PubMed Health⌕ Search

Biomedical subjects

T J Polascik

Publications and source records attributed to T J Polascik.

At least 19 recordsLinked to original sources
PubMed2006

Salvage prostate cryoablation after primary interstitial brachytherapy failure: a feasible approach.

Salvage treatment for recurrent prostate cancer remains a very difficult and challenging field in urologic oncology. The introduction of minimally invasive surgical procedures such a targeted cryoablation brings some hope with its feasibility and efficacy to become a potentially curable treatment. We present the case of a 75-year-old male with prostate cancer treated primarily by brachytherapy, who developed late locally recurrent disease that was successfully treated with targeted salvage cryoablation.

Aged↗
PubMed2001

Synthesis and evaluation of 18F-labeled choline as an oncologic tracer for positron emission tomography: initial findings in prostate cancer.

The up-regulation of rates of choline uptake and phosphorylation in certain malignancies has motivated the development of positron-labeled choline analogues for noninvasive detection of cancer using positron emission tomography (PET). The choline analogue, no-carrier-added [18F]fluoromethyl-dimethyl-2-hydroxyethyl-ammonium (FCH), was synthesized through the intermediate [18F]fluorobromomethane. FCH was evaluated in relationship to 2-[18F]fluoro-2-deoxyglucose (FDG) as an oncological probe in cultured PC-3 human prostate cancer cells, a murine PC-3 human prostate cancer xenograft model, and in PET imaging studies of patients with prostate cancer. FCH was synthesized in 20-40% radiochemical yield and >98% radiochemical purity. Accumulation of FCH and FDG were comparable in cultured prostate cancer cells, whereas only FCH was inhibited (90%) by hemicholinium-3, a specific inhibitor of choline transport and phosphorylation. FCH showed similar biodistribution to [14C]choline in the tumor-bearing mouse, with prominent renal and hepatic uptake. Tumor uptake of FCH was similar to choline and FDG in the mouse model, although tumor:blood ratios were moderately higher for FCH. Initial PET imaging studies in prostate cancer patients showed high uptake of FCH in advanced prostate carcinoma and detection of osseous and soft tissue metastases. FCH uptake by tumors was markedly reduced in patients rescanned during androgen deprivation therapy. It is concluded that FCH closely mimics choline uptake by normal tissues and prostate cancer neoplasms. FCH is potentially useful as a PET tracer for detection and localization of prostate cancer and monitoring effects of therapy.

Aged↗
PubMed2001

Management of small renal tumors: an overview.

The incidental finding of a small renal mass poses a therapeutic dilemma. The traditional treatment of clinically important masses has been radical nephrectomy. Recently, nephron-sparing surgery has emerged as a viable alternative; and experimental minimally invasive percutaneous tissue ablation techniques, including cryotherapy and radiofrequency ablation, are being evaluated. In this review, we discuss the dilemma posed by frequent renal imaging and the increased proportion of incidental tumors being detected, the limitations of needle biopsies for histologic diagnosis, nephron-conserving and minimally invasive surgery, and the possible merits of radiofrequency ablation and cryotherapy. We envision a defined role for minimally invasive percutaneous or extracorporeal ablation of small renal tumors.

Carcinoma, Renal Cell↗
PubMed2001

Pilot study of dietary fat restriction and flaxseed supplementation in men with prostate cancer before surgery: exploring the effects on hormonal levels, prostate-specific antigen, and histopathologic features.

OBJECTIVES: Dietary fat and fiber affect hormonal levels and may influence cancer progression. Flaxseed is a rich source of lignan and omega-3 fatty acids and may thwart prostate cancer. The potential effects of flaxseed may be enhanced with concomitant fat restriction. We undertook a pilot study to explore whether a flaxseed-supplemented, fat-restricted diet could affect the biomarkers of prostatic neoplasia. METHODS: Twenty-five patients with prostate cancer who were awaiting prostatectomy were instructed on a low-fat (20% of kilocalories or less), flaxseed-supplemented (30 g/day) diet. The baseline and follow-up levels of prostate-specific antigen, testosterone, free androgen index, and total serum cholesterol were determined. The tumors of diet-treated patients were compared with those of historic cases (matched by age, race, prostate-specific antigen level at diagnosis, and biopsy Gleason sum) with respect to apoptosis (terminal deoxynucleotidyl transferase [TdT]-mediated dUTP-biotin nick end-labeling [TUNEL]) and proliferation (MIB-1). RESULTS: The average duration on the diet was 34 days (range 21 to 77), during which time significant decreases were observed in total serum cholesterol (201 +/- 39 mg/dL to 174 +/- 42 mg/dL), total testosterone (422 +/- 122 ng/dL to 360 +/- 128 ng/dL), and free androgen index (36.3% +/- 18.9% to 29.3% +/- 16.8%) (all P <0.05). The baseline and follow-up levels of prostate-specific antigen were 8.1 +/- 5.2 ng/mL and 8.5 +/- 7.7 ng/mL, respectively, for the entire sample (P = 0.58); however, among men with Gleason sums of 6 or less (n = 19), the PSA values were 7.1 +/- 3.9 ng/mL and 6.4 +/- 4.1 ng/mL (P = 0.10). The mean proliferation index was 7.4 +/- 7.8 for the historic controls versus 5.0 +/- 4.9 for the diet-treated patients (P = 0.05). The distribution of the apoptotic indexes differed significantly (P = 0.01) between groups, with most historic controls exhibiting TUNEL categorical scores of 0; diet-treated patients largely exhibited scores of 1. Both the proliferation rate and apoptosis were significantly associated with the number of days on the diet (P = 0.049 and P = 0.017, respectively). CONCLUSIONS: These pilot data suggest that a flaxseed-supplemented, fat-restricted diet may affect prostate cancer biology and associated biomarkers. Further study is needed to determine the benefit of this dietary regimen as either a complementary or preventive therapy.

Adult↗
PubMed2001

Utility of capromab pendetide (ProstaScint) imaging in the management of prostate cancer.

PURPOSE: Capromab pendetide (ProstaScint) is an indium In 111 ((111)In)-labeled monoclonal antibody to prostate-specific membrane antigen (PSMA) used to image prostate cancer. The appropriate techniques for obtaining images with this modality and the appropriate clinical indications for this study are in the process of being optimized. MATERIALS AND METHODS: From 1994 to 2000, 631 monoclonal antibody imaging studies with (111)In capromab pendetide were performed. The accuracy and utility of this modality in the primary staging of patients with disease at high risk of metastasis and patients with recurrent or residual disease after primary therapy were evaluated. RESULTS: In high-risk patients evaluated for risk of lymph node metastases prior to pelvic lymph node dissection, capromab pendetide imaging was found to have a positive predictive value (PPV) of 62%, negative predictive value (NPV) of 72%, sensitivity of 62%, and specificity of 72%. In patients evaluated with capromab pendetide imaging for prostatic fossa recurrence using prostatic fossa needle biopsy as the gold standard, capromab pendetide imaging was found to have a PPV of 50%, NPV of 70%, sensitivity of 49%, and specificity of 71%. CONCLUSIONS: The sensitivity and NPV of (111)In capromab pendetide imaging are better than those of computed tomography and magnetic resonance imaging for detection of soft-tissue and nodal metastases from prostate cancer. The utility of this modality has been demonstrated in the primary staging of patients with disease at high risk of metastasis. Patients with recurrent or residual disease after primary therapy also may benefit from capromab pendetide imaging prior to selection of salvage therapy. Innovative methods for the use of capromab pendetide imaging in radiation therapy treatment planning are under development.

Antibodies, Monoclonal↗
PubMed2000

Survey of neuromuscular injuries to the patient and surgeon during urologic laparoscopic surgery.

OBJECTIVES: Laparoscopy may be complicated by neuromuscular injuries, both to the patient and to the surgeon. We used a survey to estimate the incidence of these injuries during urologic laparoscopic surgery, to assess risk factors for these injuries, and to determine preventive measures. METHODS: A survey of neuromuscular injuries associated with laparoscopy submitted to 18 institutions in the United States was completed by 18 attending urologists from 15 institutions. RESULTS: From among a total of 1651 procedures, there were 46 neuromuscular injuries in 45 patients (2.7%), including abdominal wall neuralgia (14), extremity sensory deficit (12), extremity motor deficit (8), clinical rhabdomyolysis (6), shoulder contusion (4), and back spasm (2). Neuromuscular injuries were twice as common with upper retroperitoneal as with pelvic laparoscopy (3. 1% versus 1.5%). Among patients with neuromuscular injuries, those with rhabdomyolysis were heavier (means 91 versus 80 kg) and underwent longer procedures (means 379 versus 300 minutes), and those with motor deficits were older (means 51 versus 42 years of age). Of the surgeons, 28% and 17% reported frequent neck and shoulder pain, respectively. CONCLUSIONS: Although not common, neuromuscular injuries during laparoscopy do contribute to morbidity. Abdominal wall neuralgias, injuries to peripheral nerves, and joint or back injuries likely occur no more frequently than during open surgery, but risk of rhabdomyolysis may be increased. Positioning in a partial rather than full flank position may reduce the incidence of some injuries. Measures to reduce neuromuscular strain on the surgeon during laparoscopy should be considered.

Abdominal Muscles↗
PubMed2000

Capromab Pendetide imaging of prostate cancer.

Capromab Pendetide imaging illustrates the successful translation of monoclonal antibody technology from the laboratory to the clinic. It provides a means of identifying otherwise occult soft tissue metastases in patients with adenocarcinoma of the prostate. When utilized with other clinical, pathological and laboratory findings, Capromab Pendetide imaging enables more accurate disease staging and monitoring than is afforded by other imaging modalities such as CT and MRI. In the primary disease setting Capromab Pendetide imaging should be reserved for use in patients with negative bone scans who are at high risk for metastatic disease based on such factors as advanced clinical stage, high Gleason score and significantly elevated serum PSA or alkaline phosphatase. Due to low sensitivity for small-volume disease, a negative Mab scan may not eliminate the need for a staging lymph node dissection but should encourage further consideration of local treatment options. Capromab Pendetide should be used with caution in patients at low risk for metastatic disease. Positive scan findings in low risk patients should be confirmed before altering the treatment plan since some false positive scans should be anticipated in a population with low disease prevalence. Capromab Pendetide imaging has not been shown to be reliable in determining the local extent of the primary tumor but new techniques involving co-registration of SPECT and CT images show promise in this regard. In the patient with recurrent disease following primary therapy, the predictive value of Capromab Pendetide imaging of the prostate or prostate fossa is limited, particularly following RT. Its more important role in this setting is to identify lymph node metastases in the high risk patient with a negative bone scan who might otherwise be a candidate for local salvage therapy. A large prospective study is needed for confirmation, but preliminary data suggest that Capromab Pendetide imaging is helpful in identifying those patients with PSA elevation after radical prostatectomy who are most likely to benefit from salvage RT. As with any imaging technique, Capromab Pendetide has strengths and weaknesses that must be understood to maximize patient benefit by utilizing the scan in clinical settings where it is most likely to be useful and least likely to be misleading. Capromab Pendetide is a technically demanding procedure best performed and interpreted at sites with experience and expertise.

Adenocarcinoma↗
PubMed1999

Comparison of clinical staging algorithms and 111indium-capromab pendetide immunoscintigraphy in the prediction of lymph node involvement in high risk prostate carcinoma patients.

BACKGROUND: The pretherapy prediction of occult lymph node involvement and the avoidance of otherwise futile and potentially morbid definitive local therapy is paramount in men with newly diagnosed prostate carcinoma. To identify patients with prostate carcinoma who likely have lymph node involvement and would benefit from staging lymphadenectomy prior to definitive local therapy, the authors compared the ability of several predictive staging algorithms and a radiolabeled monoclonal antibody scan to predict lymphatic metastases prior to treatment. METHODS: Between August 1991 and June 1994, 198 men with clinical T2 or T3 classified (TNM) prostate carcinoma (bone scan negative) who were at high risk of lymph node involvement underwent a 111In-capromab pendetide scan prior to staging lymphadenectomy. Several predictive models based on preoperative prostate specific antigen level, biopsy Gleason score, and clinical stage were selected to predict those men having a > or =20% probability of lymph node involvement. The ability to predict pathologic stage using several clinical algorithms and the monoclonal antibody scan was compared with pathologic examination of the lymph nodes. RESULTS: Overall, 39% of the pelvic lymph node specimens were positive for metastatic disease by pathologic analysis. Published algorithms predicting lymph node metastases had a positive predictive value (PPV) ranging from 40.5% to 46.6% and an area under the receiver operating characteristic curve (AUC) ranging from 0.52 to 0.61. The monoclonal antibody scan had a PPV of 66.7% and an AUC of 0.71. The differences between the PPV and the AUC for the individual clinical algorithms when compared with immunoscintigraphy were statistically significant. Combining the radiolabeled monoclonal antibody scan with clinical predictive models, a PPV of up to 72.1% could be obtained. CONCLUSIONS: These data suggest that the PPVs for the clinical predictive algorithms are similar and that the PPV of the radiolabeled monoclonal antibody scan alone or in combination with the algorithms has additional value in predicting lymph node involvement in prostate carcinoma patients at high risk of regional disease spread. These algorithms and the 111In-capromab pendetide scan may be used for the appropriate selection of candidates for definitive local therapy in men with clinically localized prostate carcinoma and significant risk of lymph node involvement.

Aged↗
PubMed1999

Prostate specific antigen: a decade of discovery--what we have learned and where we are going.

PURPOSE: Many advances have occurred during the last decade in the clinical use of prostate specific antigen (PSA) for detecting, staging and monitoring prostate cancer. We review the clinical usefulness and limitations of serum PSA as a tumor marker of prostate cancer. MATERIALS AND METHODS: The English language literature was reviewed with respect to the major contributions and limitations of PSA in present clinical practice. RESULTS: Although controversial, age specific PSA reference ranges can improve the sensitivity for prostate cancer detection in young men and the specificity in older men. Percent free PSA improves the specificity for prostate cancer detection in men with PSA values between 4 and 10 ng./ml., and a PSA density of greater than 0.15 may better distinguish benign prostatic hyperplasia from prostate cancer. PSA velocity can improve the ability to detect prostate cancer when 3 serial PSA values are measured during a 2-year period. For prostate cancer staging PSA is most useful combined with clinical stage and Gleason score in multivariate analysis. Percent free PSA may prove useful for staging prostate cancer but further clinical trials are needed to determine its clinical usefulness. PSA is the most clinically useful means to monitor disease recurrence after treatment of prostate cancer. With ultrasensitive PSA assays it is now possible to increase the lead time for detection of disease recurrence by several months. CONCLUSIONS: During the last decade much of the focus has been on improving the ability of this tumor marker to detect prostate cancer. PSA remains the best and most widely used tumor marker in urology today.

Forecasting↗
PubMed1999

Ablation of renal tumors in a rabbit model with interstitial saline-augmented radiofrequency energy: preliminary report of a new technology.

OBJECTIVES: To evaluate the efficacy of interstitial saline radiofrequency energy for reproducibly ablating nonmalignant (control) and malignant (the VX-2 tumor) renal tissue in a rabbit model, and to determine the ability of conventional gray-scale and power sonography to image the tumor and ablative process in real time before, during, and after treatment. METHODS: The VX-2 tumor was implanted beneath the renal capsule in 18 rabbit kidneys. Twelve days after implantation, 50 W of 500-kHz radiofrequency energy was delivered into the surgically externalized renal tumor and contralateral control kidney for 30 or 45-second treatment intervals using an interstitial saline-augmented radiofrequency probe (the virtual electrode). Localization of the tumor and response to treatment were imaged with gray-scale and power Doppler ultrasonography. The effect of radiofrequency and extent of the destructive process on benign and malignant renal tissue were evaluated histologically. RESULTS: Mean tumor size was 1.3 x 0.7 cm. Both 30 and 45-second treatment intervals provided marked tissue/tumor ablation. Gross anatomic and histologic analysis showed time-dependent ablated lesions averaging 1.4+/-0.3 x 1.0+/-0.3 cm (30-second treatment) and 1.8+/-0.4 x 1.5+/-0.3 cm (45-second treatment), with clear demarcation of the surrounding parenchyma. Conventional gray-scale sonography allowed visualization of the ablative process, and power Doppler ultrasound demonstrated changes in the vascular pattern of the tumor both before and after ablation. No immediate treatment-related complications were observed. CONCLUSIONS: These preliminary studies in a rabbit model demonstrate the feasibility of using the interstitial saline-augmented electrode to ablate small renal tumors and the ability to simultaneously visualize the ablative process using real-time ultrasonography. This technology may have the potential to treat small renal tumors in a minimally invasive manner in the clinical setting.

Animals↗
PubMed1999

Influence of sextant prostate needle biopsy or surgery on the detection and harvest of intact circulating prostate cancer cells.

PURPOSE: The feasibility of harvesting intact, circulating prostate cancer cells from the blood of men with advanced prostate cancer has previously been demonstrated. We studied the influence of sextant prostate needle biopsy and radical prostatectomy on harvesting intact circulating prostate cancer cells. MATERIALS AND METHODS: Via standard venipuncture 20 c.c. blood were obtained preoperatively, and 30 minutes and 3 days postoperatively from 23 men with clinically localized prostate cancer undergoing surgery. Similarly, blood was obtained before and after routine prostate biopsy from 13 men for an elevated prostate specific antigen level and/or abnormal digital rectal examination. The blood cells were removed via density centrifugation and magnetic cell sorting. The remaining prostate epithelial cells were characterized by indirect fluorescent immunocytochemical staining and fluorescent in situ hybridization using deoxyribonucleic acid probes. RESULTS: Sextant biopsy of the prostate induced circulating cells in 3 of 13 men (23%), only 1 of whom demonstrated cells with aneuploidy (Gleason score 3+4 = 7). Circulating cells were detected preoperatively, 30 minutes or 3 days postoperatively in 35% of radical prostatectomy cases. Of the patients 13% had detectable circulating cells 30 minutes postoperatively only and 9% had cells harvested on postoperative day 3. Persistence of circulating prostate cancer cells was noted in 13% of men on postoperative day 3. Serum prostate specific antigen level and pathological stage did not appear to be related to harvested cell number. CONCLUSIONS: Prostate cancer cells can be harvested from men with clinically localized disease undergoing sextant needle biopsy or radical prostatectomy. Routine prostate biopsy and surgery may influence the number of measurable circulating cells in the short term but the clinical significance and long-term prevalence of detectable circulating cells are unknown. Further studies are needed to evaluate the clinical usefulness of this assay for detecting, staging and monitoring prostate cancer.

Biopsy, Needle↗
PubMed1998

Frequent occurrence of metastatic disease in patients with renal cell carcinoma and intrahepatic or supradiaphragmatic intracaval extension treated with surgery: an outcome analysis.

OBJECTIVES: Previous reports indicate that up to 10% of patients with localized renal cell carcinoma have direct intracaval neoplastic extension. Many patients with locally confined tumors and small intracaval tumor extensions can be surgically cured. Few studies have documented long-term survival after radical surgery for renal cell carcinoma involving higher vena caval tumor extension. We report the follow-up of 34 consecutive patients undergoing radical nephrectomy and intrahepatic or supradiaphragmatic intracaval thrombectomy for renal cell carcinoma. METHODS: From October 1982 through January 1993, 34 consecutive patients with a mean age of 60 years were identified as having clinical Stage T3 renal cell carcinoma (mean diameter 9.5+/-4.0 cm) with intrahepatic (41%) or supradiaphragmatic (59%) intracaval neoplastic extension. Patients underwent radical nephrectomy with intrahepatic caval thrombectomy (38%) or supradiaphragmatic caval thrombectomy using cardiac bypass with hypothermia and circulatory arrest (62%). Clinical outcome was assessed during a mean follow-up of 30 months (range 1 to 182). RESULTS: A total of 24 (71%) of 34 tumors demonstrated capsular penetration, and 22 (65%) of 34 had significant perinephric extension into Gerota's fascia by pathologic analysis. Metastatic disease was identified in 35% of patients either at the time of surgery or by pathologic analysis. Using Kaplan-Meier actuarial analysis, the likelihood of survival for all 34 consecutive patients after surgery was 68% (95% confidence interval [CI] 49% to 81%) at 1 year, 32% (95% CI 18% to 48%) at 2 years, 14% (95% CI 5% to 28%) at 5 years, and 9% (95% CI 2% to 24%) at 10 years. Neither capsular penetration, perinephric extension, the level of intracaval extension of tumor, nor the use of cardiopulmonary bypass significantly affected survival. CONCLUSIONS: In patients with renal cell carcinoma and intrahepatic or supradiaphragmatic intracaval extension of tumor, the presence of metastases is a frequent occurrence and, if present, greatly diminishes survival. Improvements in the preoperative detection of occult metastases are needed if surgery alone is to improve survival.

Adult↗
PubMed1998

Use of multivariate models to improve prediction of pathologic stage for men with clinically localized prostate cancer.

To benefit from definitive local therapy, men with clinically localized prostate cancer should have organ-confined disease. We discuss the use of multivariate analysis using serum PSA, biopsy Gleason score and clinical stage to improve the prediction of pathologic stage. Serum PSA, biopsy Gleason scores and clinical stage correlate with pathologic stage by univariate analysis are used in this study. However, each of these variables cannot accurately predict stage for the individual patient. Several investigators have proposed clinical algorithms based on multivariate analysis to enhance pretreatment staging. For men with clinically localized prostate cancer, multivariate algorithms are useful to determine the probability of a man having organ-confined disease, seminal vesicle invasion and lymph node involvement. This information will better enable clinicians and patients to make informed decisions about appropriate treatment options.

Journal Article↗
PubMed1998

Comparison of radical prostatectomy and iodine 125 interstitial radiotherapy for the treatment of clinically localized prostate cancer: a 7-year biochemical (PSA) progression analysis.

OBJECTIVES: To evaluate the relative efficacy of brachytherapy to radical prostatectomy, we compared biochemical progression rates from a published series of men who underwent iodine 125 (125I) interstitial radiotherapy for localized prostate cancer to a similar group of men who underwent anatomic radical prostatectomy using appropriate end points. METHODS: Seventy-six men who underwent anatomic radical prostatectomy between 1988 and 1990 were carefully matched for Gleason score and clinical stage to a recently reported contemporary series of patients treated at another institution with 125I brachytherapy without adjuvant treatment. The definition of biochemical progression was a serum PSA level greater than 0.2 ng/mL after anatomic radical prostatectomy and greater than 0.5 ng/mL for brachytherapy-treated patients. RESULTS: The 7-year actuarial PSA progression-free survival following anatomic radical prostatectomy was 97.8% (95% confidence interval [CI], 85.6% to 99.7%) for this group of men selected to match the brachytherapy group, compared to 79% (95% CI not published) for men treated with 125I interstitial radiotherapy. CONCLUSIONS: Using comparative end points for biochemical-free progression, failure rates may be higher following 125I interstitial radiotherapy compared to anatomic radical prostatectomy. These data provide a better comparison of biochemical progression than previously published studies and emphasize the need for caution in interpreting the relative efficacy of brachytherapy in controlling localized prostate cancer.

Adult↗
PubMed1998

Multivariate models as predictors of pathological stage using Gleason score, clinical stage, and serum prostate-specific antigen.

The patient presented is a 58-year-old man with newly diagnosed prostate cancer who likely has at least a 10- to 15-year life expectancy. In staging this man's extent of disease, several preoperative clinical variables are provided to assess whether the patient has local disease before offering definitive surgical therapy. It has been demonstrated that the combination of several of these variables in a multivariate analysis has greater predictive power than any of these variables do alone. Multivariate analysis using clinical stage, prostate-specific antigen (PSA), and Gleason score will provide both the physician and patient with 95% confidence intervals for determining the probability of having organ-confined disease, extracapsular penetration, seminal vesicle involvement, and lymphatic metastases. Several of the clinical variables given indicate that this patient has advanced disease, such as a PSA of 12 ng/mL, a stage T2b lesion, Gleason sum 7 disease in 2 of 3 cores from the right side associated with perineural invasion, and an additional Gleason sum 7 biopsy from the contralateral apex. For a man with these preoperative variables, there is a 13% chance of organ-confined disease, an 18% probability of seminal vesicle invasion, and a 17% chance of positive pelvic lymph nodes based on a nomogram constructed from multivariate analysis. Using this information, this man should be counseled that he has a high probability (87%) of extracapsular disease and a significant risk (15% to 20%) of having either seminal vesicle or lymph node involvement. Recognizing the risks and benefits of various forms of definitive therapy for prostate cancer, the patient has additional information to make an informed decision.

Humans↗
PubMed1996

High-density mapping of chromosomal arm 1q in renal collecting duct carcinoma: region of minimal deletion at 1q32.1-32.2.

Collecting duct carcinoma (CDC) of the kidney is a rare malignant neoplasm of distal nephron origin. Previous studies of CDC have shown loss of heterozygosity on chromosomal arm 1q in 57% of the cases studied. To better characterize 1q loss in CDC, we performed high-density mapping of the entire long arm of chromosome 1 in 13 CDC tumor samples. We observed complete deletion of chromosomal arm 1q in 5 samples and partial deletion in 4 additional tumors. Our study further showed that the region of minimal deletion is located at 1q32.1-32.2. Sixty-nine percent (9 of 13) of the tumors showed loss of heterozygosity in this area. These data suggest that a gene or group of genes that contribute to the development of distal nephron tumors may be located within the 1q32.1-32.2 region.

Chromosome Deletion↗