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Biomedical subjects

B W Hancock

Publications and source records attributed to B W Hancock.

At least 73 records · Page 4Linked to original sources
PubMed1996

Investigation of the RB-1 tumour suppressor gene in a United Kingdom series of non-Hodgkin's lymphomas.

We have investigated the RB-1 tumour suppressor genes in a series of 20 non-Hodgkin's lymphomas (NHL). Polymerase chain reaction (PCR) amplification of polymorphic alleles indicated that there was evidence of allelic imbalance around 13q14, the site of the RB-1 gene, in at least 5 NHL. Immunohistochemical analysis of the RB-1 protein demonstrated wide variations in the percentage of cells exhibiting positive staining, but these usually correlated with differences in the proliferation index as indicated by staining of Ki67. Only 3/35 NHL exhibited significantly fewer cells expressing RB-1 protein than expressed Ki167. A comprehensive analysis of the mutation status of RB-1 in 20 NHL was carried out using PCR based strategies involving single strand conformational polymorphism (SSCP) gels. Most of the protein coding region was studied by analysing cDNA derived from its mRNA and the remaining 5'-end of the coding region investigated by analysing exon I of the gene. We also examined the promoter region of the gene. In none of the 20 NHL investigated were we able to identify a mutation: the only abnormal migrating fragment observed proved to be a polymorphism in exon I of the gene in 5 NHL. In one other case we detected instability at an intron repeat sequence, which had occurred during progression of the disease, but again no mutation of the protein coding region was found. The low levels of RB-1 protein expression that we had observed in a few of our NHL therefore did not appear to be due to mutation of the gene. These data suggest that mutation of RB-1 is not a common event in the evolution of NHL, but that there may be another, as yet unidentified, tumour suppressor gene near the RB-1 locus which is associated with NHL.

Alleles↗
PubMed1995

A multicenter phase II clinical trial using dacarbazine and continuous infusion interleukin-2 for metastatic melanoma. Clinical data and immunomonitoring.

BACKGROUND: Treatment of patients with metastatic melanoma with either dacarbazine or recombinant interleukin-2 (rIL-2) resulted in a response rate of approximately 15%. This study investigates the possible synergism of this chemoimmunotherapy combination. METHODS: Fifty-seven patients with metastatic malignant melanoma received 135 treatment cycles. Treatment consisted of dacarbazine (Days 1-5) at 250 mg/m2 by a 30-minute slow infusion, and interleukin-2 by constant intravenous infusion (Days 21-25 and 28-32) at 18 x 10(6) IU/m2/24 hours. After this treatment cycle, a 1-week rest was scheduled, and in the absence of undue toxicity or tumor progression, patients received a second cycle as described. Maximum treatment consisted of two induction and four maintenance cycles. In a subgroup of patients, immunoparameters were analyzed to identify prognostic factors. Standard supportive care was given. RESULTS: Common toxicities included fever, hypotension, nausea/vomiting, anemia, leukopenia, thrombocytopenia, an increase in serum lactic dehydrogenase levels and diarrhea. The objective response rate was 15.8% (one complete response and eight partial responses). In 14 patients, the disease stabilized. For patients who had an objective response, median response duration was 13.9 months (6.3-39.0+), and median survival was 19.0 months (6.3-39.0+); overall survival was 9.3 months (0.8-39.0+). Immunomonitoring did not reveal any relevant prognostic factors for overall response. CONCLUSIONS: Sequential treatment with dacarbazine and rIL-2 is feasible and produces long-lasting responses in a minority of patients.

Adult↗
PubMed1995

Simultaneous choriocarcinoma in mother and newborn infant.

A male infant, born following an uncomplicated pregnancy, was severely anaemic at birth following significant foeto-maternal haemorrhage. At three weeks of age a tumour was found in the liver with evidence of metastatic disease in the lungs. The infant died before treatment could be started. Postmortem revealed choriocarcinoma which led to subsequent diagnosis in the mother who also had pulmonary metastases. The mother has been successfully treated. The case is described in detail and followed by a discussion and a literature review of reported cases of simultaneous choriocarcinoma in infant and mother.

Choriocarcinoma↗
PubMed1995

Analysis of 14q+ derivative chromosomes in non-Hodgkin's lymphomas by fluorescence in-situ hybridization.

The most common chromosomal abnormality observed in non-Hodgkin's lymphomas (NHL) involves the structural alteration of the q arm of chromosome 14. It is not always possible, however, to fully analyse such derivative chromosomes by Giemsa-banding. Therefore, we have applied the fluorescence in-situ hybridization (FISH) technique of chromosome painting to elucidate the origins of the der(14) chromosomes in 8 cases of NHL. In 2 NHL the der(14) appeared to be the product of the t(14;18)(q32;q21) translocation, but were not accompanied by the reciprocal der(18) chromosome. In 3 cases the breakpoint was at 14q32 but the translocated material appeared not to be from chromosome 18 and in 2 cases the breakpoint was centromeric to 14q32. One case with a t(14;18)(q32;q21) was also analysed as a control. Dual painting was carried out with paints for chromosome 14 and either chromosome 3, 8, 10, 11, 18 or 19. In the control and 2 other cases the translocated material was demonstrated to be from chromosome 18, in two cases it was from chromosome 3 and in 1 case there was an unusual insertion of chromosome 11 material. We were unable to identify the origins of the translocated material in 1 NHL and in the final case the apparent der(14) was demonstrated not to contain chromosome 14 material. These data demonstrated the utility of the FISH technique for analysing malignant cell karyotypes, and in particular indicated the potential of this approach for identifying cases containing putative NHL associated oncogenes that may have been translocated adjacent to the immunoglobulin locus at 14q32.

Chromosome Aberrations↗
PubMed1995

MDR-1 expression in non-Hodgkin's lymphomas is unrelated to treatment intensity or response to therapy.

Over-expression of the MDR-1 gene, which codes for P-glycoprotein, is thought to be an important mechanism in the drug resistance exhibited by many tumours. A number of chemotherapeutic agents which induce MDR-1 expression are also components of combination chemotherapies that are used in the treatment of high grade non-Hodgkin's lymphomas (NHL). We have therefore examined expression of MDR-1 in a series of NHL by Northern blot analysis as well as investigated the localization of P-glycoprotein by immunohistochemistry. The series included 11 hyperplastic reactive nodes and tonsils, 17 low grade NHL and 15 high grade NHL. The levels of MDR-1 mRNA were quantified by scanning densitometry and comparison with levels of glucose-6-phosphate dehydrogenase (G6PD). The MDR-1 mRNA was observed in both non-malignant and NHL tissues. Immunohistochemical staining revealed that expression of MDR-1 mRNA in reactive nodes was related to the presence of P-glycoprotein in lymphocytes, however, P-glycoprotein was apparent in both the reactive lymphocytes and tumour cells in the NHL samples. Elevated mRNA levels (2-3 fold increase) were observed in some low grade and high grade NHL relative to those observed in reactive lymphoid tissue. There appeared to be little correlation, however, between expression of the MDR-1 gene and either treatment intensity or response to therapy. The drug resistance that is often encountered in NHL patients is therefore likely to involve mechanisms other than over-expression of P-glycoprotein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Activation of MYCN in a case of non-Hodgkin's lymphoma.

We have examined a series of non-Hodgkin's lymphomas (NHL) for evidence of expression of the MYC gene family. Northern blot analysis of RNA samples derived from 11 non-malignant reactive lymphoid tissues and 33 NHL was used to investigate expression of MYC, MYCL and MYCN. As expected MYC expression was detected in all samples. The levels of MYC expression were quantified by densitometry and appeared to be 3-8 fold higher in high grade NHL than in the low grade NHL or non-malignant lymphoid tissue. No expression of MYCL was detected in any sample. Expression of MYCN was however observed in one sample, which had been diagnosed as a T-cell high grade NHL. A detailed cytogenetic analysis of this sample proved difficult to obtain but, by using fluorescence in-situ hybridization (FISH), we were able to demonstrate that on one of the chromosomes 2 the MYCN gene was localised to a translocation breakpoint region. It therefore appears that in NHL it is possible for MYCN, like MYC in Burkitt lymphoma, to be activated as a result of a chromosome translocation event.

Chromosome Aberrations↗
PubMed1994

Elevated levels of MDM-2 and p53 expression are associated with high grade non-Hodgkin's lymphomas.

The role of p53 in the evolution of non-Hodgkin's lymphomas (NHL) is unclear. Mutations of the p53 gene appear to be relatively uncommon but stabilized p53 protein, as detected by immunohistochemistry, has indicated a more frequent involvement of p53. As dysfunction of p53 protein has also been suggested to occur after overexpression of the mdm-2 protein, we have therefore investigated a series of non-malignant hyperplastic reactive lymphoid tissues and NHL to examine whether the levels of expression of MDM-2 correlated to positivity of p53 protein staining. Northern blot analysis of MDM-2 expression was compared to glucose-6-phosphate dehydrogenase (G6PD) expression by densitometry to quantify the relative levels of MDM-2 expression. Consistent low levels of MDM-2 expression were observed in non-malignant lymphoid tissue and in low grade NHL, however, 13/15 high grade NHL exhibited a 2-15-fold increase in MDM-2 expression. Interestingly similar elevations in p53 mRNA expression were also observed in 6/15 high grade NHL. Positive staining of the p53 protein did not, however, correlate with elevated mRNA levels of either MDM-2 or p53. The significance of these observations is discussed.

Blotting, Northern↗
PubMed1994

Comparison of protein synthesis profiles in chronic lymphocytic leukaemia cells and B-lymphocytes from peripheral blood, cord blood and tonsil.

2D-gel electrophoresis was used to investigate protein synthesis in leukaemic cells from a series of 15 chronic lymphocytic leukaemia (CLL) patients, and in non-malignant B-cell populations from different sources. The protein synthesis profiles of CD5+ B-cells from umbilical cord blood and from tonsil were determined, and the levels of expression of their proteins were observed to be similar to the CLL cells. The CD5- cells from cord blood resembled peripheral blood B-lymphocytes, and the protein synthesis profile of CD5- cells from tonsils was very complex. One protein was also identified which consistently appeared to be synthesised at a low level in CD5+ B-cells from tonsil but which was always more prominent in CLL cells and other non-malignant B-lymphocytes. On the basis of these data it is possible that the closest non-malignant counterpart to CLL is the CD5+ B-lymphocyte from cord blood.

Antigens, CD↗
PubMed1994

Identification of a subclass of double minute chromosomes containing centromere-associated DNA.

In a study of abnormal chromosomes in non-Hodgkin's lymphoma (NHL) cells we have identified one case which contained extrachromosomal chromatin bodies that, on the basis of their morphology and negative C-banding, appeared to be double minute chromosomes (dmin). However, fluorescence in-situ hybridization (FISH) analysis using an X-specific centromeric alphoid repeat probe and a pan-centromere probe, clearly demonstrated the presence of centromere-associated DNA in these dmin. FISH analysis with the pan-centromere probe of the dmin in neuroblastoma and sarcoma cells failed to reveal the presence of centromere-associated DNA, but analysis of two cases of acute myeloid leukemia cells revealed centromere-associated DNA in 25% of their dmin. These data indicate the existence of dmin that contain centromere-associated DNA and suggest that such dmin might represent a new class of extrachromosomal chromatin bodies.

Biopsy↗
PubMed1994

P53 mutation in a series of epithelial ovarian cancers from the U.K., and its prognostic significance.

In an initial study of 20 fresh ovarian tumour samples, we compared the immunohistochemical positivity of staining of the p53 protein with the presence of missense mutations of the p53 gene. This revealed a prevalence of 50% with a perfect correlation between mutation and immunohistochemical staining. Detection of the p53 protein by immunohistochemistry was, therefore, used as a reliable indicator for the presence of P53 mutation, and was applied to a study of an archival series of 93 ovarian tumours. Positive immunostaining of the p53 protein was observed in 47% of this series. Cox regression was used to assess whether various clinical variables and P53 mutation were related to survival. As a result, it was found that positive staining of the p53 protein was independent of age, tumour differentiation, tumour type, though possibly not stage. There was some evidence that p53 positivity was associated with reduced survival after adjusting for other variables, but the result was not statistically significant.

Biomarkers, Tumor↗
PubMed1994

Investigation of the activation state of the X chromosome in non-Hodgkin's lymphomas.

Cytogenetic analysis of non-Hodgkin's lymphomas (NHLs) has previously revealed a high incidence of numerical abnormalities involving the X chromosome. We have now used a combination of fluorescence in situ hybridization (FISH) and Southern blot analysis of methylation to examine the activation state of additional X chromosomes in NHL. Although FISH analysis of X chromosome centromeres in interphase nuclei was complicated by a number of factors, such as cell-cycle position, there was evidence that more than one X chromosome was present in the active state in 4/9 NHL. Methylation studies were carried out using the M27 beta probe, which also suggested that more than one activated X chromosome was present in at least 2/7 NHL cases. The two approaches therefore provided evidence that in some cases of NHL, unlike sex-chromosome-syndrome individuals, additional X chromosomes may be present in the active state. These data support the suggestion that NHL-associated oncogenes might be located on the X chromosome.

Blotting, Southern↗
PubMed1994

Chromosome analysis of non-Hodgkin's lymphomas by fluorescence in situ hybridization.

We have recently carried out a cytogenetic survey of a series of non-Hodgkin's lymphomas (NHLs) and identified chromosomal abnormalities in most of the samples studied. A third of these cases, however, had to be recorded as containing derivative or marker chromosomes, whose origins were either partially or completely unknown. In an attempt to further analyse such cases, we have adopted the fluorescence in situ hybridization (FISH) technique. The FISH technique has allowed us to map the myb gene to 6q23, and then to study its position on 6q- derivative chromosomes in the NHL cells. The related FISH technique of chromosome painting has enabled us to identify a marker chromosome in one of our cases as an abnormal X chromosome, and in other cases has allowed 14q+ derivative chromosomes to be further analysed. We have also applied the FISH technique to the analysis of interphase nuclei, and have been able to determine numerical chromosome changes in NHL interphase cells. The application of the FISH technique to the study of NHL cell chromosomes is likely to enable the identification of most chromosomal abnormalities present, and so may reveal the critical events leading to malignant transformation of lymphoid cells.

Biopsy↗
PubMed1994

Analysis of the p53 gene, its expression and protein stabilization in non-Hodgkin's lymphomas.

We have investigated the p53 gene, expression of its mRNA, and stabilization of its protein in a series of non-Hodgkin's lymphomas (NHLs). Immunohistochemistry revealed positive staining of the p53 protein in node biopsies from 6/36 NHL patients, all of whom had high-grade disease. The remaining NHL samples, together with 3 reactive nodes, showed either negative staining or the staining of only occasional cells. In one case that exhibited intense nuclear staining in 90% of the cells, a mutation in the p53 gene was also observed. There was no evidence of rearrangements of the p53 gene in any of the NHL samples. Although p53 mRNA could not be detected in nonmalignant tissue, it was apparently overexpressed in 16/38 NHL, but this did not correlate with positive staining of the p53 protein. These data suggest that p53 dysfunction might play an important role in the evolution of some cases of NHL, and that mechanisms other than mutation of the p53 gene may be involved in stabilizing the p53 protein in these neoplasms.

Gene Expression↗
PubMed1994

Hybrid LOPP/EVA is not better than LOPP alternating with EVAP: a prematurely terminated British National Lymphoma Investigation randomized trial.

In a British National Lymphoma Investigation (BNLI) trial, patients with advanced Hodgkin's disease (stages IB, IIB, III, and IV) were randomized between initial treatment with a LOPP alternating with EVAP regimen and a LOPP/EVA hybrid regimen. The two regimens contained identical drug dosages and varied only in their scheduling. The complete remission (CR) rate in the hybrid regimen was significantly less than that in the alternating regimen, and the trial was terminated after approximately 18 months since there appeared to be no chance of the hybrid regimen ever proving superior to the alternating regimen. A total of 160 patients were entered into the trial before recruitment was terminated, 86 being randomized to the alternating regimen and 83 to the hybrid regimen. The CR rates for the alternating and hybrid arms were 65% and 40%, respectively (p < 0.002). The CR relapse-free survivals at 2 years in these two arms were 85% and 79%, respectively (p = 0.7); the overall disease-free survivals at 2 years were 57% and 32%; and the overall survivals at 2 years were 88% and 78% (p = 0.5). This trial emphasizes the impact of drug scheduling, which should be taken into account in the design of future hybrid regimens.

Adolescent↗
PubMed1994

Changes in the phenotypic characteristics of eosinophils from patients receiving recombinant human interleukin-2 (rhIL-2) therapy.

We have studied the properties of eosinophils from 26 patients with malignant melanoma and 16 patients with renal cell carcinoma (RCC) who were entered into a phase II clinical trial using various schedules of low-dose rhIL-2 immunotherapy. Eosinophilia was observed in 65% of melanoma patients and 100% of renal patients when receiving rhIL-2 therapy. The eosinophil count increased up to 20-fold approximately 5 d after the appearance of lymphocyte activation markers. This would be consistent with eosinophil kinetics and the release of soluble mediators, for example IL-5, from lymphocytes. Eosinophils from eosinophilic patients became hypodense compared to their pre-treatment levels as demonstrated by sedimentation through a discontinuous metrizamide density gradient; they also showed an increased expression of CD4, CD25 and CD11b cell surface activation markers. Eosinophil count could not be correlated to either patient survival or response to therapy in melanoma patients; however, patients with renal cell carcinoma demonstrated a significant correlation (P < or = 0.05) between eosinophil count and survival but not with clinical response. Therefore the maximum eosinophil count achieved during rhIL-2 therapy is of prognostic significance in patients with renal cell carcinoma.

Antigens, Surface↗
PubMed1994

2D-gel analysis of protein synthesis profiles of different stages of chronic lymphocytic leukaemia.

Protein synthesis profiles of leukaemic cells from 15 chronic lymphocytic leukaemia (CLL) patients were analysed by 2D-electrophoresis of 35S-methionine labelled proteins. This series of CLL included patients with stage A (7), B (4) and C (4) disease. Although the protein synthesis profiles were similar in all cases, some consistent differences were noted between the different stages. The levels of synthesis of three proteins (approximately 35 kD size) were of particular interest. Two of these were always expressed in stage C CLL but either infrequently or not at all in stage A or B CLL. By contrast a third protein was expressed at a much reduced level in stage C compared to stages A or B. This type of analysis could prove invaluable for identifying proteins whose expression was intimately associated with the evolution of CLL.

Electrophoresis, Gel, Two-Dimensional↗