Molecular basis of chemosensitivity of platinum pre-treated ovarian cancer to chemotherapy.

BACKGROUND: Ovarian cancer shows considerable heterogeneity in its sensitivity to chemotherapy both clinically and in vitro. This study tested the hypothesis that the molecular basis of this difference lies within the known resistance mechanisms inherent to these patients' tumours. METHODS: The chemosensitivity of a series of 31 ovarian tumours, all previously treated with platinum-based chemotherapy, was assessed using the ATP-based tumour chemosensitivity assay (ATP-TCA) and correlated with resistance gene expression measured by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) in a TaqMan Array following extraction of mRNA from formalin-fixed paraffin-embedded tissue. The results were standardised against a housekeeping gene (PBGD), and assessed by multiple linear regression. RESULTS: Predictive multiple linear regression models were derived for four single agents (cisplatin, gemcitabine, topotecan, and treosulfan), and for the combinations of cisplatin+gemcitabine and treosulfan+gemcitabine. Particularly strong correlations were obtained for cisplatin, gemcitabine, topotecan, and treosulfan+gemcitabine. No individual gene expression showed direct correlation with activity in the ATP-TCA. Genes involved in DNA repair and apoptosis were strongly represented, with some drug pumps also involved. CONCLUSION: The chemosensitivity of ovarian cancer to drugs is related to the expression of genes involved in sensitivity and resistance mechanisms.

Observational and cost analysis of the implementation of breast cancer sentinel node intraoperative molecular diagnosis.

BACKGROUND: Accurate intraoperative sentinel lymph node (SLN) assessment enables axillary clearance to be completed immediately in node-positive breast cancer patients. This article reports a study of the introduction of intraoperative molecular SLN analysis in routine clinical practice in the Portsmouth Breast Care Centre. DESIGN: There was prospective analysis of 254 consecutive patients who underwent SLN biopsy in a single centre. Nodes were sectioned at 2 mm intervals and alternate slices were analysed using a CE-marked assay for mammaglobin (MG) and cytokeratin 19 (CK19). Remaining slices of node were sent for histological analysis, which included CK19 immunohistochemistry. While the assay was being carried out, the surgeon performed the breast tumour resection. The cost per patient was estimated retrospectively and the cost effects on the hospital and primary care trust for a typical service were also estimated. RESULTS: A total of 491 SLNs from 254 patients were evaluated. The intraoperative assay showed positivity of SLNs for metastatic cells in 78 patients. There was 100% detection of macrometastases within sentinel nodes analysed by GeneSearch. Overall concordance between histological status, including micrometastases and GeneSearch analysis, was 95% (sensitivity 96%, specificity 95%). The cost per procedure was increased for wide local excision with SLN biopsy and intraoperative assessment compared with other models, but fewer procedures were carried out. CONCLUSION: Intraoperative assessment of SLNs in breast cancer using a molecular assay is a safe, acceptable and accurate technique that allows a reduction in the frequency of delayed axillary clearance surgery. Take-up of this method may be hampered by perverse incentives operating within healthcare funding.

Mechanisms of local immunosuppression in cutaneous melanoma.

Cutaneous melanoma is highly immunogenic, yet primary melanomas and metastases develop successfully in otherwise immunocompetent patients. To investigate the local immunosuppressive microenvironment, we examined the presence of suppressor T lymphocytes and tolerising dendritic cells (DCs), the expression of immunosuppressive cytokines (IL-10, TGFbeta1 and TGFbeta2) and the enzyme indoleamine 2,3-dioxygenase (IDO) using qRT-PCR and immunohistochemistry in primary skin melanomas, negative and positive sentinel lymph nodes (SLN), and lymph nodes with advanced metastases. Our results indicate that tolerogenic DCs and suppressor T lymphocytes are present in melanoma at all stages of disease progression. They express transforming growth factor beta receptor 1 (TGFbetaR1), and are therefore susceptible to TGFbeta1 and TGFbeta2 specifically expressed by primary melanoma. We found that expression of IDO and interleukin 10 (IL-10) increased with melanoma progression, with the highest concentration in positive SLN. We suggest that negative SLN contain immunosuppressive cells and cytokines, due to preconditioning by tolerogenic DCs migrating from the primary melanoma site to the SLN. In primary melanoma, TGFbeta2 is likely to render peripheral DCs tolerogenic, while in lymph nodes IDO and TGFbeta1 may have a major effect. This mechanism of tumour-associated immunosuppression may inhibit the immune response to the tumour and may explain the discrepancy between the induction of systemic immunity by anti-melanoma vaccines and their poor performance in the clinic.

Peptide based enzyme immunoassays for detecting hepatitis C antibodies in sera of people at high risk.

AIM: To evaluate the performance of three newly introduced enzyme immunoassays (EIAs) for hepatitis C virus (HCV) antibodies, based on synthetic oligopeptides as antigens. METHODS: Referred serum samples (n = 173) from people representing groups at high risk of HCV infection were studied. An EIA based on second generation recombinant polypeptide antigens was used for comparison. EIA reactivities were validated by testing repeatedly reactive samples in two recombinant antigen based immunoblot assays. RESULTS: In samples from patients with liver dysfunction and those with bleeding disorders sensitivity of the three peptide based EIAs, manufactured by Innogenetics NV, Biokit SA, and United Biomedical Inc., were all 93%; specificity and efficiency were all greater than 95%. In samples from blood donors (previously tested as positive by the Ortho and Abbott Second Generation EIA) specificity, sensitivity, and efficiency were 95% or greater in all three peptide assays. Sensitivity, specificity, and efficiency of the recombinant antigen based Ortho Second Generation EIA were 100%, 89%, and 93%, respectively, in sera of patients with liver disease and those with bleeding disorders; and 100%, 43%, and 83%, respectively, in prescreened samples from blood donors. CONCLUSION: The peptide EIAs are more specific but less sensitive than the Ortho EIA. Peptide based EIAs should be useful in validating the specificity of Ortho EIA reactivities.

Confirmation of second generation anti-hepatitis C virus enzyme immunoassays by antigenic cross-validation.

AIM: To determine if a scheme for validating enzyme immunoassay (EIA) results could be devised that did not require costly and methodically elaborate supplemental assays. METHODS: Samples (n = 525) from patients with haemophilia A, leukaemia, and chronic liver disease and at increased risk of hepatitis C virus infection were tested by EIA-1 (Ortho Diagnostics), an assay which uses recombinant HCV fusion proteins as antigens, and by EIA-2 (United Biomedical), an assay based on synthetic HCV oligopeptide antigens. RESULTS: Samples (n = 193) were repeatedly reactive in both EIAs. Of these, 190 (98%) yielded reactivities in both of two supplemental assays used, one an immunoblot assay (RIBA) using recombinant HCV polypeptides similar to EIA-1 antigens, and the other a neutralisation EIA (EIA-2N) based on antigenic competition with HCV peptides similar to EIA-2 antigens. The three samples not reactive in supplemental tests exhibited low EIA optical density (OD) values (signal/cutoff ratios of less than 3). Hence, all specimens reactive and yielding high OD values in both EIAs were also reactive in supplemental assays. Twenty four samples were reactive in EIA-1 only and nine (38%) of these were reactive in RIBA. Fourteen of the 15 (93%) specimens reactive in EIA-1 but not RIBA were derived from patients with chronic liver dysfunction. Two samples were reactive in EIA-2 only, of which one was reactive in EIA-2N and none in RIBA. CONCLUSIONS: Compared with EIA-2, EIA-1 yielded more validated reactive samples and resulted in more non-validated reactivities. It is therefore suggested that for clinical diagnosis: (i) EIA-1 be used for anti-HCV testing and EIA-2 for validation of EIA-1 reactivities; (ii) samples concordantly reactive in EIA-1 and EIA-2 and displaying high OD readings be considered HCV antibody positive without supplemental testing; (iii) supplemental testing by RIBA be limited to samples reactive in EIA-1 but equivocal or unreactive in EIA-2 and those concordantly reactive but exhibiting low absorbance readings.

Low prevalence of antibody to hepatitis C virus in north east England.

The prevalence of antibodies to hepatitis C virus (anti-HCV) was studied in North East England in blood donors, local multiply transfused patients, local high risk individuals, and chronic liver disease patients. Anti-HCV was detected by enzyme-linked immunosorbent assay (ELISA) in 2/1120 (0.18%) blood donors; 1/84 chronic renal failure patients on haemodialysis who had received 1,992 units of blood (seroconversion rate of 0.05% per unit transfused), 1/207 cardiac patients 6 months post cardiac surgery transfused with 1,403 units of blood (1 anti-HCV pre-operatively, seroconversion rate 0.07%), 40/50 haemophilia A patients treated with commercial factor VIII, and 38/100 intravenous drug users. In addition anti-HCV was detected by ELISA in 5/35 cryptogenic chronic liver disease patients, 5/5 confirmed by recombinant immunoblot assay (RIBA) (14%); 3/30 patients with autoimmune chronic active hepatitis, 2/3 by RIBA (7%); 2/50 primary biliary cirrhosis patients, 1/2 by RIBA (2%); 0/30 alcoholic cirrhosis patients; and 2/9 patients with hepatocellular carcinoma, 1/2 by RIBA (11%). HCV is uncommon in North East England; it may be implicated in the aetiology of a minority of cases of cryptogenic liver disease and less than 5% of autoimmune chronic active hepatitis and primary biliary cirrhosis.

HIV infection due to a platelet transfusion after allogeneic bone marrow transplantation.

A 30-yr-old man with chronic granulocytic leukaemia received a bone marrow transplant from his histocompatible sister in December 1982. His post-transplant course was complicated by Grade III graft-versus-host disease and multiple infectious episodes until his death from pneumonia on d + 190. He was later found to be seropositive for anti-HIV at the time of his death. Retrospective analysis of stored sera showed a transient period of seropositivity from d + 11 to d + 20 thought to reflect passive transfer of antibody from a blood product transfused prior to d + 11 when he was also exposed to infectious virus. He remained seronegative until d + 78 when anti-HIV was again found. Seropositivity persisted until his death and was attributed to endogenous antibody response. Although it is unclear whether his clinical course was due to AIDS, exposure of an immunosuppressed patient to HIV may be associated with more rapid development of clinical disease.

The activity of ciprofloxacin and other 4-quinolones against Chlamydia trachomatis and Mycoplasmas in vitro.

Ciprofloxacin was found to be the most active of a group of 4-quinolone antibiotics tested against the SA2f strain of Chlamydia trachomatis (MBC and MIC 1.0 mg/l). Against genital isolates of Chlamydia trachomatis, ciprofloxacin was twice as active as rosoxacin. Ciprofloxacin showed similar activity to that of oxytetracycline against clinical isolates of Mycoplasma hominis and Ureaplasma urealyticum, and was 8-fold more active than rosoxacin against the latter.