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M L Cher

Publications and source records attributed to M L Cher.

32 records · Page 2Linked to original sources
PubMed1997

A t-statistic for objective interpretation of comparative genomic hybridization (CGH) profiles.

An objective method for interpreting comparative genomic hybridization (CGH) is described and compared with current methods of interpretation. The method is based on a two-sample t-statistic in which composite test:reference and reference:reference CGH profiles are compared at each point along the genome to detect regions of significant differences. Composite profiles are created by combining CGH profiles measured from several metaphase chromosomes for each type of chromosome in the normal human karyotype. Composites for both test:reference and reference:reference CGH analyses are used to generate mean CGH profiles and information about the variance therein. The utility of the method is demonstrated through analysis of aneusomies and partial gain and loss of DNA sequence in a myeloid leukemia specimen. Banding analyses of this specimen indicated inv (3)(q21q26), del (5)(q2?q35), -7, +8 and add (17)(p11.2). The t-statistic analyses of CGH data indicated rev ish enh (8) and rev ish dim (5q31.1q33.1,7q11.23qter). The undetected gain on 17p was small and confined to a single band (17p11.2). Thus, the t-statistic is an objective and effective method for defining significant differences between test and reference CGH profiles.

Humans↗
PubMed1997

Accelerated tumor proliferation rates in locally recurrent prostate cancer after radical prostatectomy.

PURPOSE: We compared the growth rates of primary cancer and prostatic fossa recurrence after radical prostatectomy. MATERIALS AND METHODS: Tumor proliferative rates were studied in 26 patients with biopsy proved prostatic fossa recurrences after radical prostatectomy. Proliferation was calculated in the prostatectomy specimens and in recurrent cancer using Ki-67 antibody to detect dividing cells. RESULTS: Mean and median labeling indexes for radical prostatectomy specimens were 2.96 and 2.51, respectively. Labeling indexes in locally recurrent tumors were significantly higher (mean 6.47, median 5.59, p < 0.001). The increase in labeling index between parent and recurrent tumors was unrelated to pathological staging at prostatectomy or interval from radical prostatectomy. CONCLUSIONS: Tumors that recur locally after radical prostatectomy appear to have a higher proliferative rate compared to parent tumors.

Cell Division↗
PubMed1996

Genetic alterations in untreated metastases and androgen-independent prostate cancer detected by comparative genomic hybridization and allelotyping.

A newly developed method of comparative genomic hybridization (CGH) employing quantitative statistical comparisons was applied to DNA from two different types of advanced prostate cancer tissue. Multiple CGH analyses were obtained for each chromosome in each tumor, and the results of point-by-point comparison of the mean tumor:normal color ratio to a control normal:normal color ratio in each of 1247 evenly distributed data channels constituting the entire human genome were interpreted as loss, gain, or no change in copy number in the tumor genome. Group I tissue was obtained from prostate cancer metastases from 20 patients, 19 of whom had received no prior prostate cancer treatment. This DNA also was analyzed by Southern and microsatellite allelotyping at 53 different loci on 20 different chromosome arms. CGH results agreed with allelotyping results at 92% of the informative loci studied. These samples, which contained highly enriched tumor DNA, showed the highest rates of alteration yet reported in several chromosomal regions known to be altered frequently in prostate cancer: 8q gain (85%), 8p loss (80%), 13q loss (75%), 16q loss (55%), 17p loss (50%), and 10q loss (50%). Group II tissue was obtained predominately from primary or recurrent tumor from 11 patients who had been treated with long-term androgen-deprivation therapy and developed androgen-independent metastatic disease. Quantitative CGH analysis on DNA from these tissues showed chromosomal alterations that were very similar to those found in group I, suggesting that untreated metastatic tumors contain the bulk of chromosomal alterations necessary for recurrence to occur during androgen deprivation. In the entire data set, a number of previously undetected regions of frequent loss or gain were identified, including losses of chromosomes 2q (42%), 5q (39%), 6q (39%), and 15q (39%) and gains of chromosomes 11p (52%), 1q (52%), 3q (52%), and 2p (45%). Chi-squared analysis showed a significantly higher frequency of gain of the 4q25-q28 region in tumors from African-American patients, indicating a possible oncogene whose activation may play a role in the higher rate of progression seen in this ethnic group. Additional study of these frequently altered regions may provide insight into the mechanism of prostate cancer progression and lead to important tools for tumor-specific prognosis and therapy.

Adult↗
PubMed1996

Identification of genetic alterations associated with the process of human experimental colon cancer liver metastasis in the nude mouse.

Understanding the genetic elements controlling the process of tumor metastasis to distant organ sites such as the liver may be the key to improving survivorship from colon cancer. By using standard cytogenetic techniques in combination with comparative genomic hybridization, multiple genetic imbalances within three human colon cancer cell lines previously selected for differences in liver-metastatic behavior were identified. The entire genome of one poorly metastatic cell line (KM12C) was compared directly with that of two highly metastatic cell lines (KM12SM, KM12L4A) derived from it. A number of chromosomal gains (8q, 12q15, 20q11.2) and losses (5p13, 6p21.3, 18) were common to all three cell lines and are likely related to early tumor development rather than to the selection process used to generate cell lines of increased metastatic potential. Chromosomal imbalances detected only in the highly metastatic cell lines were also observed. KM12SM showed losses of portions of 2p22, 2q24.3--> 2q32.2, 4p15.3--> cen, 4q24 without the 13q and 15q22.3 gains noted for KM12C. Both gains (1p31.3--> 1p21, 2q22--> 2q33, 3cen--> 3q26.2, 5q14--> 5q23, 6cen--> 6q23) and losses (16p, 17p, 17q 19p, 19q 22q) were observed for KM12L4A but not for the other two cell lines. Identification of these alterations provides valuable insight into the process of experimental liver metastasis and is a first step towards mapping genes linked to the terminal phases of human colon cancer progression.

Animals↗
PubMed1996

Smooth-muscle myosin heavy-chain isoform expression in bladder-outlet obstruction.

Bladder-outlet obstruction leads to detrusor smooth-muscle hypertrophy/hyperplasia. Despite this overall increase in muscle mass, smooth-muscle contractility decreases and bladder emptying is impaired. The goal of this study was to determine whether smooth-muscle myosin heavy-chain (MHC) alterations occur in conjunction with partial obstruction of the rabbit bladder. Total MHC and MHC-isoform protein concentrations were determined by quantitative gel electrophoresis in rabbit bladders partially obstructed for 1-4 weeks. MHC gene expression was assessed by Northern and nuclease protection assays. Two MHC isoforms (SM1/SM2) were identified in the normal rabbit bladder. After 2 weeks of obstruction the ratio of SM1/SM2 changed from 0.4:0.6 to 0.5:0.5 (P < 0.01). As compared with sham-operated values, the level of MHC mRNA decreased significantly as of 1 day after obstruction. Quantitation of MHC-isoform mRNA levels revealed a nearly 3-fold increase in the SM1/SM2 ratio. In this animal model of bladder-outlet obstruction, early changes in MHC isoforms as well as an overall decrease of MHC mRNA expression were demonstrated, suggesting that obstruction induces significant alterations in myofilament gene expression.

Animals↗
PubMed1996

Cellular proliferative fraction of metastatic lymph nodes predicts survival in stage D1 (TxN+M0) prostate cancer.

PURPOSE: We assessed the ability of tumor cellular proliferative fraction to predict long-term survival among patients with lymphatic metastases from prostate cancer. MATERIALS AND METHODS: We studied 50 patients with stage D1 (TxN+M0) prostate cancer who underwent pelvic lymphadenectomy and 125iodine seed implantation between 1970 and 1978. We used the MIB-1 monoclonal antibody to Ki67 to stain sections of the lymphatic metastases in these patients. The Ki67 proliferative fraction was defined as the fraction of positively stained malignant nuclei. We also used flow cytometry to determine the deoxyribonucleic acid content of the lymphatic metastases. RESULTS: Median followup was 6.1 years. Patients whose metastases had a Ki67 proliferative fraction of less than 0.1 had significantly longer survival compared to those with a proliferative fraction of greater than 0.1 (8.7 years versus 4.4 years, respectively, p = 0.005, log rank test). The Ki67 proliferative fraction and ploidy were not independent variables. Patients whose metastases were diploid had a significantly longer survival than those with aneuploid metastases (8.8 years versus 4.4 years, respectively, p = 0.01, log rank test). Multivariate analysis showed that ploidy had a slightly stronger effect on survival than did the Ki67 proliferative fraction. CONCLUSIONS: Cellular proliferative fraction of lymphatic metastases is useful to predict survival in patients with stage D1 prostatic carcinoma. Proliferative fraction may be useful as a marker of progression among patients with other stages of disease.

Biomarkers, Tumor↗
PubMed1995

Cellular proliferation in prostatic adenocarcinoma as assessed by bromodeoxyuridine uptake and Ki-67 and PCNA expression.

Prostatic carcinomas vary in their biological potential, even when stratified by grade and stage. Measurement of cellular proliferation by various methods has been shown to correlate with outcome for several human cancers, including prostatic carcinoma. Uptake of bromodeoxyuridine (BrdUrd), a thymidine analogue, has been accepted as a measure of cellular proliferative rate. However, the technique is somewhat complex, requiring incubation with fresh tissue. We compared cellular proliferation as measured by BrdUrd uptake with two more simple immunohistochemical methods in 44 prostatic adenocarcinoma specimens and correlated the results with standard clinical parameters. The tissue was obtained via needle biopsy, channel transurethral resection, and radical prostatectomy. Specimens were incubated in vitro with BrdUrd and then fixed and paraffin embedded. Sections were immunohistochemically stained with antibodies to BrdUrd, proliferating cell nuclear antigen (PCNA), and Ki-67. At least 1,000 cells were scored, and a labeling index (LI) was calculated (number of positive cells/total number of cells). The mean LI determined by all three indices was low (BrdUrd = 3.0, PCNA = 7.0, Ki-67 = 3.4), consistent with the knowledge that prostatic tumors grow slowly. In 36 patients who had not been treated at the time of analysis, the LI as determined by all three methods correlated well with clinical stage and pathological grade. Furthermore, the LIs discriminated between those with tumor confined to the prostate and those with extension to the seminal vesicles, lymph nodes, or bone (P = 0.003, 0.004, 0.008 for BrdUrd, PCNA, and Ki-67, respectively). The LIs for PCNA and Ki-67 correlated well with that for BrdUrd (r = 0.84; r = 0.85), while the LIs for Ki-67 and PCNA correlated slightly less well with each other (r = 0.78). PCNA and Ki-67 expression appear to reflect essentially the same biological process as BrdUrd uptake. Either can substitute for BrdUrd as a measure of cellular proliferation, and Ki-67 seems to offer the fewest technical problems.

Adenocarcinoma↗
PubMed1995

Mapping of regions of physical deletion on chromosome 16q in prostate cancer cells by fluorescence in situ hybridization (FISH).

Recent evidence suggests that a tumor suppressor gene important in the progression of prostatic carcinoma may reside on chromosome 16q. The exact location and identity of this gene are unknown. We used fluorescence in situ hybridization in a novel manner to define more clearly the location of this gene. Region-specific chromosome 16 cosmid contig probes were hybridized directly to interphase prostatic carcinoma nuclei in order to measure physical deletion of chromosomal loci. Fifteen of 30 tumors (50%) showed evidence of physical deletion of 16q24. Other probes were used to test for regions of chromosome 16 deletions in the same specimens, and a map showing a region of common deletion was created. This map showed the proximal terminus of the region of common deletion to be located distal to 16q23.1. These data correlate well with loss of heterozygosity data in the literature and provide further evidence for the presence of a prostatic carcinoma tumor suppressor gene on chromosome 16q.

Chromosome Deletion↗
PubMed1995

High failure rate associated with long-term follow-up of neoadjuvant androgen deprivation followed by radical prostatectomy for stage C prostatic cancer.

OBJECTIVE: To evaluate whether neoadjuvant androgen deprivation before radical prostatectomy decreases tumour stage in patients with stage C prostatic cancer and to estimate the efficacy of cancer control achieved with this form of treatment. PATIENTS AND METHODS: Thirty men (mean age 65 years, range 52-74) with clinical stage C adenocarcinoma of the prostate were included in a phase II trial of neoadjuvant androgen deprivation (luteinizing hormone-releasing hormone agonist and an antiandrogen) before radical prostatectomy. The timing and extent of the changes in serum prostate specific antigen (PSA) levels and both prostate and cancer volume were recorded. Twenty-six men underwent radical prostatectomy with pelvic lymphadenectomy, two had pelvic lymphadenectomy alone, one had pelvic lymphadenectomy with radiotherapy and one refused additional treatment despite significant reductions in tumour volume and PSA while undergoing androgen deprivation. RESULTS: The toxicity of the treatment was low. Significant reductions in prostatic volume (mean 35%), tumour volume (mean 50%) and PSA concentrations (mean 96%) occurred in all patients, with the maximum reductions recorded during the first 2 months of androgen deprivation. However, despite significant physiological changes in prostate and tumour volume, tumour stage was reduced in only four patients. Of the patients who were surgically staged 41% were ultimately identified as having more advanced disease, including lymph node metastases in 21%. Overall, with a mean follow-up of 32.7 months, 72% of patients had evidence of disease recurrence, including detectable PSA. Of 26 patients who underwent radical prostatectomy, local recurrence occurred in five (19%), distant recurrence in one (4%) and both local and distant recurrence in one (4%). CONCLUSIONS: This study suggests that tumour stage reduction is uncommon in patients with stage C prostatic cancer treated with neoadjuvant androgen deprivation followed by radical prostatectomy. Furthermore, local and distant recurrences, as well as detectable levels of PSA, are common after such treatment.

Adenocarcinoma↗
PubMed1995

Screening for prostate cancer.

Prostate cancer is a serious health care problem in the United States. Whether or not to screen for it has become a timely issue. Although a large number of men have clinically important, asymptomatic, undetected prostate cancer, an even larger number have clinically unimportant cancer. To justify screening programs, not only must we avoid detecting biologically unimportant cancers, we must also detect and effectively treat that subset of tumors that, if undiagnosed, would progress, produce symptoms, and reduce life expectancy. Serum prostate-specific antigen (PSA) assay, or its variations such as PSA density, PSA velocity, and age-specific reference ranges, and the digital rectal examination are the best tests for detecting clinically important, asymptomatic, curable tumors. Recent data suggest that using serum PSA levels does not result in an overdetection of unimportant tumors. Highly effective, curative treatment of localized prostate cancer is available. These factors promote optimism that screening for prostate cancer will ultimately prove beneficial. Nonetheless, men should be informed regarding the benefits and possible risks before being screened for prostate cancer.

Humans↗
PubMed1994

Comparative genomic hybridization, allelic imbalance, and fluorescence in situ hybridization on chromosome 8 in prostate cancer.

Due to problems with primary tumor cell culture, conventional cytogenetics has yielded little insightful information on chromosomal alterations in prostate cancer. The primary aim of this study was to define the ability of comparative genomic hybridization (CGH) to detect and map genetic deletions in prostate tumors. A secondary aim was to apply multiple assays to individual tumors as a means of deciphering the mechanisms of genetic alterations in prostate cancer. CGH results were compared with allelic imbalance measurements at 29 distinct loci on chromosome 8 in 18 specimens (17 malignant and 1 benign). CGH detected no changes in cases where all informative PCR/RFLP loci were retained and detected all p arm deletions consisting of at least two loci. We estimate that in this study, the smallest deletions detected by CGH were approximately 20-30 cM. Physical mapping of subchromosomal arm deletions by CGH correlated well with allelic imbalance mapping by PCR/RFLP: The data agreed at 88% of loci on 8p and 92% of loci on 8q. Fluorescence in situ hybridization (FISH) with multiple centromere probes and DNA content flow cytometry (FCM) also was performed on selected specimens. FISH revealed two cases of chromosome 8 aneusomy. In these two cases and three others, CGH showed simultaneous p arm deletion and q arm gain, suggesting isochromosome 8q formation. Together, these data suggested that, simple chromosomal aberrations were responsible for allelic losses on 8p and allelic gains on 8q in a significant number of prostate tumors. We also used CGH to examine relative DNA sequence copy number throughout the genome. Changes frequently associated with 8p loss include gains of 8q and losses of 13q, 16p, 16q, 17p, 17q, 20q, and Y. Cases with 8p loss exhibited five times the number of alterations as did cases without 8p loss.

Alleles↗
PubMed1993

Continence in the myelodysplastic patient following enterocystoplasty.

To evaluate the ability of augmentation cystoplasty alone to provide a low pressure bladder and an adequate degree of continence in the myelodysplastic patient, the clinical records and urodynamic data of the last 18 consecutive such patients undergoing augmentation cytoplasty at our institution were reviewed. Two patients underwent colocystoplasty and 16 underwent ileocystoplasty. No patient underwent any procedure on the bladder neck or urethra. The 2 colocystoplasty patients exhibited episodic dampness attributed to contractions of the augmentation but all of the ileocystoplasty patients were dry during the day except 1 who had a urethral resistance of only 19 to 22 cm. water. On the basis of this review, ileocystoplasty alone appears to be sufficient for satisfactory continence in patients with a neurogenic bladder undergoing vesical augmentation if bladder outlet resistance exceeds 25 to 30 cm. water.

Adolescent↗