p53 Mutations in carcinoma of the esophagus and gastroesophageal junction.

BACKGROUND: Recent studies suggested p53 mutations as a prognostic factor. Tumors of the esophagus and gastroesophageal (GE) junction show raising incidence with a general poor prognosis. METHODS: p53 Mutational spectra in 103 patients (68 squamous cell carcinoma/SCC and 35 adenocarcinoma/AC) were compared to clinical and pathologic data. RESULTS AND CONCLUSIONS: p53 Mutations were found in 26 of 68 SSC (38.2%) and in 12 of 35 AC (34.5%). We only found G > T transversions in smokers with SCC. The survival of patients was not affected by p53 mutational status. In our study, the frequency and mutational spectrum of mutant p53 is similar in both histological types without prognostic relevance.

Autologous blood vessels engineered from peripheral blood sample.

OBJECTIVE: Although many efforts have been made to generate small-diameter (< or =5mm) vascular grafts by means of tissue engineering, improvement in patency and functionality still remains a great challenge. It is our hypothesis that to achieve long-term functionality and patency, not only the complete lining with endothelial cells but also full biocompatibility is essential. DESIGN: The aim was the development of a conduit from a scaffold and endothelial progenitor cells (EPC) separated from peripheral blood of a single donor. MATERIALS AND METHODS: EPC and a fibrin preparation were separated from porcine peripheral blood. Fibrin segments were generated seeded with EPC and were perfused in a bioreactor in vitro. RESULTS: From 100ml blood 12-15 cm long fibrin tubes were successfully generated lined with endothelial-like cells. Seeded tubes showed a remarkable elasticity and burst strength up to 90 mm mercury. CONCLUSIONS: Stable fibrin tubes were successfully generated completely lined with an endothelium-like monolayer from fibrin and EPC, both isolated from the same volume of blood. Although their stability is not those needed for arterial grafting, our results raise the hope, that with distinct improvements in future studies functional autologous vascular grafts could be engineered from the patient's own blood.

Influence of thymidylate synthase and p53 protein expression on clinical outcome in patients with colorectal cancer.

AIMS: Thymidylate synthase (TS) and tumor suppressor p53 are two proteins with an influence on tumor resistance to radio-chemotherapy that is well known. For this reason we tested the effect of TS and p53 expression on clinical outcome (tumor recurrence and survival) in patients after curative tumor resection, especially in patients who received adjuvant radio-chemotherapy. PATIENTS AND METHODS: A total of 120 patients with colorectal cancer were included in the study. A curative resection was possible in 83 patients, and 30 of this group received adjuvant therapy. For the immunohistochemical staining of tumor specimens, monoclonal antibody (mAb) TS 106 against TS and mAb DO-1 against p53 protein were used. TS positivity was defined as a moderate to high staining intensity in the cytoplasma of cells and p53 positivity as nuclear staining of tumor cells in >10% of these cells. RESULTS: Thymidylate synthase immunoreactivity was found in 59% of all cases and p53 staining in 51%. No relation between clinicopathological features and p53 expression was found in contrast to TS expression, where a highly significant association of TS-positive cases with tumor invasion (pT) was observed. Curatively resected patients with a TS-positive tumor developed tumor recurrence/distant metastases significantly more often than TS negative tumors. The same result was found when comparing p53-positive with p53-negative tumors and TS+/p53+ with TS-/p53- tumors. TS expression was highly significantly associated with poor survival and was the strongest independent prognostic factor in multivariate analysis, followed by lymph node status. CONCLUSION: Thymidylate synthase expression seems to be an independent prognostic factor and a possible predictor of tumor recurrence in patients with colorectal cancer.

Colorectal carcinomas with high MIB-1 labelling indices but low pKi67 mRNA levels correlate with better prognostic outcome.

AIMS: Antibodies specific to the proliferation-associated protein pKi67 (e.g. Ki67, MIB-1) are routinely used in oncology to assess the proliferation index of tumour cells. In untransformed cells the amount of pKi67 present at any time of the cell cycle is strictly regulated. To achieve a better understanding of expression and regulation of this protein in tumour cells, we investigated both pKi67 mRNA and protein expression in routinely fixed and embedded tissue of colorectal carcinoma. METHODS AND RESULTS: We determined a median pKi67 specific in-situ hybridization labelling index of 42% (9-79%) and a median Ki67 index (MIB-1 labelling index) of 59% (26-94%) in 47 resected colorectal adenocarcinomas of different stages and grades. In 32 cases expression of pKi67 mRNA and protein correlated well but we observed a significant difference between both values in 15 tumours. In these cases more than 30% of the cells expressed the protein but not the mRNA of pKi67, possibly due to cell cycle arrest. Patients belonging to this group had a significantly (P < 0.012) better prognosis. CONCLUSIONS: Tumours with a high pKi67 protein level but low mRNA expression are likely to proliferate more slowly than calculated on the basis of their Ki67 staining index, which possibly explains the patients' improved outcome.

[Influence of resterilized polypropylen meshes on growth of human fibroblasts--an experimental in vitro study]. / Einfluss resterilisierter Kunststoffnetze aus Polypropylen auf das Wachstum humaner Fibroblasten--Eine experimentelle in vitro Studie.

INTRODUCTION: We investigated the influence of resterilized polypropylen meshes (Prolene(R)) on proliferation and apoptosis of human fibroblasts in an experimental in vitro study. METHOD: Human fibroblasts were seeded into six-well culture dishes in a density of 3 x 10 (4) cells/well. After resterilization of meshes (steam autoclave, 121 degrees C, 20 min.) according to the manufacturer's recommendations (Ethicon, Norderstedt) square sheets of 2 x 2 cm were incubated with fibroblasts over a period of 6, 12, 18, 24, 30, 36, 42 and 48 h. Preparations of fibroblasts with non-resterilized meshes and without meshes served as controls. Proliferation index and apoptotic index were estimated by flow cytometry after cell staining with an FITC-conjugated antibody against the Ki-67 antigen or with FITC-conjugated Annexin-V and propidium jodide, respectively. RESULTS: A significant reduction of the proliferation index from 86 % to 42 % was found after 48 h incubation of cells with resterilized meshes, whereas only a slight decrease was found in the group with non-resterilized meshes (75 %) and in controls without meshes (80 %). Apoptotic index increased significantly from 2 % to 48 % after 48 h incubation with resterilized meshes in comparison to both control groups, where only a slight increase could be observed: non-resterilized meshes to 19 % and without meshes to 10 %. CONCLUSION: Resterilized meshes inhibit growth of human fibroblats in vitro significantly, demonstrated by a reduced proliferative activity and an increased apoptotic index. This could be caused by a release of toxic substances from the meshes, which have a negative influence on cell growth. Therefore, resterilization cannot be recommended.

Innate immunity and colonic inflammation: enhanced expression of epithelial alpha-defensins.

Human alpha-defensins contribute to local intestinal host defense as part of innate immunity and may be of major relevance in microbial infection and chronic inflammatory bowel disease. The objective was to investigate human defensin 5 and 6 (HD-5, HD-6) mRNA expression by RT-PCR from colonic biopsies and peptide expression by immunohistochemistry from colonic resections under basal and inflammatory conditions. Both alpha-defensins were induced by proinflammatory cytokines in cell culture. HD-5 mRNA expression was enhanced in both idiopathic and nonidiopathic inflammatory states of the large bowel [32% of control vs 73% of unspecific colitis, 69% of Crohn's disease (CD) and 73% of ulcerative colitis (UC)], whereas HD-6 was specifically related to CD and UC (14% in controls vs 20% in unspecific coltis, 49% in CD and 42% in UC). Immunohistochemistry confirmed the presence of HD-5 in colonic epithelium. Antimicrobial peptides in the colon may be of importance in maintaining the mucosal barrier and controlling microbial invasion in inflammatory bowel diseases.

[Polypropylene synthetic mesh modifies growth of human cells in vitro. An experimental study]. / Kunststoffnetze aus Polypropylen beeinflussen das Wachstum humaner Zellen in vitro. Eine experimentelle Studie.

INTRODUCTION: The aim of our study was to investigate the influence of polypropylene meshes on the proliferation and apoptosis of human cell cultures in vitro. METHODS: Human fibroblasts and HeLa cells were incubated in different densities (10(4), 3.10(4), 10(5) cells/well) together with polypropylene meshes (Prolene, 2 x 2 cm) in six-well culture dishes over a 48-h period. Cells without meshes served as controls. Cells were spun on slides and stained with the monoclonal antibody MIB-1. To calculate the proliferation indices, stained nuclei were counted. Apoptotic indices were determined by flow cytometric analysis, using FITC-conjugated Annexin-V and propidiumjodide for staining. RESULTS: Fibroblasts showed only a slight reduction of the proliferation index (PI) from 64% (controls) to 60% (meshes). Increasing cell density leads to a decrease in the PI of both groups. The PI of HeLa cells was similar in mesh groups and controls and independent of cell density. The apoptotic index (AI) of fibroblasts was significantly higher in the mesh group (3.7%) in comparison with the controls (1.9%). The same was observed for HeLa cells (AI mesh group: 4.5%, AI controls: 1.2%). Furthermore, an increase of AI was found with increasing cell density in both cell lines. CONCLUSION: Whereas meshes did not influence the proliferation of the cell lines examined, they seem to have a marked influence on apoptosis, as a significant increase of AI was observed in the mesh group in contrast to controls.

Assessment of proliferative activity in colorectal carcinomas by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).

The monoclonal antibody Ki-67 and the isospecific monoclonal antibody MIB-1 are routinely used in oncology to assess the proliferation index of tumor cells. A more objective and sensitive method is the determination of the of Ki-67 protein-specific mRNA by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). In 25 resected colorectal adenocarcinomas of different stages and grades we determined between 0.2 and 4.4 amol (10(-18) mol) Ki-67 protein-specific mRNA per microgram total RNA (median = 0.88 amol). The corresponding Ki-67 indices (expressing the percentage of Ki-67/MIB-I positive tumor cells) ranged from 41 to 81% (median = 61%). We found a good correlation between Ki-67 index and mRNA expression (r = 0.75), a significant correlation between both data and tumor stage (primary tumor, regional nodes, metastasis [pTNM] staging classification) (p < 0.001), but not between both data and tumor grade. Both Ki-67 indices (p = 0.05) and mRNA levels (p = 0.014) correlated significantly to the patients' survival. These results demonstrate that the Ki-67 protein-specific quantitative RT-PCR is a useful method for the characterization of tumor cell proliferation.

Prognostic significance of free gastrointestinal tumor cells in peritoneal lavage detected by immunocytochemistry and polymerase chain reaction.

AIMS: The aim of our study was to identify tumor cells in peritoneal lavage comparatively with immunocytochemistry (ICC) and half-nested reverse transcriptase-polymerase chain reaction (RT-PCR) using carcinoembryonic antigen (CEA) as marker and to evaluate their prognostic significance. PATIENTS AND METHODS: In 75 patients who underwent surgery for a carcinoma of the colorectum (n=49), stomach (n=17) or pancreas (n=9) and 13 patients with an abdominal aortic aneurysm (control group) the abdomen was irrigated with saline solution immediately after laparotomy. Cells were separated by Ficoll-density centrifugation and divided into 2 equal volumes for ICC and RT-PCR. For ICC cells were spun onto slides by cytospin centrifugation and stained with a monoclonal antibody (mab) against CEA using the APAAP method. For RT-PCR total RNA was extracted from the cells, transcribed into cDNA and amplified with CEA-specific primers. Lavages of 13 patients with an abdominal aortic aneurysm and blood samples of 6 healthy donors served as controls. RESULTS: Immunostained tumor cells were found in peritoneal lavage in 23% (17/75) of all patients, whereas 63% (47/75) of patients gave a positive result by RT-PCR analysis. In the control group (n=13) no patient presented with tumor cells in ICC, however 5 of 13 (38%) showed amplified CEA-mRNA by RT-PCR, and so did one of six blood samples. Using ICC technique, we found significant correlations between detection rates and pT-, pN-, pM-categories as well as tumor stage. On the contrary, by RT-PCR significant correlations were observed only between pT- and pM-categories and detection rates. Detection of tumor cells in peritoneal lavage with both techniques was associated with poor prognosis. Moreover, these tumor cells are an independent prognostic factor and may have an influence on the development of peritoneal carcinomatosis. CONCLUSION: ICC is a useful method for detection of tumor cells in peritoneal lavage. In contrast, half-nested RT-PCR cannot be recommended, as the detection rates are unproportionally high, obviously as a result of CEA-mRNA expression in nontumor cells.

p53 autoantibodies in sera of patients with a colorectal cancer and their association to p53 protein concentration and p53 immunohistochemistry in tumor tissue.

We evaluated p53 autoantibodies (p53-Ab) as a preoperative tumor marker and as a prognosis marker. We also investigated whether p53-Ab production is dependent on p53 protein overexpression in tumor tissue or on tumor volume. Serum samples of patients with a colorectal cancer (n = 130) and of healthy controls (n = 44) were examined for p53-Ab using an ELISA kit. P53 protein expression in tumor tissue was demonstrated immunohistochemically and quantified by ELISA. Tumor volume was calculated and patients' survival computed using the Kaplan-Meier method. p53-Ab were detected in the serum from 15% of patients; all controls were negative. There was a significant correlation between p53-Ab production and positive immunostaining or p53 protein concentration in tumor tissue. p53-Ab were detected at a higher percentage of patients with a tumor volume of 10 cm3 or greater than in those with a smaller tumor. No difference in patients' prognosis was found between the p53-Ab positive and negative groups. Because of their low sensitivity (15%) p53-Ab are not suitable as a preoperative tumor marker. However, their high specificity (100%) and their potential for early diagnosis of a tumor relapse makes them valuable for postoperative monitoring during follow-up in p53-Ab positive patients. Furthermore, their detection can be used as a simple serological test for early detection of p53 alterations.

Vascular endothelial growth factor (VEGF)--a valuable serum tumour marker in patients with colorectal cancer?

INTRODUCTION: Neo-angiogenesis, of great importance for tumour growth and nutrition, is preferentially mediated by the cytokine vascular endothelial growth factor (VEGF), which has a direct effect on vascular endothelial cell proliferation and migration. This study was designed to clarify whether VEGF is a suitable tumour marker in sera of patients with a colorectal cancer, and whether VEGF concentrations in sera and tumour tissues are correlated with tumour extension (pTNM) and especially with tumour volume or size. Furthermore, the influence of VEGF levels on patients >> prognosis was examined. METHODS: VEGF serum concentrations of 122 patients with colorectal cancer and 65 controls were determined with an ELISA kit. Additionally, VEGF concentrations of tumour and normal tissue were measured in 38 patients using the same ELISA. RESULTS: Our results demonstrate that VEGF is not a suitable diagnostic tumour marker in patients with colorectal cancer due to its low sensitivity (36%). However, a combination of the serum tumour markers CEA and VEGF can significantly increase the pre-operative diagnostic sensitivity to 62%. VEGF serum levels differed significantly between patients (mean 438 pg/ml) and controls (mean 203 pg/ml), and also between tumour and normal tissue (984 vs 89 pg/mg protein). Serum concentration showed a significant correlation to tumour volume and size. Patients with VEGF serum levels greater than cut-off had a poorer prognosis than those less than or equal to cut-off. For this reason VEGF could be used as a predictor of patients >> outcome.

Suppression of cell division by pKi-67 antisense-RNA and recombinant protein.

The human antigen defined by the monoclonal antibody Ki-67 (pKi-67) is a human nuclear protein strongly associated with cell proliferation and found in all tissues studied. It is widely used as a marker of proliferating cells, yet its function is unknown. To investigate its function we suppressed pKi-67 expression by antisense RNA and overexpressed a partial structure of pKi-67 in HeLa cells. A BrdU-incorporation assay showed a significant decrease in DNA synthesis after antisense inhibition. Cell cycle analysis indicated a higher proportion of cells in G1 phase and a lower proportion of cells in S phase while the number of G(2)/M phase cells remained constant. Overexpression of a recombinant protein encoding three of the repetitive elements from exon 13 of pKi-67 had a similar effect to that obtained by antisense inhibition. The similarity of the effect of expressing 'Ki-67 repeats' and pKi-67 antisense RNA could be explained by a negative effect on the folding of the endogenous protein in the endoplasmatic reticulum. Furthermore excessive self-association of pKi-67 via the repeat structure could inhibit its nuclear transport, preventing it from getting to its presumptive site of action. We conclude that the Ki-67 protein has an important role in the regulation of the cell cycle, which is mediated in part by its repetitive elements.

Apoptosis in rectal cancer: prognostic significance in comparison with clinical histopathologic, and immunohistochemical variables.

PURPOSE: The aim of this study was to evaluate the prognostic value of the apoptotic index for recurrence and disease-free survival after curative surgery for rectal cancer, particularly in relation to clinicopathologic variables, p53- and bcl-2 expression. METHODS: Formalin-fixed, paraffin-embedded tissue samples of rectal carcinomas resected curatively within a five-year period were used (N = 160). Apoptotic cells with fragmented DNA were detected by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphatase-biotin nick-end-labeling method. The ratio of apoptotic tumor cells (in percent) was classified into low apoptotic index (less than 10 percent) and high apoptotic index (10 percent or more). Immunohistochemical analysis was performed using monoclonal antibodies (DO-1 for p53 and clone 124 for bcl-2). Statistics included univariate and multivariate analysis, and survival was calculated using the Kaplan-Meier method. RESULTS: Seventy-five percent of tumors showed a low apoptotic index, and 25 percent had a high apoptotic index. No correlation was found between apoptotic index and International Union Against Cancer stage (P > 0.05). However, significant correlations were documented with histologic differentiation (mean apoptotic index, 5.74 percent in moderately vs. 3.98 percent in poorly differentiated carcinomas; P = 0.0173), lymph node involvement (mean apoptotic index, 6.11 percent in pN1 vs. 3.72 percent in pN2; P = 0.0074), p53 status (mean apoptotic index, 6.26 percent in p53- vs. 4.42 percent in p53+; P = 0.0085), and bcl-2 expression (mean apoptotic index, 5.13 percent in bcl-2- vs. 6.51 percent in bcl-2+; P = 0.0418). Tumors of the lower rectum had a lower apoptotic index than those of the upper rectum (P = 0.0277). Neither univariate nor multivariate analysis assessed apoptotic index as predictor of prognosis: Recurrence rates did not differ between tumors related to apoptotic index (22 percent with low apoptotic index vs. 15 percent with high apoptotic index; P > 0.05), and no significant differences were found regarding survival (P > 0.05). On multivariate analysis, International Union Against Cancer stage (P = 0.0002), p53 (P = 0.0002), gender (P = 0.0136), and bcl-2 (P = 0.0243) were independent predictors of recurrence. These variables, except for bcl-2, were also independently related to disease-free survival. CONCLUSIONS: Reflecting tumor biology, apoptotic index as single variable showed no prognostic significance, whereas p53 was an independent predictor for both recurrence and survival, and bcl-2 was independently related to recurrence, but not to survival. Clinically, International Union Against Cancer stage and gender were independent prognostic factors after curative surgery for rectal cancer.

p53 and Bcl-2 as significant predictors of recurrence and survival in rectal cancer.

The aim of this study was to evaluate the prognostic value of p53 nuclear accumulation and Bcl-2 expression after curative surgery for rectal cancer. Immunohistochemistry was performed using monoclonal antibodies (MAb) (DO-1 for p53; anti-human Bcl-2 MAb, clone 124, for Bcl-2) on formalin-fixed, paraffin-embedded tissues of 160 rectal carcinomas (UICC stages I-III), and results were compared with data from the prospective registry of rectal cancer by univariate and multivariate logistic regression model focusing specifically on recurrence. Survival was calculated by the Kaplan-Meier method and proportional hazards model. p53 nuclear accumulation was documented in 39% (n=63) of tumours and was associated with a higher incidence of tumour progression (local or distant recurrence) and poorer disease-free survival (P<0.0001). Bcl-2 expression was detected in 29% (n=47), and was associated with longer disease-free survival and lower incidence of recurrence (P<0.0086). Multivariate logistic regression analysis demonstrated that gender (P=0.0136), UICC stage (P=0.0002), p53 expression (P=0.0002) and Bcl-2 expression (P=0. 0243) were independent factors predictive of recurrence. The proportional hazards model identified p53 (P=0.0009), UICC stage (P=0.0480), gender (P=0.0049), but not Bcl-2 (P=0.1503), as independently related to disease-free survival. Looking at the p53/Bcl-2 subgroups, the poorest prognosis was observed in the p53+/Bcl-2- subgroup, whereas patients whose tumours were p53-/Bcl-2+ had the best prognosis (P<0.0001). Immunohistochemical assessment of both p53 and Bcl-2 status may be valuable in predicting recurrence and survival after curative surgery for rectal cancer. Therefore, they play a role as prognostic factors in rectal cancer. p53 is a stronger predictor of prognosis than Bcl-2.

Expression of p53 and mdm2 mRNA and protein in colorectal carcinomas.

The aim of our study was to investigate the expression of p53 and mdm2 mRNA and protein in colorectal adenocarcinoma. For the detection of mRNA, 60 fresh frozen human tumour samples and 12 samples of corresponding normal tissue were examined. After total RNA extraction, reverse transcription (RT) was performed followed by cDNA amplification with specific primers using RT-polymerase chain reaction (PCR). Immunohistochemical detection of protein was examined in 81 formalin-fixed and paraffin-embedded human tumour specimens as well as 15 samples of adjacent normal colorectal tissue. p53 mRNA was detected in 80% (48/60) of the tumours and in 67% (8/12) of normal tissue samples; 87% (52/60) of tumours had mdm2 mRNA in contrast to only 17% (2/12) of normal tissue specimens. Nuclear p53 protein expression was observed in 52% (42/81) of the tumour specimens and in none of the 15 normal specimens, whereas mdm2 protein was found in the nucleus (31%, 25/81) and also in the cytoplasm (86%, 70/81) of tumour samples. In normal tissue, mdm2 protein expression was only observed in the cytoplasm (13%, 2/15) and not in the nucleus. There was a significant correlation between coexpression of p53 and mdm2 protein and the occurrence of lymph node metastases (P = 0.03) as well as between p53 protein expression and the occurrence of distant metastases (P = 0.007). Additionally, significant associations were found between p53 mRNA and p53 protein, p53 mRNA and mdm2 mRNA or protein, and also between mdm2 mRNA and mdm2 protein expression, supporting the existence of a regulatory mechanism involving p53 and mdm2.

[Immunocytochemical and molecular proof of disseminated tumor cells in bone marrow, peritoneal lavage, blood and regional lymph nodes. A review of the literature and own results]. / Immunzytochemischer und molekularer Nachweis disseminierter Tumorzellen im Knochenmark, der Peritoneallavage, dem Blut und den regionären Lymphknoten. Literaturübersicht und eigene Ergebnisse.

Immunocytochemical or molecular detection of disseminated tumor cells in different compartments (bone marrow, abdomen, venous blood, lymph nodes) is becoming more and more important in determining the complete extent of the tumor at the time of primary therapy. However, their prognostic relevance is not clear up to now. Whereas their appearance in bone marrow revealed a poor prognosis in some studies, contradictory results have been obtained from examinations of lymph nodes. Moreover peritoneal lavage and venous blood have seldom been examined with these methods. Because standardization of the immunocytochemical or molecular techniques does not exist, therapeutical conclusions can not be drawn from their detection at this time.

[Expression of P-glycoprotein in benign and malignant gallbladder neoplasms].

OBJECTIVE: To evaluate the relationship between P-glycoprotein expression and anti-cancer drug resistance of gallbladder carcinoma and the use of P-glycoprotein as a biomarker of gallbladder carcinoma, the expression of P-glycoprotein was detected in benign and malignant gallbladder neoplasms and normal gallbladder tissues. METHODS: Alkaline phosphatase anti-alkaline phosphatase (APAAP) method was used to detect the expression of P-glycoprotein in different gallbladder tissues (gallbladder carcinoma, 26 cases; benign gallbladder neoplasm, 14 cases; and normal gallbladder tissue, 9 cases). The relationship between expression of P-glycoprotein, TNM stages and other clinical data of gallbladder carcinoma was also analyzed. RESULTS: Immunohistochemical staining with a monoclonal antibody JSB-1, P-glycoprotein was positive in 76.9% (20/26) of gallbladder carcinomas, in 35.7% (5/14) of benign gallbladder neoplasms and in 33.3% (3/9) of normal gallbladder tissues (P < 0.05). With another monoclonal antibody UIC-2, the positive rates were 69.2% (18/26), 21.4% (3/14) and 11.1% (1/9), respectively (P < 0.01). There was no significant correlation between P-glycoprotein expression and gallbladder carcinoma TNM staging. CONCLUSION: The results suggest that P-glycoprotein probably plays an important role in the poor response of gallbladdar carcinoma to chemotherapeutic agents. In addition, P-glycoprotein may be used a valuable biomarker of gallbladder carcinoma.

[Detection of hL6-mRNA: new possibilities in serologic tumor diagnosis of colorectal carcinomas]. / Nachweis von hL6-mRNA: Neue Möglichkeiten der serologischen Tumordiagnostik kolorektaler Karzinome.

A study was performed to detect circulating tumor cells in patients with colorectal cancer using mRNA coding for the tumor associated antigen L6. The mRNA was determined by Reverse Transcriptase Polymerase Chain Reaction and gel-electrophoresis. The L6 results were compared with the CEA levels. Peripheral blood samples were taken from 109 patients with histologically verified colorectal cancer. Statistics were carried out using CHI Square and Sokal and Rohlf's-test. Preoperatively 81.65% showed positive L6 mRNA, whereas only 58.7% had elevated CEA titers (p < 0.05). In all patients of the control group (n = 52) no L6 was detectable. Concerning our results L6 seems to be a sensitive and precise tool for diagnosing circulating tumor cells in colorectal cancer.

Assessment of the proliferation index in gastric carcinomas with the monoclonal antibody MIB 1.

Our study aimed to reveal whether the proliferation index of tumor cells, calculated with the monoclonal antibody (mAb) MIB1, is of prognostic relevance in patients with a gastric carcinoma and shows any correlation to well-known clinicopathological factors (TNM categories, stage, grade, Laurén type). We examined formalin-fixed, paraffin-embedded tissue blocks of samples from 94 patients, who underwent surgery for an adenocarcinoma of the stomach between 1988 and 1991. Specimens were immunohistochemically stained using the mAb MIB1 in combination with the alkaline-phosphatase/anti-(alkaline phosphatase) technique. The proliferation index (PI) was estimated in various areas of interest (tumor center and periphery and in lymph node metastases of compartments I and II), by always counting 200 tumor cells in three different high-power fields per specimen, and calculated as the percentage of MIB1-positive tumor cell nuclei relative to all tumor cell nuclei in the area examined. The total PI in the primary tumor was 47.2% and slightly higher in the center (49.1%) compared to the periphery (44.7%). Surprisingly in lymph node metastases the PI was lower than in the primary tumor (compartment I: 39.5%, compartment II: 33.6%). Tumors with distant metastases revealed a higher proliferative activity (55.1%) than tumors without (44.3%). The PI increased significantly from well to poorly differentiated carcinomas (P < 0.01), whereas the intestinal Laurén type showed a lower PI than the diffuse type. No difference in survival was found between patients with a median PI or less and those with a PI above the median (47.2%). Our results show that the proliferation index in gastric carcinomas has no prognostic relevance and therefore is of low clinical value.