Colectomy with ileostomy for severe ulcerative colitis-postoperative complications and risk factors.

PURPOSE: In the era of biological therapy of ulcerative colitis (UC), surgical treatment frequently consists of colectomy, end ileostomy, and rectal stump closure before patients go on towards restorative proctocolectomy. We aimed to evaluate possible risk factors for the occurrence of postoperative complications and investigate those after initial colectomy in these patients. METHODS: Retrospective analysis of 180 patients (76 female, 104 male) undergoing colectomy for UC with formation of a rectal stump and terminal ileostomy between March 2008 and March 2018 at Charité University Hospital Berlin, Campus Benjamin Franklin. A panel of possible postoperative complications was established, patient history was screened, and postoperative complications were analyzed using the Clavien Dindo Classification. RESULTS: Postoperative complication rate was 27.7%. Mortality was 0.5%. Postoperative ileus occurred in 15.3% and rectal stump leakage in 14.8%. Complications were categorized as Clavien Dindo 3 in 80%. Risk factors for surgical complications after multivariate analysis were ASA classification (p = 0.004), preoperative anemia (Hemoglobin < 8 mg/dl) (p = 0.025), use of immunosuppressants (p = 0.003), more than two cardiovascular diseases (p = 0.016), and peritonitis (p = 0.000). Reoperation rate of patients with surgical complications was 27.7%. CONCLUSION: Colectomy in high-risk UC patients is associated with significant morbidity. However, most of the surgical complications can be treated conservatively. Overall mortality is low. Patient-related risk factors are associated with postoperative complications. Optimizing these risk factors or earlier indication for surgery in the course of UC may help to reduce morbidity of this procedure.

Calprotectin as Diagnostic Marker for Hepatic Encephalopathy and Spontaneous Bacterial Peritonitis in Cirrhosis.

BACKGROUND: Calprotectin is a well-established marker for intestinal inflammation, mainly in inflammatory bowel disease, and represents one of the most studied biomarkers in stool samples. METHODS: Apart from its important diagnostic role in inflammatory bowel disease, there are few studies showing that calprotectin can also be used as a diagnostic tool in patients suffering from hepatic encephalopathy (HE) and spontaneous bacterial peritonitis (SBP) in cirrhosis. RESULTS: Since calprotectin concentration in the human stool or in ascites is elevated at an early stage of inflammation, it might serve as an early screening tool for patients suffering from cirrhosis who are at risk to develop these conditions. As detection and monitoring of HE and SBP may be unclear and resource-intensive, identification of valid new markers of disease activity is necessary. In this review, we summarize the current knowledge of calprotectin as a diagnostic biomarker in cirrhosis, indicating that it is a highly promising diagnostic surrogate marker to screen for the presence of HE and SBP. CONCLUSIONS: To screen cirrhotic patients for SBP, calprotectin should be assessed in ascitic fluid while it should be measured in feces when screening for HE. However, the value of calprotectin in managing individual patients must be considered in the specific clinical context.

A phase I pharmacokinetic and safety analysis of epothilone folate (BMS-753493), a folate receptor targeted chemotherapeutic agent in humans with advanced solid tumors.

Background The folate receptor alpha is selectively over-expressed in a number of human cancers. BMS-753493 is a folate conjugate of the epothilone analog BMS-748285 that was designed to selectively target folate receptor expressing cancer cells. Methods BMS-753493 was investigated in two parallel multi-institutional first-in-human phase I/IIa studies in patients with advanced solid tumors. In Study 1, patients were treated on a schedule of once daily dosing of BMS-753493 administered on Days 1, 4, 8 and 11 every 21 days with a starting dose of 5 mg daily and in Study 2, patients were treated once daily on Days 1-4 every 21 days, with a starting dose of 2.5 mg daily. Results A total of 65 patients were treated across the two studies. The maximum tolerated dose (MTD) was 26 mg in Study 1 and 15 mg in Study 2. Fatigue, transaminitis, gastrointestinal toxicity, and mucositis were dose-limiting toxicities. One patient in Study 2 developed Stevens-Johnson syndrome attributed to BMS-753493. Plasma exposures of both the conjugated and free epothilone increased in a dose related fashion in both studies and the half-life of the conjugated epothilone was 0.2-0.6 h across dose levels. No objective tumor responses were seen in either study. Conclusions BMS-753493 was generally tolerable and toxicities known to be associated with epothilone class of anticancer agents were common, although peripheral neuropathy and neutropenia appear to have been less frequent and less severe as compared to epothilones. Antitumor activity was not demonstrated and further development of BMS-753493 has been discontinued.

Exploiting Oligo(amido amine) Backbones for the Multivalent Presentation of Coiled-Coil Peptides.

The investigation of coiled coil formation for one mono- and two divalent peptide-polymer conjugates is presented. Through the assembly of the full conjugates on solid support, monodisperse sequence-defined conjugates are obtained with defined positions and distances between the peptide side chains along the polymeric backbone. A heteromeric peptide design was chosen, where peptide K is attached to the polymer backbone, and coiled-coil formation is only expected through complexation with the complementary peptide E. Indeed, the monovalent peptide K-polymer conjugate displays rapid coiled-coil formation when mixed with the complementary peptide E sequence. The divalent systems show intramolecular homomeric coiled-coil formation on the polymer backbone despite the peptide design. Interestingly, this intramolecular assembly undergoes a conformational rearrangement by the addition of the complementary peptide E leading to the formation of heteromeric coiled coil-polymer aggregates. The polymer backbone acts as a template bringing the covalently bound peptide strands in close proximity to each other, increasing the local concentration and inducing the otherwise nonfavorable formation of intramolecular helical assemblies.

Metformin attenuates ovarian cancer cell growth in an AMP-kinase dispensable manner.

Metformin, the most widely used drug for type 2 diabetes activates 59 adenosine monophosphate (AMP)-activated protein kinase (AMPK), which regulates cellular energy metabolism. Here, we report that ovarian cell lines VOSE, A2780, CP70, C200, OV202, OVCAR3, SKOV3ip, PE01 and PE04 predominantly express -α(1), -ß(1), -γ(1) and -γ(2) isoforms of AMPK subunits. Our studies show that metformin treatment (1) significantly inhibited proliferation of diverse chemo-responsive and -resistant ovarian cancer cell lines (A2780, CP70, C200, OV202, OVCAR3, SKVO3ip, PE01 and PE04), (2) caused cell cycle arrest accompanied by decreased cyclin D1 and increased p21 protein expression, (3) activated AMPK in various ovarian cancer cell lines as evident from increased phosphorylation of AMPKα and its downstream substrate; acetyl co-carboxylase (ACC) and enhanced ß-oxidation of fatty acid and (4) attenuated mTOR-S6RP phosphorylation, inhibited protein translational and lipid biosynthetic pathways, thus implicating metformin as a growth inhibitor of ovarian cancer cells. We also show that metformin-mediated effect on AMPK is dependent on liver kinase B1 (LKB1) as it failed to activate AMPK-ACC pathway and cell cycle arrest in LKB1 null mouse embryo fibroblasts (mefs). This observation was further supported by using siRNA approach to down-regulate LKB1 in ovarian cancer cells. In contrast, met formin inhibited cell proliferation in both wild-type and AMPKα(1/2) null mefs as well as in AMPK silenced ovarian cancer cells. Collectively, these results provide evidence on the role of metformin as an anti-proliferative therapeutic that can act through both AMPK-dependent as well as AMPK-independent pathways.

The effect of dentin desensitizer on shear bond strength of conventional and self-adhesive resin luting cements after aging.

This study tested the impact of Gluma Desensitizer on the shear bond strength (SBS) of two conventional (RelyX ARC, Panavia 21) and two self-adhesive (RelyX Unicem, G-Cem) resin luting cements after water storage and thermocycling. Human third molars (N=880) were embedded in acrylic resin. The buccal dentin was exposed. Teeth were randomly divided into four main groups, and the following cements were adhered: 1) RelyX ARC, 2) Panavia 21, 3) RelyX Unicem, and 4) G-Cem. In half of the teeth in each group, dentin was treated with Gluma Desensitizer. In the conventional cement groups, the corresponding etchant and adhesive systems were applied. SBS of the cements was tested after 1 hour (initial); at 1, 4, 9, 16, and 25 days of water storage; and at 1, 4, 9, 16, and 25 days of thermocycling. SBS data were analyzed by one-way analysis of variance (ANOVA); this was followed by the post hoc Scheffé test and a t-test. Overall, the highest mean SBS (MPa) was obtained by RelyX ARC (ranging from 14.6 ± 3.9 to 17.6 ± 5.2) and the lowest by Panavia 21 in combination with Gluma Desensitizer (ranging from 0.0 to 2.9 ± 1.0). All tested groups with and without desensitizer showed no significant decrease after aging conditions compared with baseline values (p>0.05). Only the Panavia 21/Gluma Desensitizer combination showed a significant decrease after 4 days of thermocyling compared with initial values and 1 day thermocycling. Self-adhesive cements with Gluma Desensitizer showed increased SBS after aging conditions (ranging from 7.4 ± 1.4 to 15.2 ± 3) compared with groups without desensitizer (ranging from 2.6 ± 1.2 to 8.8 ± 2.9). No cohesive failures in dentin were observed in any of the test groups. Although self-adhesive cements with and without desensitizer presented mainly adhesive failures after water storage (95.8%) and thermocyling (100%), conventional cement (RelyX ARC) showed mainly mixed failures (90.8% and 89.2%, after water storage and thermocyling, respectively). Application of the Gluma Desensitizer to dentin before cementation had a positive effect on the SBS of self-adhesive cements.

From randomized trial to practice: single institution experience using the GOG 172 i.p. chemotherapy regimen for ovarian cancer.

BACKGROUND: The objective of the study was to evaluate completion rates and toxic effects of an i.p. chemotherapy regimen in a cross-section of nonselected patients with ovarian cancer (OC). PATIENTS AND METHODS: All patients with stage IIIC OC consecutively operated at our institution from January 2006 to December 2007 were prospectively collected and analyzed. RESULTS: Eighty-nine patients with stage IIIC OC optimally debulked were evaluated for this study. An i.p. port was primarily placed in 53 of 89 (60%), and i.p. chemotherapy was recommended in 55 patients. Reasons for not recommending i.p. chemotherapy in patients optimally debulked included postoperative complications (n = 7: 8%), poor nutritional/functional status (n = 5: 6%), and extensive surgery including bowel resection (n = 9: 10%). Thirty-three patients (33/55: 60%) recommended to receive i.p. chemotherapy-initiated i.p. treatment. Fifty-two percent of those beginning i.p. therapy (17/33) received three or more cycles with 36% (12/33) successfully completing six cycles. Reasons for discontinuation included grade 3-4 nephrotoxicity in 3 of 21 (14%), febrile neutropenia/sepsis in 3 of 21 (14%), port infection or malfunction in 8 of 21 (38%). CONCLUSIONS: The i.p. chemotherapy regimen used in a consecutive cohort of patients carries could be completed in only a small percentage of patients. Less toxic regimens with higher acceptability should be considered.

Clinical and ultrasonographic correlation between scapular dyskinesia and subacromial space measurement among junior elite tennis players.

OBJECTIVES: In this study, the hypothesis that tennis players with scapular dyskinesia present a smaller subacromial space than non-athletes was investigated. Additionally, the correlation between the size of the subacromial space and abnormalities in scapular movement during arm abduction was studied. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 53 elite tennis players and 20 control participants were enrolled in the study. Participation was restricted to elite-level, junior tennis players who had no current shoulder pain or history of shoulder injuries. INTERVENTION: Each individual was examined for scapular dyskinesia by a single physician and by ultrasound, with the results analysed in a blind fashion by a single radiologist. RESULTS: 43.4% of the tennis players and 20% of control participants presented with scapular dyskinesia. Of the 106 shoulders evaluated, 39.6% of tennis players and 10% of control participants presented with scapular dyskinesia in the clinical examination (p = 0.005). Ultrasonographic measurements demonstrated that tennis players presented statistically smaller subacromial spaces compared with control participants (p<0.001). A decrease in the subacromial space was observed in tennis players when the shoulder was raised from 0 degrees to 60 degrees of abduction; however, dyskinesia-afflicted athletes demonstrated a significantly greater decrease following this movement (19.3 vs 13.8 mm, p = 0.002). CONCLUSIONS: The results of this study demonstrated that tennis players with scapular dyskinesia present a smaller subacromial space than control participants. Furthermore, when the shoulder was analysed dynamically, moving from neutral abduction to 60 degrees of elevation, the tennis players with scapular dyskinesia presented a greater reduction in the subacromial space compared with unaffected athletes.

Politics of psychiatry.

In the letter "Politics of psychiatry" (23 Mar., p. 1184), the first signature should have been Paul L. Watson, not Peter L. Watson.

The CIDA-QUEST large-scale survey of Orion OB1: evidence for rapid disk dissipation in a dispersed stellar population.

We are conducting a large-scale, multiepoch, optical photometric survey [Centro de Investigaciones de Astronomia-Quasar Equatorial Survey Team (CIDA-QUEST)] covering about 120 square degrees to identify the young low-mass stars in the Orion OB1 association. We present results for an area of 34 square degrees. Using photometric variability as our main selection criterion, as well as follow-up spectroscopy, we confirmed 168 previously unidentified pre-main sequence stars that are about 0.6 to 0.9 times the mass of the sun (Mo), with ages of about 1 million to 3 million years (Ori OB1b) and about 3 million to 10 million years (Ori OB1a). The low-mass stars are spatially coincident with the high-mass (at least 3 Mo) members of the associations. Indicators of disk accretion such as Halpha emission and near-infrared emission from dusty disks fall sharply from Ori OB1b to Ori OB1a, indicating that the time scale for disk dissipation and possibly the onset of planet formation is a few million years.

Reggies/flotillins regulate cytoskeletal remodeling during neuronal differentiation via CAP/ponsin and Rho GTPases.

The reggies/flotillins were discovered as proteins upregulated during axon regeneration. Here, we show that expression of a trans-negative reggie-1/flotillin-2 deletion mutant, R1EA, which interferes with oligomerization of the reggies/flotillins, inhibited insulin-like growth factor (IGF)-induced neurite outgrowth in N2a neuroblastoma cells and impaired in vitro differentiation of primary rat hippocampal neurons. Cells expressing R1EA formed only short and broad membrane protrusions often with abnormally large growth cones. R1EA expression strongly perturbed the balanced activation of the Rho-family GTPases Rac1 and cdc42. Furthermore, focal adhesion kinase (FAK) activity was also enhanced by R1EA expression, while other signaling pathways like ERK1/2, PKC or PKB signaling were unaffected. These severe signaling defects were caused by an impaired recruitment of the reggie/flotillin-associated adaptor molecule CAP/ponsin to focal contacts at the plasma membrane. Thus, the reggies/flotillins are crucial for coordinated assembly of signaling complexes regulating cytoskeletal remodeling.

Methylated bismuth, but not bismuth citrate or bismuth glutathione, induces cyto- and genotoxic effects in human cells in vitro.

Bismuth compounds are widely used in industrial processes and products. In medicine, bismuth salts have been applied in combination with antibiotics for the treatment of Helicobacter pylori infections, for the prevention of diarrhea, and in radioimmunotherapy. In the environment, bismuth ions can be biotransformed to the volatile bismuth compound trimethylbismuth (Me3Bi) by methanobacteria. Preliminary in-house studies have indicated that bismuth ions are methylated in the human colon by intestinal microflora following ingestion of bismuth-containing salts. Information concerning cyto- and genotoxicity of these biomethylated products is limited. In the present study, we investigated the cellular uptake of an organic bismuth compound [monomethylbismuth(III), MeBi(III)] and two other bismuth compounds [bismuth citrate (Bi-Cit) and bismuth glutathione (Bi-GS)] in human hepatocytes, lymphocytes, and erythrocytes using ICP-MS. We also analyzed the cyto- and genotoxic effects of these compounds to investigate their toxic potential. Our results show that the methylbismuth compound was better taken up by the cells than Bi-Cit and Bi-GS. All intracellularly detected bismuth compounds were located in the cytosol of the cells. MeBi(III) was best taken up by erythrocytes (36%), followed by lymphocytes (17%) and hepatocytes (0.04%). Erythrocytes and hepatocytes were more susceptible to MeBi(III) exposure than lymphocytes. Cytotoxic effects of MeBi(III) were detectable in erythrocytes at concentrations >4 microM, in hepatocytes at >130 microM, and in lymphocytes at >430 microM after 24 h of exposure. Cytotoxic effects for Bi-Cit and Bi-GS were much lower or not detectable in the used cell lines up to a tested concentration of 500 microM. Exposure of lymphocytes to MeBi(III) (250 microM for 1 h and 25 microM/50 microM for 24 h) resulted in significantly increased frequencies of chromosomal aberrations (CA) and sister chromatid exchanges (SCE), whereas Bi-Cit and Bi-GS induced neither CA nor SCE. Our study also showed an intracellular production of free radicals caused by MeBi(III) in hepatocytes but not in lymphocytes. These data suggest that biomethylation of bismuth ions by the intestinal microflora of the human colon leads to an increase in the toxicity of the primary bismuth salt.

[Measurement of the central corneal power after myopic LASIK]. / Evaluation der zentralen Hornhautbrechkraft nach myoper LASIK.

PURPOSE: Comparison of the central corneal refractive power before and after myopic LASIK using the Keratograph and the Pentacam. The Scheimpflug technique (Pentacam) enables the measurement of the corneal refractive power by examining the anterior and posterior corneal curvature. METHOD: The corneal refractive power of 59 eyes was examined before, 3 months and 6 months after myopic LASIK. The refractive power was measured at the corneal apex and at a distance of 2 and 4 mm. Statistical analysis was performed using the Wilcoxon signed rank test; a p value of 0.05 or less was considered statistically significant. RESULTS: At the corneal apex and at a distance of 2 mm the findings with the Keratograph showed a higher refractive power of up to 1.05 D. The differences were statistically significant at all times. At a distance of 4 mm from the corneal apex postoperatively there was no statistically significant difference. CONCLUSION: The results using the Pentacam system showed a lower corneal refractive power following myopic LASIK at all times. Its measuring principle compared to that of the Keratograph should be preferred when detecting changes of the refractive power of the central cornea after corneal refractive procedures.

The cyto- and genotoxicity of organotin compounds is dependent on the cellular uptake capability.

Organotin compounds have been widely used as stabilizers and anti-fouling agents with the result that they are ubiquitously distributed in the environment. Organotins accumulate in the food chain and potential effects on human health are disquieting. It is not known as yet whether cell surface adsorption or accumulation within the cell, or indeed both is a prerequisite for the toxicity of organotin compounds. In this study, the alkylated tin derivatives monomethyltin trichloride (MMT), dimethyltin dichloride (DMT), trimethyltin chloride (TMT) and tetramethyltin (TetraMT) were investigated for cyto- and genotoxic effects in CHO-9 cells in relation to the cellular uptake. To identify genotoxic effects, induction of micronuclei (MN), chromosome aberrations (CA) and sister chromatid exchanges (SCE) were analyzed and the nuclear division index (NDI) was calculated. The cellular uptake was assessed using ICP-MS analysis. The toxicity of the tin compounds was also evaluated after forced uptake by electroporation. Our results show that uptake of the organotin compounds was generally low but dose-dependent. Only weak genotoxic effects were observed after exposure of cells to DMT and TMT. MMT and TetraMT were negative in the test systems. After forced uptake by electroporation MMT, DMT and TMT induced significant DNA damage at non-cytotoxic concentrations. The results presented here indicate a considerable toxicological potential of some organotin species but demonstrate clearly that the toxicity is modulated by the cellular uptake capability.

Trimethylantimony dichloride causes genotoxic effects in Chinese hamster ovary cells after forced uptake.

In our study, we demonstrate that trimethylantimony dichloride (TMSb) does not induce micronucleus (MN) formation, chromosome aberrations (CA) or sister chromatid exchanges (SCE) under normal conditions in Chinese hamster ovary (CHO-9) cells in vitro up to an applied concentration of 1 mM, nor is it significantly cytotoxic. TMSb is taken up by the cells in a dose-dependent manner, but the percentage uptake of incubation substrate is low (max 0.05%). Intracellular TMSb concentration is two-fold increased after electroporation and under these forced uptake conditions MN formation is also significantly elevated. These data indicate that resistance to TMSb in CHO-9 cells occurs at the uptake and not at the intracellular level.

Risk-reduction mastectomy: clinical issues and research needs.

Risk-reduction mastectomy (RRM), also known as bilateral prophylactic mastectomy, is a controversial clinical option for women who are at increased risk of breast cancer. High-risk women, including women with a strong family history of breast cancer and BRCA1/2 mutation carriers, have several clinical options: risk-reduction surgery (bilateral mastectomy and bilateral oophorectomy), surveillance (mammography, clinical breast examination, and breast self-examination), and chemoprevention (tamoxifen). We review research in a number of areas central to our understanding of RRM, including recent data on 1) the effectiveness of RRM in reducing breast cancer risk, 2) the perception of RRM among women at increased risk and health-care providers, 3) the decision-making process for follow-up care of women at high risk, and 4) satisfaction and psychological status after surgery. We suggest areas of future research to better guide high-risk women and their health-care providers in the decision-making process.

Efficacy of bilateral prophylactic mastectomy in BRCA1 and BRCA2 gene mutation carriers.

BACKGROUND: In women with a family history of breast cancer, bilateral prophylactic mastectomy is associated with a decreased risk of subsequent breast cancer of approximately 90%. We examined the association between bilateral prophylactic mastectomy and breast cancer risk in women at high risk for breast cancer who also had mutations in BRCA1 and BRCA2 genes. METHODS: We obtained blood samples from 176 of the 214 high-risk women who participated in our previous retrospective cohort study of bilateral prophylactic mastectomy. We used conformation-sensitive gel electrophoresis and direct sequence analysis of the blood specimens to identify women with mutations in BRCA1 and BRCA2. The carriers' probabilities of developing breast cancer were estimated from two different penetrance models. RESULTS: We identified 26 women with an alteration in BRCA1 or BRCA2. Eighteen of the mutations were considered to be deleterious and eight to be of uncertain clinical significance. None of the 26 women has developed breast cancer after a median of 13.4 years of follow-up (range, 5.8-28.5 years). Three of the 214 women are known to have developed a breast cancer after prophylactic mastectomy. For two of these women, BRCA1 and BRCA2 screening was negative, and no blood specimen was available for the third. Estimations of the effectiveness of prophylactic mastectomy were performed, considering this woman as both a mutation carrier and a noncarrier. These calculations predicted that six to nine breast cancers should have developed among the mutation carriers, which translates into a risk reduction, after bilateral prophylactic mastectomy, of 89.5%-100% (95% confidence interval = 41.4% to 100%). CONCLUSIONS: Prophylactic mastectomy is associated with a substantial reduction in the incidence of subsequent breast cancer not only in women identified as being at high risk on the basis of a family history of breast cancer but also in known BRCA1 or BRCA2 mutation carriers.

Phase I and immunomodulatory study of a muramyl peptide, muramyl tripeptide phosphatidylethanolamine.

Muramyl tripeptide phosphatidylethanolamine (MTP-PE; CGP 19835A from Ciba Geigy) is a synthetic muramyl tripeptide structurally related to bacterial cell wall constituents. MTP-PE activates monocytes in vitro to a tumoricidal state and has in vivo antitumor effects in animal models. We studied the toxicity and immunomodulatory effects of once weekly i.v. administration of liposomal-encapsulated MTP-PE for 8 weeks in 27 patients with advanced malignancies. Doses ranged from 0.1 to 2.7 mg/m2. No major tumor responses were seen; 11 patients had stable disease after 8 weeks of therapy and 3 continued on maintenance therapy because of minor tumor regressions and/or clinical improvement. MTP-PE at these doses was well tolerated. Shaking chills and fevers were the most common toxicities and occurred at all dose levels. There was no treatment-induced loss of performance status. Immunomodulatory studies revealed evidence of a biological effect on monocytes. C-reactive protein levels rose in the majority of patients with end-of-treatment values 2 to 10 times higher than baseline. Serum neopterin levels were consistently increased 24 h after MTP-PE administration and significant decreases in expression of two different types of Fc receptors on peripheral blood monocytes were noted 6 h after treatment. Although no major tumor responses were seen in this group of patients with advanced malignancies, MTP-PE was well tolerated and exerted biological effects on monocytes. Serum neopterin levels may be a useful marker for the biological effects of MTP-PE.

Comparison of loss of heterozygosity patterns in invasive low-grade and high-grade epithelial ovarian carcinomas.

Loss of heterozygosity (LOH) studies were performed to investigate the genetic differences which separate low-grade (LG), high-grade (HG), and borderline epithelial ovarian carcinomas. Fresh tumor samples and blood were obtained from 58 patients (20 LG, 34 HG, and 4 borderline tumor specimens) undergoing surgery for ovarian carcinoma at Mayo Clinic. Tumors were graded using a modified Broder's classification with invasive grades 1 and 2 considered LG, invasive grades 3 and 4 considered HG, and tumors with no evidence of stromal invasion classified as borderline. Polymorphism analysis was performed using 76 restriction fragment length polymorphisms and variable number of tandem repeats and 59 microsatellite markers representing all chromosome arms. Chromosome arms 6p, 17p, 17q, and 22q were found to be frequently lost in LG as well as HG tumors. Chromosome arms 13q and 15q were lost to a significantly greater extent in HG tumors compared to LG neoplasms (P = 0.003 and P = 0.08, respectively). Conversely, 3p loss was seen more frequently with LG tumors (P = 0.02). The majority of LG tumors (65%) did not show frequent LOH in the allelotype analysis. In fact, a subset of 7 (7 of 20) LG tumors accounted for 76% of the total allelic loss in the LG category. These tumors showed LOH almost identical to that of the HG neoplasms. Borderline tumors showed a low rate of allelic loss. There were no common events found between borderline and invasive tumors. Our data suggest that most HG tumors and a subset of LG tumors share genetic alterations at putative tumor suppressor genes detected by LOH studies. Chromosome 6 and 17 losses appear to be early events while 13q and 15q losses appear to be critical late events. However, a majority of LG tumors appear to develop as a consequence of an alternative mechanism(s) which is not detected by LOH studies. Possibilities include: (a) inactivation of tumor suppressor genes without LOH; (b) dominant negative gene(s) in which only one allele requires mutation; and (c) changes in dominant acting oncogenes. This unidentified phenomenon may be operative in borderline tumors as well.

Human epithelial ovarian cancer allelotype.

To determine which chromosomes and chromosomal regions contain putative tumor suppressor genes important for human epithelial ovarian cancer, we performed loss of heterozygosity (LOH) studies on 37 primary epithelial ovarian tumors. Using 70 polymorphic markers, we examined all chromosome arms (excluding acrocentric arms) on all specimens. Our findings show a high frequency of LOH for the following chromosome arms: 5q (43%); 6p (62%); 6q (57%); 7p (36%); 8p (40%); 9q (54%); 13q (56%); 14q (47%); 15q (36%); 17p (81%); 17q (76%); 18q (43%); 21q (36%); and 22q (71%). When separated into low and high grade tumors, there were statistically significant differences of LOH for the following chromosome arms: 6p (29% versus 70%); 13q (0% versus 72%); 17p (33% versus 90%); and 17q (29% versus 87%). No statistically significant difference was found between different histological subtypes. The average fractional allelic loss for low grade tumors was 0.17 versus 0.40 for high grade and 0.35 for all tumors. In an effort to more specifically localize common regions of molecular genetic deletion, we examined the following chromosomes in greater detail: chromosome 13 (5 markers); chromosome 17 (8 markers); and chromosome 6 (8 polymorphic markers). No tumor showed deletion of only a portion of chromosome 13. When any informative marker for chromosome 13 showed loss, all markers showed loss. Similarly, the tumors of most patients demonstrated LOH of all informative markers that map to chromosome 17; however, regional deletion of 17p markers was observed in 3 tumors. Twelve tumors demonstrated regional deletions of portions of chromosome 6. These tumors suggest that at least 2 regions of chromosome 6 are important for ovarian epithelial carcinogenesis. One region appears to be on distal 6q and a second region is near the centromere of chromosome 6 proximal to the HLA locus.