor in the Douglas pouch had shrunk, and the thickening of the gastric wall had lessened. In addition, the fold in the stomach appeared by endoscopic examination to have resumed its normal thickness, no malignant cells were detected in a biopsy, and the thymidine phosphorylase activity in the tumor tissue was two-fold greater than that before chemotherapy. After three treatment courses, the number of apoptotic cells had apparently increased compared with the prechemotherapy number. The only adverse drug reactions that were observed were grade 2 alopecia and grade 1 myalgia. After thirteen courses of chemotherapy over the past one year, both primary and metastatic lesions seem to be regressing. This case study suggests that paclitaxel plus doxifluridine therapy is effective and well-tolerated in non-resectable gastric cancer patients.

Clinical relevance of thymidylate synthase expression in the signet ring cell histotype component of colorectal carcinoma.

Thymidylate Synthase (TS) is the key enzyme for DNA synthesis pathways and is inhibited by 5-fluorouracil (5FU). The aim of this work was to study TS expression and the proliferation rate in the different histological types of colorectal carcinoma (CRC). 50 patients with CRC were included in this study and evaluated immunohistochemically using the monoclonal antibodies, TS106 and Ki67. 20 tumours were of the intestinal type, 15 cases were signet ring cell carcinoma (SRCCs) and 15 cases were "mixed-type", with at least two different histological components. Intestinal and mucinous histotypes were positive for TS and Ki67, while "signet ring cell" samples were negative or showed only weak and focal positivity for both the TS and Ki67 antibodies. Our results show that signet ring cells (that are also often present in intestinal and mucinous carcinomas), are in the post-mitotic phase of the cell cycle and show a low proliferation index and TS expression. As TS is the key enzyme for DNA synthesis pathways and is inhibited by 5-fluorouracil (5FU), we can hypothesise that TS expression levels in the different histotypes of CRC could affect the potential responsiveness of these tumours to fluoropyrimidine chemotherapy, with a low efficacy being expected in signet ring cell areas.

Increased expression of matrix metalloproteinase-7 in invasive early gastric cancer.

BACKGROUND: Matrix metalloproteinase-7 (MMP-7), a proteolytic enzyme, is suspected to play an important role in the progression of various cancers. To clarify the clinical importance of MMP-7, we retrospectively analyzed MMP-7 expression in gastric epithelial tumors. METHODS: We tested 201 lesions (from 172 patients) of surgically or endoscopically resected gastric epithelial tumors (gastric cancer, 158 lesions; gastric adenoma, 32 lesions; hyperplastic polyp, 11 lesions). MMP-7 expression was immunohistochemically examined. Sections with immunostaining signals in more than 30% of tumor cells were judged to show positive expression. RESULTS: MMP-7 was expressed in 33.3% (67/201) of all lesions. MMP-7-positive tumors were significantly more frequent in diffuse-type adenocarcinomas (62.2%; 28/45) compared with intestinal-type lesions (31.9%; 36/113; P < 0.001). Cancers invading the submucosa or deeper (60.5%; 46/76) were showed positivity significantly more frequently than mucosal cancers (22.0%; 18/82; P < 0.001). MMP-7-positive lesions increased with the progression of gastric epithelial tumors, including adenomas, mucosal cancers, and cancers invading the submucosal layer or deeper (P < 0.001). MMP-7 expression occurred significantly more often in lymphatic invasion-positive cancers (65.1%; 41/63) than in lymphatic invasion-negative cancers (24.2%; 23/95; P < 0.001). CONCLUSIONS: The MMP-7-positive rate increased with the progression of gastric epithelial tumors, such as adenoma, mucosal cancer, and cancer invading the submucosal layer or deeper. MMP-7 was significantly associated with aggressive pathological phenotypes of cancer. The detection of the MMP-7 protein may be useful in pretherapeutic diagnosis.

Induction of PIG3 and NOXA through acetylation of p53 at 320 and 373 lysine residues as a mechanism for apoptotic cell death by histone deacetylase inhibitors.

Two controversial issues regarding p53 are whether it is involved in apoptosis induction of tumor cells by a histone deacetylase (HDAC) inhibitor and, given that p53 is indeed involved, which genes of acetylated p53 targets are responsible for giving rise to apoptotic death. We, in the present study, first confirmed that some substantial extent of apoptotic cell death was seen when p53-deficient cells (KATO-III) were transfected with wild-type p53 and treated with sodium butyrate (SB) or trichostatin A. By Western blotting, using specific antibodies, we then demonstrated that residues 320, 373, and 382 lysines of p53 were acetylated in KATO-III cells transfected with wild-type p53 (KATO-III/p53) treated with a HDAC inhibitor. However, as revealed by terminal deoxynucleotidyl transferase-mediated nick end labeling staining, only those KATO-III cells transfected with K320R p53 or K373R p53 became insensitive to the HDAC inhibitor, suggesting that these two residues of p53 may be essential for HDAC inhibitor-induced apoptosis, whereas others such as K382R p53 may not. Furthermore, reverse transcription-PCR demonstrated that among various p53-related proapoptotic genes, expression of PIG3 and NOXA were clearly enhanced by SB treatment in KATO-III/p53 cells but not in KATO-III/K320R or KATO-III/K373R cells. Finally, we revealed that apoptosis could be evoked by SB even in cells where p53 mutations occur at residues other than 320 lysine or 373 lysine (TMK-1 and HSC-39 cells) and that this apoptosis was significantly, although not totally, suppressed by the anti-p53 antisense. It was, therefore, concluded that acetylation of the p53 molecule at residues 320 and 373, giving rise to up-regulation of PIG3 and NOXA, is one of the mechanisms for induction of apoptosis by HDAC inhibitors in cancer cells.

Activation of ErbB3-PI3-kinase pathway is correlated with malignant phenotypes of adenocarcinomas.

Signet-ring cell carcinomas are malignant dedifferentiated carcinomas, which are frequently found in the stomach. We previously demonstrated that a 200 kDa protein is often constitutively phosphorylated on tyrosine and bound to phosphatidylinositol 3-kinase (PI3-kinase) in signet-ring cell carcinoma cells. In this study, we purified the 200 kDa protein from an extract of NUGC-4 cells, a cell line of signet-ring cell carcinoma, and identified it as ErbB3. ErbB3 was found to be phosphorylated selectively in dedifferentiated adenocarcinoma cell lines among various gastric cancer cell lines. Expression of a constitutively active chimeric receptor consisting of ErbB2 and ErbB3 in HCC2998 cells, a highly differentiated adenocarcinoma cell line, revealed that the signaling triggered by phosphorylation of ErbB3 was important for dedifferentiated phenotypes such as loss of cell-cell interaction and high expression of MUC1/DF3 antigen, a marker of the malignant tumors. Taken together, activation of ErbB3 pathway may contribute to the development of dedifferentiated carcinomas.

Phospholipase D activity in human gastric carcinoma.

Growth factor-stimulated phospholipase D (PLD) catalyzes the hydrolysis of phosphatidylcholine, generating phosphatidic acid which may act as a second messenger during cell proliferation, therefore PLD is believed to play an important role in tumorigenesis. Thus we measured PLD activity in human gastric carcinoma to evaluate its role in gastric carcinogenesis. PLD activity was assayed by a unique transphosphatidylation reaction using microsomal fraction of 21 pairs of surgically resected human gastric carcinomas and adjacent noncancerous mucosas. The mean PLD activities in gastric carcinoma and adjacent noncancerous mucosa were 63.0 +/- 69.5, 44.2 +/- 60.1 pmol/min/mg, respectively (p < 0.01; Wilcoxon signed rank test). The mean ratio of PLD activity in gastric carcinoma and adjacent noncancerous mucosa was 1.63. This ratio was significantly higher in patients with larger tumors (> or = 5 cm) (p < 0.01; Mann-Whitney U-test). Our results indicate that the elevation of PLD activity plays an important role in the promotion of gastric carcinoma.

Immunohistochemical evaluation of thymidylate synthase in gastric carcinoma using a new polyclonal antibody: the clinical role of thymidylate synthase as a prognostic indicator and its therapeutic usefulness.

BACKGROUND: Before this study was conducted, the clinical and therapeutic significance of immunohistochemical evaluation of thymidylate synthase (TS) in patients with gastric carcinoma had not yet been clarified. METHODS: TS was immunohistochemically evaluated in 134 gastric carcinomas using anti-TS antibody. TS expression, 11 clinicopathologic variables, and survival were studied, and the correlations among them were investigated. RESULTS: The groups with high and low TS levels consisted of 56 and 78 patients, respectively. Granular cytoplasmic staining patterns of tumor cells were produced by immunohistochemical staining of the gastric carcinoma tissues. The grade of TS staining was significantly correlated with three clinicopathologic variables: depth of invasion, peritoneal metastasis, and stage of the carcinoma (P < 0.05). A univariate analysis revealed that the 5-year survival was significantly better for the low TS group than for the high TS group (P < 0.05): 65.2% for the low TS group and 43.2% for the high TS group. The group with high grade TS staining who received chemotherapy because of the advanced stage of their disease had worse prognoses even if they received adjuvant chemotherapy. A multivariate analysis revealed that four variables (peritoneal metastasis, lymphatic invasion, liver metastasis, and TS staining grade) independently contributed to survival (P < 0.05). The hazard ratio for the group with low grade TS staining was 0.464 compared with the group with high grade staining. CONCLUSIONS: The immunohistochemical evaluation of TS using this anti-TS antibody may be clinically and therapeutically useful in determining the prognosis of gastric carcinoma patients.

[An immunohistochemical double labelling study on type IV collagenase and basement membrane in human colonic carcinoma].

OBJECTIVE: To investigate the relationship between type IV collagenase and basement membrane (BM) and the relationship between type IV collagenase and p21 expression. METHODS: Immunohistochemical double labelling technique was used to study paraffin embedded sections of 86 cases of colon carcinoma. RESULTS: The positive rate of type IV collagenase was 83.72% in carcinoma cases and 10% in normal colorectal mucosa (P < 0.01). Intact BM was seen in normal colorectal mucosa while BM was disrupted and fragmentary in carcinoma cases. A close positive correlation was also found between the expression of type IV collagenase and p21 in colonic carcinoma (r = 0.974, P < 0.01). CONCLUSIONS: The results suggest that type IV collagenase plays an important role in the destruction of BM and invasion by colonic carcinoma.

Overexpression of cyclin-dependent kinase-activating CDC25B phosphatase in human gastric carcinomas.

CDC25 phosphatases activate cyclin-dependent kinases by removing inhibitory phosphate groups on the molecules and positively regulate the cell cycle progression. The expression of CDC25A, B and C was examined in gastric carcinoma cell lines and gastric carcinoma tissues by northern blotting and immunohistochemistry. The gastric carcinoma cell lines expressed CDC25A, B and C mRNA at various levels. The expression levels of CDC25B were generally higher than those of CDC25A and C. Of the 40 gastric carcinomas, 70% of the tumors expressed CDC25B mRNA at higher levels than the corresponding normal mucosas, while 38% overexpressed CDC25A mRNA. The CDC25C expression was at very low or undetectable levels. No obvious correlation was detected between the expression of CDC25B and p53 gene mutations. Immunohistochemically, CDC25-positive tumor cells were detected in 43 (78%) of 55 gastric carcinoma cases, of which 27 (49%) were strongly positive. Strong expression of CDC25B protein was associated with advanced stage and deep invasion. Furthermore, the incidence of strong expression was significantly higher in carcinomas with nodal metastasis than in those without metastasis. These findings suggest that overexpression of CDC25B may favor development and progression and may be an indicator of malignant behavior of gastric carcinomas.

Effects of apple pectin on fecal bacterial enzymes in azoxymethane-induced rat colon carcinogenesis.

Because of the potential significance of colonic bacteria in colon carcinogenesis, we investigated the effect of pectin of different types on fecal bacterial enzymes (beta-glucuronidase, beta-glucosidase and tryptophanase) at various periods of time after feeding rats with pectin-containing diets during azoxymethane-induced colon carcinogenesis. The diet supplemented with 20% apple pectin or 20% citrus pectin decreased the multiplicity of colon tumors, and the number of tumors was significantly decreased in the group fed apple pectin. The incidence of colon tumors in the apple pectin group was lower than that in the control group. The mean tumor size was similar among the three groups. Apple pectin feeding decreased fecal beta-glucosidase and tryptophanase levels. Furthermore, a significant decrease in the activity of beta-glucuronidase was observed in the apple pectin group during the initiation phase. These findings suggest that the protective effect of pectin on colon carcinogenesis may be dependent on the type of pectin and be related to the decrease of beta-glucuronidase activity in the initiation stage of carcinogenesis.