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Biomedical subjects

W M Stadler

Publications and source records attributed to W M Stadler.

At least 55 records · Page 3Linked to original sources
PubMed1998

Study of cohort-specific consent and patient control in phase I cancer trials.

PURPOSE: To address the challenging ethical dilemmas created from the participation of advanced cancer patients in phase I trials, we assessed the feasibility of a clinical trial design that uses an interactive informed consent process in which patient-subjects can choose to become directly involved in decisions of dose escalation. PATIENTS AND METHODS: Subjects were advanced cancer patients in the Hematology/Oncology Clinics at the University of Chicago who were eligible to participate in a phase I trial in which they underwent a three-step informed consent process that used cohort-specific consent and allowed them the option to choose their own doses of the chemotherapeutic agents under study, vinorelbine (NVB) and paclitaxel (TAX), within predetermined limits. NVB and TAX were administered in conventional 21- to 28-day cycles for two cycles while on study. Dose escalation occurred when a patient-subject chose a higher untested dose after they received information on all previously assessable patient-subjects. In addition to the phase I trial itself, a survey that consisted of structured interviews, which sought to evaluate patients' experiences with the interactive subject-choice phase I trial design and consent process, was conducted with participating subjects. The phase I trial itself sought to determine the associated toxicities of the agents under study. The survey results were compared with a similar survey of a matched control population of subjects who participated in other concurrently active conventional phase I trials at our institution. RESULTS: Twenty-nine patient-subjects participated in the phase I trial, with 24 who agreed to and completed the survey interviews. Seventy-six percent of patient-subjects opted to choose their dose of the agents under study, and 28% chose the highest available doses. More than half of the patient-subjects (56%) felt some degree of comfort in being asked to choose their dose of chemotherapy, with 53% stating that being asked to choose their dose made them feel in control, fully informed, or content. However, there were no statistically significant improvements in objective measures of the informed consent process, which included surveyed subjects' stated understanding of either provided information about phase I trials and alternatives to trial participation or of the research purpose of phase I trials. By making choices, the group of patients in the interactive subject choice trial changed the size of the dose cohorts and modified the process of dose escalation in this phase I study. CONCLUSION: Although complex, our innovative phase I trial design is feasible. In addition to the use of cohort-specific consent, the trial design may reduce the magnitude of many of the commonly recognized ethical dilemmas associated with this form of clinical research, which include difficulties with information provision and the understanding of possible risks and benefits of phase I trial participation, through direct subject involvement in research decision making by otherwise potentially vulnerable cancer patients.

Adult↗
PubMed1998

Expression of bcl-2 and bcl-X in bladder cancer.

PURPOSE: TP53 and RB1 gene mutations in bladder transitional cell carcinoma (TCC) are correlated with grade, stage, recurrence, and survival and may correlate with tumor cell apoptotic potential. Overexpression of the bcl-2 and bcl-X anti-apoptotic genes has been correlated with poor prognosis and chemotherapy resistance in other systems. Similar studies have not been performed in TCC. We thus sought to determine expression of bcl-2 and bcl-X in TCC and correlate these with stage, survival and abnormal pRb or p53 expression. MATERIALS AND METHODS: Forty-two TCC samples (19 Ta and 23 locally advanced tumors) and normal urothelial controls were examined. Immunohistochemistry for p53, pRb, bcl-2 and bcl-X was performed on an automated system using indirect streptavidin biotin/horseradish peroxidase staining. Western immunoblot analysis was performed on bladder cancer cell lines to further characterize bcl-X expression. Recurrence-free and disease-specific survival were retrospectively determined. Kaplan-Meier survival curves were compared using the log rank test, and correlation of abnormal staining with stage and p53 or pRb status was determined using Fisher's exact test. RESULTS: Bcl-2 was expressed in less than 1% of normal urothelial cells, but moderate expression of bcl-x was found in all normal urothelial samples. Only 7.0% of TCC samples (1/19 Ta and 2/23 locally advanced tumors) demonstrated bcl-2 overexpression. Bcl-X overexpression was observed in 45.2% of TCC (8/19 Ta and 11/23 locally advanced tumors). Western blot analysis also revealed that both the long (29 kDa) anti-apoptotic form and short (19 kDa) pro-apoptotic form were overexpressed in bladder cancer cell lines and normal human urothelial cells. Bcl-X overexpression was weakly correlated with normal p53 expression (p = 0.06). There were no correlations of bcl-2 and bcl-X overexpression with abnormal p53, pRb, or tumor stage. There were no differences in recurrence-free or overall survival in patients with abnormal bcl-X staining. CONCLUSIONS: Bcl-2 overexpression is rare in TCC. Bcl-X overexpression is common, likely reflecting its expression pattern in normal urothelium, but is not correlated with stage or abnormal p53 or pRb staining. Within the power limitations of this small study, bcl-X overexpression is not correlated with recurrence or survival.

Adult↗
PubMed1998

New chemotherapy regimens for advanced bladder cancer.

Because of demonstrated superiority in multiple randomized trials, MVAC has become the standard therapy for metastatic or unresectable bladder cancer. However, the disappointing long-term results with this regimen have prompted the development of newer agents and regimens for this disease. These include novel antifolates, gemcitabine, taxanes, ifosfamide, and gallium nitrate. Each of these agents leads to objective responses, including complete responses in both untreated and previously treated patients. More recent reports of combination regimens using these agents suggest that response rates are equivalent to those seen with MVAC but that there is significantly less toxicity. These observations, if confirmed in randomized trials, would signify an important advance in the therapy of metastatic bladder cancer.

Antimetabolites, Antineoplastic↗
PubMed1998

Phase II and pharmacodynamic studies of pyrazine diazohydroxide (NSC 361456) in patients with advanced renal and colorectal cancer.

Pyrazine diazohydroxide (PZDH) is a novel antitumor agent that forms DNA adducts via the reactive pyrazine diazonium ion. In a recent Phase I study of PZDH, we identified a recommended Phase II dose of 100 mg/m2/day x 5, given as a 5-min i.v. bolus with the cycles repeated every 42 days (N. J. Vogelzang, et al, Cancer Res., 54: 114-119, 1994). There was a moderate negative correlation between serum chloride concentration and logarithm platelet nadir, suggesting the hypothesis that PZDH is activated in an acidic environment, leading to more toxicity in acidotic patients. Therefore, the University of Chicago Phase II cooperative network conducted two Phase II studies of PZDH in renal cancer (15 patients, 2 with liver metastases) and in 5-fluorouracil-refractory colorectal cancer (14 patients, 13 with liver metastases) to determine efficacy in each disease and to correlate safety and tolerance of the drug with PZDH pharmacokinetics/pharmacodynamics and with arterial blood gas measurements. There were no responses seen in either tumor type. The primary toxicity of PZDH was myelosuppression with neutropenia (absolute neutrophil count, < 1000/microl) and thrombocytopenia (<50,000 cells/microl), seen in 41 and 24% of all cycles, respectively. Other grade 3 and 4 toxicities were rare. Pharmacodynamic analysis revealed no significant correlation between plasma levels at 5, 60, and 120 min; WBCs; absolute neutrophil and platelet count nadirs; and initial serum chloride or blood pH levels. The colorectal patients experienced significantly more thrombocytopenia than did the renal cancer patients (median platelet nadir after cycle 1 was 151 x 10(3)/microl for renal patients versus 76 x 10(3)/microl for colon patients; P = 0.04), suggesting either that prior 5-fluorouracil and leucovorin reduced bone marrow reserve or that colorectal patients with liver metastases experienced more PZDH toxicity. Regression analyses revealed a possible relationship (P = 0.06) between serum pH and thrombocytopenia (i.e., for each increase of 0.03 in pH, there was a 34% increase in the platelet nadir), but there was no relationship between serum chloride and thrombocytopenia. Curiously, an increase in alkaline phosphatase was associated with an increase in the platelet nadir (P = 0.02). If PZDH continues to be developed as an antineoplastic agent, further studies of these relationships are suggested.

Adult↗
PubMed1998

Activated calphostin C cytotoxicity is independent of p53 status and in vivo metastatic potential.

The development of novel therapeutic agents to modulate programmed cell death independent of genetic background or malignant potential is a primary goal of modern cancer therapy. In this report, the light activation- and concentration-dependent cytotoxicity of calphostin C, a photoactivatable perylenequinone, is carefully evaluated using a series of nine well-characterized human and rodent prostate cancer cell lines representing the spectrum of disease progression (e.g., variations in metastatic ability, ploidy, and tumor suppressor gene status). Treatment of these cancer cell lines with nanomolar concentrations of calphostin C in combination with increasing amounts of light exposure established a relationship between light and dose dependence of calphostin C cytotoxicity. The induction of apoptosis is rapid, as evidenced by the fact that immediately after treatment, cells exposed to calphostin C with light activation exhibit both morphological and biochemical changes consistent with apoptosis (cellular and nuclear shrinkage and chromatin condensation). For example, 78% of cells treated with 100 nM calphostin C in combination with 2 h of light activation underwent apoptosis within 24 h of treatment. DNA ladder formation could be detected within 12 h of treatment. In the absence of light activation, treatment with calphostin C at all concentrations tested had no acute or durable cytotoxic effects in any of the cell lines. Our findings demonstrate that calphostin C cytotoxicity is strictly light dependent. Furthermore, its efficacy is independent of the genetic background, p53 status, or in vivo malignant potential of a cell, making it a suitable candidate for the treatment of heterogeneous tumor cell populations.

Animals↗
PubMed1997

Loss of the CDKN2A/p16 locus detected in bladder irrigation specimens by fluorescence in situ hybridization.

PURPOSE: We measured the CDKN2A/p16 tumor suppressor gene locus in bladder irrigation specimens and correlated the measurement with the clinical status of patients with bladder cancer. MATERIALS AND METHODS: Irrigation specimens were obtained at cystoscopy from 10 normal controls, 21 patients with bladder cancer in whom no concurrent bladder tumor was seen and 23 patients with bladder tumors. Deoxyribonucleic cytometry and fluorescence in situ hybridization measurements were made. One fluorescence in situ hybridization probe was specific to the chromosome 9 centromere and the other, COSp16, targeted the CDKN2A/p16 region on chromosome 9p21. Three rates were calculated, including the hyperdiploid fraction from deoxyribonucleic acid cytometry, disomic fraction from the 9 centromere count and COSp16F, the frequency of COSp16 in association with 9 centromere. Specimens were classified as positive or negative for each of these rates using cutoff points based on previous studies and the distribution of values obtained for the normal control specimens. RESULTS: Hyperdiploid fraction values were positive (greater than 8%) in 1 normal and 1 nontumor specimen. Ten specimens from patients with tumor showed elevated hyperdiploid fraction values. In 4 nontumor and 13 tumor irrigation specimens the chromosome 9 disomic fraction values were positive (less than 80%). COSp16F was positive (less than 83%) for 18 nontumor irrigation specimens and 18 tumor irrigation specimens. One normal, and 39 of 44 nontumor and tumor irrigation specimens were positive by at least 1 test. CONCLUSIONS: COSp16 loss is measurable in irrigation specimens and it correlates with clinical status. This assay may prove useful in screening for and managing bladder cancer.

DNA, Neoplasm↗
PubMed1997

Metastatic bladder cancer: advances in treatment.

At present, a combination of cisplatin, methotrexate, vinblastine and doxorubicin is the most widely used chemotherapy for metastatic bladder cancer. However, long-term follow-up shows that this combination may have little effect on survival. In addition, this regimen is toxic. New agents are needed which combine efficacy with good safety profiles. Agents which have been investigated include gallium nitrate, interferon-alpha and paclitaxel both as single agents and in combination with established cytotoxic drugs. A number of studies have been conducted in bladder cancer with the novel nucleoside analogue, gemcitabine. Response rates of up to 33% have been recorded in two phase II studies. Gemcitabine was well tolerated in both studies with few of the side-effects normally associated with cytotoxic drugs. A third study is ongoing.

Adult↗
PubMed1997

Phase II study of single-agent gemcitabine in previously untreated patients with metastatic urothelial cancer.

PURPOSE: To determine the activity of single-agent gemcitabine in previously untreated patients with metastatic transitional cell cancer. METHODS: Forty patients with measurable disease and a Karnofsky performance status > or = 60% were enrolled at five institutions between March 1994 and October 1995. Treatment consisted of gemcitabine (1,200 mg/m2) administered weekly times three on a 4-week cycle. One patient was ineligible for response evaluation because pathology review showed a metastatic melanoma. Responses were confirmed by all investigators and an independent radiologist and were maintained for at least 4 weeks. RESULTS: There were four complete and seven partial responses, for an overall response rate of 28%. Responses were seen at all sites, including liver. Median progression-free and overall survival times were 20 and 54 weeks, respectively. Toxicity was mild, with only two grade 4 toxicities. Twenty-five percent of patients experienced grade 3 neutropenia or thrombocytopenia that was rapidly reversible. CONCLUSION: Gemcitabine exhibits significant activity in metastatic transitional cell cancer with minimal toxicity, but survival remains short. Trials of gemcitabine in combination with other active agents are thus suggested.

Adult↗
PubMed1996

Elevated p16 at senescence and loss of p16 at immortalization in human papillomavirus 16 E6, but not E7, transformed human uroepithelial cells.

CDKN2/p16 inhibits the cyclin D/cyclin-dependent kinase complexes that phosphorylate pRb, thus blocking cell cycle progression. We previously reported that p16 levels are low to undetectable in normal human uroepithelial cells (HUCs) and in immortalized uroepithelial cells with functional pRb, whereas p16 levels are markedly elevated in immortal HUCs with altered pRb (T. Yeager et al., Cancer Res., 55: 493-497, 1995). We now report that elevation of p16 levels occurs at senescence in HUCs, including HUCs transformed by human papillomavirus 16 E7 or E6, whose oncoprotein products lead to functional loss of pRb and p53, respectively. We also report that six of six independently immortalized E7 HUCs show high levels of p16 similar to those observed at HUC senescence, whereas p16 is undetectable in five of five immortal E6 HUCs. Four of the five independent E6 HUCs that lost p16 at immortalization showed hemizygous deletion of the 9p21 region. However, no homozygous CDKN2 deletions were detected, and only one CDKN2 mutation was identified. For the first time, these data associate elevated p16 with senescence in human epithelial cells. These data also suggest that a component of immortalization may be abrogation, either by pRb inactivation (as in the E7-transformed HUCs) or by p16 inactivation (as in the E6-transformed HUCs), of a p16-mediated senescence cell cycle block.

Carrier Proteins↗
PubMed1996

The 9p21 region in bladder cancer cell lines: large homozygous deletion inactivate the CDKN2, CDKN2B and MTAP genes.

Homozygous and hemizygous deletions of 9p21 are the earliest and most common genetic alteration in bladder cancer. The identification of two cell cycle regulators, CDKN2 and CDKN2B, that map to the common region of deletion has prompted the hypothesis that they are critical tumor suppressor genes in this malignancy. However, controversy as to whether these genes are the only or even the most important target in bladder cancer oncogenesis remains. To more clearly determine the effect of these 9p21 alterations, we mapped the homozygous deletions and performed a detailed mutational and expression analysis for CDKN2, CDKN2B and a closely linked gene, methylthioadenoside phosphorylase (MTAP), in 16 established bladder cancer cell lines. Nine of the 16 lines exhibit large (30 to > 2000 kb) homozygous deletions on 9p21. All deletions include at least one exon of CDKN2, eight of nine include CDKN2B, and six of nine include MTAP. MTAP function correlates with the genomic deletions. SSCP and sequence analysis does not reveal any inactivating point mutations of CDKN2 or of CDKN2B in any of the cell lines without homozygous deletions, and all express the CDKN2 and the CDKN2B mRNA as well as the encoded p16 protein. The p16 protein levels vary widely and are correlated with absent pRb expression. We conclude that the 9p21 deletions in bladder cancer usually inactivate the CDKN2. CDKN2B, and MTAP genes but that CDKN2 is the most common target. Other mechanisms for inactivating this gene in bladder cancer appear to be uncommon.

Carrier Proteins↗
PubMed1996

High-dose continuous intravenous infusion of interleukin-2 therapy for metastatic renal cell carcinoma: the University of Chicago experience.

OBJECTIVES: Treatment of patients with metastatic renal cell carcinoma with high-dose interleukin-2 (IL-2) administered as continuous intravenous (CIV) infusion or as bolus injection results in response rates of 15% to 30%; however, toxicities with these regimens have been severe. A trial in which CIV IL-2 was administered at high doses during days 1 to 5 and at reduced doses during days 10 to 20 reported less toxicity without a decrease in response rates. We treated a series of patients with this regimen and our experience is presented. METHODS: Seventeen patients with metastatic renal cell carcinoma were treated with IL-2 by CIV at a dose of 18 x 10(6) IU/m2/day for 5 days followed by 4 to 6 days of rest followed by 10 days of CIV IL-2 at a dose of 6 x 10(6) IU/m2/day. Five patients also received CT-1501R, a pentoxifylline derivative. RESULTS: There was 1 partial responder (PR) and there were no complete responses. The patient with the PR had a 14 x 9 cm(2) renal tumor with metastases to lung, pancreas, and liver. A surgical resection induced a CR, but he relapsed 9 months later. Severe toxicities included hyponatremia (serum sodium of less than 123 mmol/L) (n=3), biopsy-proven cardiomyopathy (n=1), creatinine more than 4.5 mg/dL (n=7), and sudden death (n=1). CONCLUSIONS: We conclude that high-dose CIV IL-2 therapy of renal cell carcinoma results in severe toxicity and cannot be recommended for general use. Alternatives need to be developed.

Adjuvants, Immunologic↗
PubMed1996

Use of a new tumor marker, urinary NMP22, in the detection of occult or rapidly recurring transitional cell carcinoma of the urinary tract following surgical treatment.

PURPOSE: We evaluated the ability of an immunoassay for nuclear matrix protein 22 (NMP22 test kit) to predict the subsequent disease status of patients with transitional cell carcinoma of the urinary tract at approximately 10 days after transurethral resection of bladder tumor. MATERIALS AND METHODS: A total of 90 patients with transitional cell carcinoma provided voided urine samples at least 5 days postoperatively. NMP22 was determined using a commercial test kit. At initial cystoscopic examination 3 to 6 months later the disease status was recorded, and the NMP22 values before and after transurethral resection of bladder tumor were compared. RESULTS: Of 125 followup cystoscopic examinations (60 patients had 1, 26 had 2, 3 had 3 and 1 had 4 recurrences) transitional cell carcinoma was pathologically confirmed in 33. No malignancy was present at 79 examinations (if tumor was seen endoscopically, pathological evaluation indicated atypia, dysplasia or no abnormality). NMP22 values in these 2 populations were significantly different (malignancy median 20.81 units per ml. and no malignancy median 5.72 units per ml., Mann-Whitney U test for differences between 2 medians p = 0.00005). Of the 33 recurrences 23 (70%) had NMP22 values greater than the reference range (10 units per ml.). Additionally, NMP22 identified all 6 subjects (100%) who had invasive disease 3 to 6 months later. Of 72 patients with NMP22 less than 10 units per ml. 62 (86%) had no malignancy at subsequent cystoscopy. CONCLUSIONS: NMP22 was highly predictive of tumor status at followup cystoscopy. This quantitative, noninvasive assay, with high negative predictive value (86%) and sensitivity to detect malignancy (100% for invasive disease and 70% overall), may be a helpful adjunct to cytology and endoscopy for monitoring disease status after endoscopic tumor resection.

Biomarkers, Tumor↗
PubMed1996

Urinary nuclear matrix protein as a marker for transitional cell carcinoma of the urinary tract.

PURPOSE: The purpose of this trial was to evaluate an immunoassay for urinary nuclear matrix protein, NMP22, as an indicator for transitional cell carcinoma of the urinary tract. MATERIALS AND METHODS: Three groups of subjects participated in this trial of NMP22: 1-175 with transitional cell carcinoma, 2-117 with benign urinary tract conditions and 3-375 healthy volunteers. Each subject provided a single (3 voids) urine sample for analysis at the time of study entry. Each sample was assayed for the level of NMP22. RESULTS: In normal healthy volunteers and in subjects with benign conditions median NMP22 levels were 2.9 and 3.3 units per ml., respectively. Median urinary NMP22 levels in patients with transitional cell carcinoma were significantly greater than in comparison subjects. Patients with active transitional cell carcinoma had significantly greater median urinary NMP22 levels than those with no evidence of disease (6.04 versus 4.11 units per ml., p = 0.027, 1-tailed Mann-Whitney U test). We noted no effect of tumor grade, extent of disease or exposure to intravesical therapy on urinary NMP22 levels. CONCLUSIONS: NMP22 is a promising urinary tumor marker for monitoring transitional cell carcinoma. Nuclear matrix proteins are a new class of tumor markers that represent the basis for the development of assays with increased efficacy for the detection and treatment of cancer.

Aged↗
PubMed1995

A phase II study of subcutaneous recombinant human interleukin-4 in metastatic renal cell carcinoma.

BACKGROUND: A study was conducted to assess the response rate for and toxicity of recombinant human interleukin-4 (IL-4) administered subcutaneously to outpatients with metastatic renal cell cancer. METHODS: Human recombinant IL-4 provided by Schering-Plough Research Corporation was administered subcutaneously to 19 patients at a dose of 1 microgram/kg three times per week. Eligibility included Cancer and Leukemia Group B performance status of 2 or better, adequate hematologic (leukocyte count < or = 2500/microliters platelets < or = 75,000/microliters), renal (creatinine < or = 2.0 mg/dl), and hepatic (serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, and alkaline phosphatase < or = 3 times the upper limit of normal) function. Exclusion criteria included prior immunotherapy, clinically significant diabetes, pulmonary disease, and history of congestive heart failure or an ejection fraction of less than 40%. Soluble CD23 was measured in prospectively collected serum via an enzyme-linked immunosorbent assay technique. RESULTS: There was one minor response among 18 evaluable patients and median survival was only 35 weeks. Toxicities included fever, fatigue, myalgias, arthralgias, nausea, and anorexia. One patient each experienced a 14% asymptomatic decrease in the cardiac ejection fraction, a gastrointestinal bleed, and oral angioedema. Ten patients noted increased pain in tumor bearing areas, especially in areas of bony disease. Two patients with pre-existing vertebral disease experienced symptoms of cord compression. In 12 patients for whom complete data were available there was a mean increase in soluble CD23 of 2.6 ng/ml (P = 0.002) 1-2 weeks after therapy initiation. CONCLUSIONS: At this modest dose and schedule, IL-4 was tolerated in most patients. There was minimal biologic and clinical activity. Further development of IL-4 as a therapeutic agent in metastatic renal cell cancer at this dose and schedule is not supported by this study.

Adult↗
PubMed1995

Construction of a 2.8-megabase yeast artificial chromosome contig and cloning of the human methylthioadenosine phosphorylase gene from the tumor suppressor region on 9p21.

Many human malignant cells lack methylthioadenosine phosphorylase (MTAP) enzyme activity. The gene (MTAP) encoding this enzyme was previously mapped to the short arm of chromosome 9, band p21-22, a region that is frequently deleted in multiple tumor types. To clone candidate tumor suppressor genes from the deleted region on 9p21-22, we have constructed a long-range physical map of 2.8 megabases for 9p21 by using overlapping yeast artificial chromosome and cosmid clones. This map includes the type IIFN gene cluster, the recently identified candidate tumor suppressor genes CDKN2 (p16INK4A) and CDKN2B (p15INK4B), and several CpG islands. In addition, we have identified other transcription units within the yeast artificial chromosome contig. Sequence analysis of a 2.5-kb cDNA clone isolated from a CpG island that maps between the IFN genes and CDKN2 reveals a predicted open reading frame of 283 amino acids followed by 1302 nucleotides of 3' untranslated sequence. This gene is evolutionarily conserved and shows significant amino acid homologies to mouse and human purine nucleoside phosphorylases and to a hypothetical 25.8-kDa protein in the pet gene (coding for cytochrome bc1 complex) region of Rhodospirillum rubrum. The location, expression pattern, and nucleotide sequence of this gene suggest that it codes for the MTAP enzyme.

Amino Acid Sequence↗
PubMed1994

Homozygous deletions within chromosomal bands 9p21-22 in bladder cancer.

The loss of DNA sequences on chromosomal bands 9p21-22 has been documented in a variety of malignancies including leukemias, gliomas, lung cancers, and melanomas. Because of the high incidence of monosomy 9 detected by both cytogenetics and loss of heterozygosity studies in bladder cancer, we examined seven bladder cancer cell lines for deletions in this region. Using seven DNA probes that span the region of 9p21-22 as well as a functional assay for methylthioadenosine phosphorylase (MTAP), which maps to 9p21, we found four cell lines that had small homozygous deletions. These deletions map centromeric to the interferon (IFN) gene cluster and telomeric to D9S171. Only one of the cell lines with deletions had a cytogenetically evident lesion in this chromosomal region. Preliminary loss of heterozygosity studies with 10 primary bladder cancer specimens using 10 markers spanning chromosome 9 revealed loss of heterozygosity at the IFN locus with retention of heterozygosity with more centromeric 9p markers and all informative 9q markers in the tumor of one patient. These data suggest that loss of a tumor suppressor gene on 9p21-22, which may represent a general pathway of oncogenesis, is important in bladder cancer development.

Blotting, Southern↗