Revision of gastrointestinal mesenchymal tumours with CD117.

BACKGROUND: Tyrosinekinase inhibitors improve the treatment of gastrointestinal stromal tumours (GISTs) and their diagnosis has been facilitated by recently developed immunohistochemical markers. It is hypothesised that in the past, the true incidence of GISTs has been underestimated. AIMS: To study the clinicopathological features of previously resected mesenchymal tumours of the gastrointestinal tract and determine the accuracy of previous diagnostic results. PATIENTS AND METHODS: Patients with mesenchymal tumours of the gastrointestinal tract operated on between 1987 and 2002 were identified using medical and pathologic files. Immunohistochemical staining for CD117, CD34, desmin and S100 was performed, and diagnosis reviewed. RESULTS: Thirty-six mesenchymal tumours were reanalysed. Before revision, diagnosis of GIST was correctly made in only six cases. Supportive use of immunohistochemical markers for accurate diagnosis of the remaining 30 previously undefined mesenchymal tumours yielded 17 additional GISTs. Therefore, 23 of 36 (63%) gastrointestinal mesenchymal tumours were shown to be GISTs. CONCLUSIONS: The true incidence of GISTs has been underestimated. There is merit in reviewing the clinical diagnoses of all mesenchymal tumours of the gastrointestinal tract with modern immunohistochemical markers. This may enhance clinical decision making.

Ridogrel enemas in distal ulcerative colitis.

OBJECTIVE: To evaluate the effect of Ridogrel enemas (Janssen Research Foundation, Beerse, Belgium) on disease activity and mucosal inflammatory mediators in patients with active left-sided ulcerative colitis. DESIGN AND METHODS: Eleven patients with active left-sided ulcerative colitis were evaluated in an open non-placebo-controlled pilot study. All patients were treated with Ridogrel enemas (300 mg/40 ml once daily) over four weeks. A disease activity score based on clinical, endoscopic and histological criteria was obtained before and after treatment with Ridogrel. The concentrations of thromboxane B2 (TxB2), prostaglandin E2 (PGE2), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) were measured in mucosal biopsies before and after treatment. RESULTS: One patient discontinued treatment because of progression of disease, the other ten patients tolerated the Ridogrel enemas well. Mucosal TxB2 concentration decreased significantly in all patients. The mucosal concentrations of the other inflammatory mediators (PGE2, IL-6 and TNF-alpha) were unaltered. The disease score decreased in five patients. However, clinical improvement was not always associated with a decrease in endoscopic and/or histological scores. CONCLUSIONS: This pilot study shows that Ridogrel enemas selectively reduce mucosal TxB2 concentration.

Effect of fibrin sealant on the integrity of colonic anastomoses in rats with faecal peritonitis.

OBJECTIVE: To assess the influence of fibrin adhesive on the healing of colonic anastomoses in rats with and without faecal peritonitis. DESIGN: Controlled study. SETTING: Laboratory for experimental surgery, Erasmus University Rotterdam, The Netherlands. MATERIAL: 120 male Wag/Rij rats. INTERVENTIONS: All rats had a single layer end-to-end anastomosis fashioned with 7/0 polypropylene. Faecal peritonitis was then induced in half of the rats by placement of 200 mg powdered autoclaved rat faeces in the peritoneal cavity near the anastomosis. Rats were allocated to one of four groups (n = 30 in each): 1--control; 2--additional sealing with fibrin glue; 3--peritonitis alone; and 4--peritonitis with fibrin glue. MAIN OUTCOME MEASURES: Body weight, adhesion formation, anastomotic bursting pressure and collagen concentration around the anastomosis on days 2, 4, and 7 in 10 rats from each group. RESULTS: 11 rats died of peritonitis before the experiment was completed. Peritonitis caused increased formation of adhesions and abscesses, with or without fibrin sealant. Bursting pressure at the anastomosis was significantly reduced in peritonitis compared with controls on days 4 and 7, and this was not prevented by fibrin. Sealing of anastomoses resulted in lower bursting pressures on day 4 in control animals. Collagen concentration was significantly reduced in peritonitis with or without fibrin sealant on days 4 and 7, and after fibrin sealing of control anastomoses. CONCLUSION: Faecal peritonitis reduced mechanical strength and collagen concentration of colonic anastomoses, and this was not prevented by additional sealing of the anastomosis with fibrin sealant.

Healing of ischemic colonic anastomosis: fibrin sealant does not improve wound healing.

Fibrin adhesives have been advocated as a protective sealant in high-risk colonic anastomoses to prevent leakage. To assess the effect of fibrin glue sealing on the healing ischemic anastomosis, we compared the healing of sutured colonic anastomoses in the rat, with and without fibrin adhesive (Groups IA and IB), and ischemic anastomoses with and without fibrin adhesive (Groups IIA and IIB). On days two, four, and seven, 10 animals in each group were sacrificed. Adhesion formation was scored, and the in situ bursting pressure was measured. The collagen concentration and degradation were estimated by measuring hydroxyproline. Adhesion formation was more prominent in Groups IB, IIA, and IIB on day four only; abscesses were noted in the ischemic group in four rats. Anastomotic bursting pressure was significantly lower in sealed (IB) and ischemic anastomoses (IIA) than in normal anastomoses (IA) on day four. Sealing of ischemic anastomoses did not change bursting pressures on days two, four, and seven. The relative decrease of collagen in the sealed anastomoses is significantly higher on day four only. It is concluded that sealing of normal colonic anastomoses in the rat has a negative effect on wound healing. Ischemia at the anastomotic site results in weaker anastomotic strength on day four postoperatively. Also in ischemic anastomoses, fibrin sealant does not improve wound healing during the first seven days. Adhesion formation on ischemic intestinal anastomoses was not prevented by fibrin sealing.

Effect of antibiotics in fibrin sealant on healing colonic anastomoses in the rat.

In 90 rats a colonic anastomosis was constructed with 12 interrupted 7/0 polypropylene sutures. Group 1 (n = 30) served as a control group. In group 2 (n = 30) the anastomosis was sealed with fibrin adhesive and in group 3 (n = 30) a mixture of fibrin, clindamycin and cefotaxime was used. On days 2, 4 and 7, ten animals in each group were killed. Adhesion formation was significantly increased in groups 2 and 3 compared with the control group. On day 2 the anastomosis was significantly stronger after sealing with antibiotic-fibrin mixture. On day 4 the bursting pressure in group 2 was significantly lower than in groups 1 and 3. At the same time the concentration of hydroxyproline was significantly reduced in group 2, but not in group 3. The addition of antibiotics prevents the negative effect of fibrin adhesive on the healing colonic anastomosis and contributes to a stronger anastomosis on day 2 after operation.

Effect of fibrin sealant on the healing colonic anastomosis in the rat.

Fibrin adhesives have been advocated as a protective seal in colonic anastomosis to prevent leakage. In order to assess the effect of fibrin glue sealing we compared the healing of sutured colonic anastomosis in the rat (group 1) with the addition of human-derived fibrin sealant (group 2). As a control for a possible reaction to foreign protein, in group 3 the sutured anastomosis was sealed with specially prepared rat fibrin adhesive. On days 2, 4 and 7, ten animals in each group were killed. Adhesion formation was scored and the in situ bursting pressure was measured. The collagen concentration and degradation were estimated by measuring hydroxyproline. Adhesion formation was significantly increased in groups 2 and 3 compared with the control group. On days 2 and 7 the bursting pressure was not different between the groups. On day 4 the bursting pressure in groups 2 and 3 was significantly lower than in group 1 (P less than 0.001). These findings correspond with the results of collagen measurements. On day 4 the concentration of hydroxyproline was significantly reduced in groups 2 and 3. Histological examination showed infiltration of neutrophilic granulocytes into the sealant on days 2 and 4; on day 7 the sealant had vanished. From these results it is concluded that fibrin sealing of the colonic anastomosis in the rat does not improve healing, as demonstrated by bursting pressure and hydroxyproline concentration. On the contrary, it seems to have a negative influence.

Adenosine deaminase complexing protein (ADCP) expression and metastatic potential in prostatic adenocarcinomas.

The expression of the adenosine deaminase complexing protein (ADCP) was investigated by immunohistochemistry in the normal and hyperplastic human prostate, in 30 prostatic adenocarcinomas, and in seven human prostatic adenocarcinoma cell lines grown as xenografts in athymic nude mice. In the normal and hyperplastic prostate, ADCP was localized exclusively in the apical membrane and the apical cytoplasm of the glandular epithelial cells. In prostatic adenocarcinomas, four distinct ADCP expression patterns were observed: diffuse cytoplasmic, membranous, both cytoplasmic and membranous, and no ADCP expression. The expression patterns were compared with the presence of metastases. We found an inverse correlation between membranous ADCP immunoreactivity and metastatic propensity. Exclusively membranous ADCP immunoreactivity occurred only in non-metastatic tumours. In contrast, the metastatic tumours showed no or diffuse cytoplasmic ADCP immunoreactivity. This suggests that immunohistochemical detection of ADCP might predict the biological behaviour of prostatic cancer. However, the occurrence of membranous ADCP immunoreactivity in the xenograft of a cell line (PC-EW), derived from a prostatic carcinoma metastasis, indicates that not only the tendency to metastasize modulates ADCP expression.

Plasminogen activator profiles in neoplastic tissues of the human colon.

Plasminogen activator (PA) activity, in particular urokinase (u-PA), has been shown to be markedly increased in adenocarcinomas of the colon. Adenomatous polyps were found to be intermediate in their PA activity to normal mucosa and adenocarcinomas. In the present study we evaluated the PA profile in relation to malignancy parameters of the adenomas. Forty-eight adenomatous polyps, obtained by endoscopic polypectomy, were scored according to size, histological type, and grade of dysplasia. In extracts, tissue-type PA (t-PA) and u-PA were determined using a spectrophotometric enzyme assay, antigen assays, and a bioimmunoassay for u-PA. Twenty-five paired samples of normal mucosa and adenocarcinoma were used as controls. Additionally, four hyperplastic polyps were studied by the same methods. The presence of complexes of PA with PA inhibitors was assessed by zymography. A 10-fold increase of u-PA antigen in carcinomas was found as compared to normal tissue. An increase was also noted in u-PA activity, although its extent was less, due to the fact that 74% of u-PA was in the inactive proenzyme form. Adenomatous polyps contained PA activities and antigens intermediate to those of normal mucosa and carcinomas, in accordance with the view that they are precursors in the development of colorectal cancer. Within the adenoma group, no relation was found between PA profile changes and histological type or polyp size. Surprisingly, in a group of four hyperplastic polyps, similar profiles of PA were found as in adenomas. When the u-PA/t-PA antigen ratio was taken as a parameter of developing malignancy, two discrete increases were seen during the adenoma-carcinoma sequence, the first at adenoma formation and the second accompanying the start of invasive growth in polyps with severe dysplasia. Zymography showed that only t-PA was present in complex with specific PA inhibitors, explaining how the decrease of t-PA activity in adenomas and carcinomas could be stronger than the parallel decrease of t-PA antigen, when these were compared with normal mucosa, which contained hardly any complexes.

Aneuploidy and expression of gastric-associated mucus antigens M1 and CEA in colorectal adenomas.

A series of 55 flow cytometric characterized colorectal adenomas was analyzed with four different monoclonal antibodies (Mabs) for the occurrence of M1 antigens (associated with gastric fucomucins) and one Mab for carcinoembryonic antigen (CEA). The antigens were detected with an indirect immunoperoxidase technic on paraffin sections after pretreatment with pronase for M1 antigens and without pretreatment for CEA. The staining pattern revealed different correlations with the various parameters, i.e., size, histologic type, atypia, and ploidy of the adenomas. Especially the cytoplasmic staining of anti-M1, Mab (1-13 M1) correlated well with aneuploidy (R = 0.43; P less than or equal to 0.001) and with the DNA index (R = 0.34; P less than or equal to 0.01). Staining of the anti-CEA Mab only correlated with the size of the adenomas (R = 0.29; P less than or equal to 0.03). It is concluded that the immunoreactivity of Mab (1-13 M1), which significantly correlated with aneuploidy, may be associated with malignant transformation in the adenoma-carcinoma sequence.

HLA antigens in colorectal tumours--low expression of HLA class I antigens in mucinous colorectal carcinomas.

Expression of HLA antigens and beta 2-microglobulin was studied by immunoperoxidase staining of frozen sections of 9 mucinous and 10 nonmucinous colorectal adenocarcinomas, 1 cloacogenic carcinoma, 12 colorectal adenomas and 4 samples of normal colorectal mucosa using monoclonal antibodies (MAbs). Staining results were related to histopathological features. HLA Class I antigens were strongly expressed in morphologically normal colorectal epithelium, in all adenomas tested and in all non-mucinous carcinomas. In contrast, expression of HLA class I antigens by the majority of tumour cells was present in only 2 of the 9 mucinous carcinomas, whereas 2 of these mucinous carcinomas were completely negative. In the mucinous carcinomas a striking scarcity of mononuclear inflammatory infiltrate, especially around the mucus accumulations, was observed. HLA class II antigen expression was not detected in normal epithelium and was only focally present in 1 of the 12 adenomas. In 6 out of the 20 carcinomas tested between 20% and 90% of the tumour cells were stained by MAbs against HLA class II antigens. Apart from the low expression of HLA class I antigens in mucinous carcinomas no relationship was found between expression of HLA antigens and histological features of the tumours. The relative poor prognosis of mucinous colorectal carcinoma as reported in the literature may be associated with low expression of HLA class I antigens and scant mononuclear inflammatory infiltrate, which may be a reflection of a weak immune response to the tumour cells.

Adenosine deaminase complexing protein (ADCP) immunoreactivity in colorectal adenocarcinoma.

Immunoreactive adenosine deaminase complexing protein (ADCP) was studied in 91 human colorectal adenocarcinomas. The expression of ADCP was correlated with that of secretory component (SC) and carcinoembryonic antigen (CEA), with the histological grade and the Dukes' stage of the carcinomas. The histological grade was scored semi-quantitatively according to 5 structural and 4 cytological variables. ADCP expression was observed in 3 different staining patterns, namely: (1) diffuse cytoplasmic (77% of the carcinomas); (2) granular cytoplasmic (13%); and (3) membrane-associated (66%). These patterns were observed alone or in combination. Eleven percent of the carcinomas exhibited no ADCP immunoreactivity. Linear regression analysis showed that the expression of ADCP correlates with that of SC and CEA. However, no significant correlation emerged between the histological parameters or the Dukes' stage and any of the immunohistological parameters. Comparison of the histological characteristics of carcinomas exhibiting little or no ADCP immunoreactivity with those showing extensive immunoreactivity, showed that membranous ADCP immunoreactivity occurs more frequently in well-differentiated carcinomas. Structural parameters showed a better correlation with membranous ADCP expression than the cytological variables. It is concluded that membranous expression of ADCP and CEA are indicators of a high level of differentiation as reflected primarily in the structural characteristics of the tumor.

Neuroendocrine cells in colorectal adenomas.

A consecutive series of 218 endoscopically resected colorectal adenomas was investigated for the occurrence of neuroendocrine cells. In 59 per cent of these adenomas argyrophil cells were detected. In 8 per cent of the adenomas these cells were numerous and so intricately blended in with the other cell types that they were regarded as an intrinsic part of the tumour. In these adenomas subsequently immunocytochemistry revealed the presence of the neuro-hormonal peptides glucagon, pancreatic polypeptide and somatostatin as well as serotonin, in a pattern similar to that seen in normal colorectal mucosa. The presence of neuroendocrine cells did not correlate with any clinical or pathological parameter. The occurrence of neuroendocrine cells in colorectal adenomas is in agreement with the unitarian theory of the development of the various epithelial cell types in large bowel mucosa.

Flow cytometric detection of aneuploidy in colorectal adenomas.

Flow cytometry has been used to study the incidence of aneuploidy in a series of 55 colorectal adenomas (29 tubular adenomas, 22 tubulovillous adenomas, and 4 villous adenomas). For comparison, 5 nonadenomatous polyps, 4 normal mucosa samples from colectomy specimens and 16 colorectal cancers were measured. Fifteen (27%) adenomas were aneuploid, 33 (63%) were diploid, and 7 (11%) were peridiploid. The aneuploidy incidence increased with the size of the adenomas (less than 1 cm, 0%; 1 to 2 cm, 30%; greater than 2 cm, 50% aneuploid cases, respectively) but was less dependent on the histological type or degree of dysplasia. However, the degree of aneuploidy [mean DNA index of aneuploid stem lines] was significantly higher in tubulovillous adenomas [1.26 +/- 0.33 (SD)] than in tubular adenomas [1.09 +/- 0.04] and only slightly lower than in carcinomas [1.59 +/- 0.26]. The progressive increase in ploidy abnormality with size and histological type strongly supports the evidence for the adenoma-carcinoma sequence in the development of colorectal cancer.