Error rate for HLA-B antigen assignment by serology: implications for proficiency testing and utilization of DNA-based typing methods

Until recently, the majority of HLA class I typing has been performed by serology. Expensive commercial typing trays are frequently used for testing non-Caucasian subjects and new strategies using DNA-based methods have been adopted for improving clinical histocompatibility testing results and adapted as supplements in proficiency testing. A double-blind comparison of the typing of HLA-B specificities in 40 samples was carried out between serology and two polymerase chain reaction (PCR) methods, PCR amplification with sequence-specific primers (PCR-SSP) and PCR amplification and subsequent hybridization with sequence-specific oligonucleotide probes (PCR-SSOP). The results demonstrated 22.5% misassignments of HLA-B antigens by serology. There was complete concordance between the results obtained with the two PCR based typing methods. A second panel of 20 donor samples with incomplete or ambiguous serologic results was analyzed by PCR-SSP and SSOP. Both PCR methods identified correctly the HLA-B antigens. Our results suggest that more accurate typing results can be achieved by complementing serologic testing with DNA-based typing techniques. The level of resolution for HLA-B antigen assignment can be obtained by this combination of serology and limited DNA-based typing is equivalent to the HLA-B specificities defined by the WHO-HLA Committee. This level of resolution cannot routinely be achieved in clinical histocompatibility testing or in proficiency testing using serologic reagents only.     

Generation of sheep X (sheep X mouse) heterohybridoma cell line expressing the beta-1 integrin membrane molecule

Sheep are an important biological model in such diverse areas as immunology and reproductive biology. The limitation of sheep as an experimental model is the absence of reliable cell lines. To establish cell lines that express functional sheep membrane molecules, we produced a sheep x mouse heterohybridoma by fusion of sheep efferent lymph T cells with the murine myeloma cell line NS1. A cloned heterohybridoma fusion partner was selected by treatment with 8-azaguanine. The resulting cell line HL1/385 was selected for hypoxanthine/aminopterin/thymidine (HAT) sensitivity and growth efficiency. The HL1/385 cell line was used as a back-fusion partner into lectin-stimulated efferent T lymphocytes. The back-fusion approach produced more than 50 heterohybrid cell lines with high growth efficiency. The expression of physiological levels of the sheep beta-1 integrin cell surface molecule on the HT4/6 cell line was stable for months in culture. These results suggest that somatic heterohybrids may provide a reliable source of cell lines for sheep studies in vitro.     

A Systematic Review of the Evidence for the Decipher Genomic Classifier in Prostate Cancer

ContextMolecular biomarkers aim to address the established limitations of clinicopathologic factors to accurately risk stratify patients with prostate cancer (PCa). Questions remain as to whether sufficient evidence supports adoption of these biomarkers for clinical use.ObjectiveTo perform a systematic review of the available evidence supporting the clinical utility of the Decipher genomic classifier (GC).Evidence acquisitionThe review was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines by searching PubMed and conference abstracts from January 2010 to June 2020. Evidence was then graded using the criteria of Simon et al (Simon RM, Paik S, Hayes DF. Use of archived specimens in evaluation of prognostic and predictive biomarkers. J Natl Cancer Inst 2009;101:1446–52) and American Urology Association (AUA) criteria.Evidence synthesisIn total, 42 studies and 30 407 patients were included. GC performance data were available for localized, postprostatectomy, nonmetastatic castration-resistant, and metastatic hormone-sensitive PCa as part of retrospective studies (n = 12 141), prospective registries (n = 17 053), and prospective and post hoc randomized trial analyses (n = 1213). In 32 studies (n = 12 600), the GC was independently prognostic for all study endpoints (adverse pathology, biochemical failure, metastasis, and cancer-specific and overall survival) on multivariable analysis and improved the discrimination over standard of care in 24 studies (n = 8543). GC use changed the management in active surveillance (number needed to test [NNT] = 9) and postprostatectomy (NNT = 1.5–4) settings in five studies (n = 4331). Evidence strength was levels 1 and 2 by the Simon criteria for all disease states other than high-risk PCa, and grades A and B by AUA criteria depending on disease state.ConclusionsConsistent data are now present from diverse levels of evidence, which when viewed together, have demonstrated clinical utility of the GC in PCa. The utility of the GC is strongest for intermediate-risk PCa and postprostatectomy decision-making.Patient summaryIn this paper, we review the evidence of the Decipher genomic classification tool for men with prostate cancer. We found consistent evidence that the test helps identify which cancers are more or less aggressive, which in turn aids in personalized treatment decision-making.     

Efficacy and Safety of Atezolizumab Plus Bevacizumab Following Disease Progression on Atezolizumab or Sunitinib Monotherapy in Patients with Metastatic Renal Cell Carcinoma in IMmotion150: A Randomized Phase 2 Clinical Trial

BackgroundThe use of immune checkpoint inhibitors combined with vascular endothelial growth factor (VEGF)-targeted therapy as second-line treatment for metastatic clear cell renal cancer (mRCC) has not been evaluated prospectively.ObjectiveTo evaluate the efficacy and safety of atezolizumab + bevacizumab following disease progression on atezolizumab or sunitinib monotherapy in patients with mRCC.Design, setting, and participantsIMmotion150 was a multicenter, randomized, open-label, phase 2 study of patients with untreated mRCC. Patients randomized to the atezolizumab or sunitinib arm who had investigator-assessed progression as per RECIST 1.1 could be treated with second-line atezolizumab + bevacizumab.InterventionPatients received atezolizumab 1200 mg intravenously (IV) plus bevacizumab 15 mg/kg IV every 3 wk following disease progression on either atezolizumab or sunitinib monotherapy.Outcome measurements and statistical analysisThe secondary endpoints analyzed during the second-line part of IMmotion150 included objective response rate (ORR), progression-free survival (PFS), and safety. PFS was examined using Kaplan-Meier methods.Results and limitationsFifty-nine patients in the atezolizumab arm and 78 in the sunitinib arm were eligible, and 103 initiated second-line atezolizumab + bevacizumab (atezolizumab arm, n = 44; sunitinib arm, n = 59). ORR (95% confidence interval [CI]) was 27% (19–37%). The median PFS (95% CI) from the start of second line was 8.7 (5.6–13.7) mo. The median event follow-up duration was 19.4 (12.9–21.9) mo among the 25 patients without a PFS event. Eighty-six (83%) patients had treatment-related adverse events; 31 of 103 (30%) had grade 3/4 events. Limitations were the small sample size and selection for progressors.ConclusionsThe atezolizumab + bevacizumab combination had activity and was tolerable in patients with progression on atezolizumab or sunitinib. Further studies are needed to investigate sequencing strategies in mRCC.Patient summaryPatients with advanced kidney cancer whose disease had worsened during treatment with atezolizumab or sunitinib began second-line treatment with atezolizumab + bevacizumab. Tumors shrank in more than one-quarter of patients treated with this combination, and side effects were manageable.     

Factors Associated with Nodal Pathologic Complete Response Among Breast Cancer Patients Treated with Neoadjuvant Chemotherapy: Results of CALGB 40601 (HER2+) and 40603 (Triple-Negative) (Alliance)

Annals of Surgical Oncology - De-escalation of axillary surgery after neoadjuvant chemotherapy (NAC) requires careful patient selection. We seek to determine predictors of nodal pathologic complete...     

Antitumor alkylating agents: in vitro cross-resistance and collateral sensitivity studies

Cell lines resistant to five antitumor alkylating agents (CDDP, PAM, 4-HC, HN2, and BCNU) were developed from five parental human tumor lines representative of solid tumors with a range of sensitivities to antitumor alkylating agents. The parental cell lines were SCC-25 squamous carcinoma of the head and neck, MCF-7 breast carcinoma, SW2 small-cell lung cancer, SL6 non-small-cell lung carcinoma, and G3361 melanoma. Survival curves using colony formation as the endpoint were generated for each of the 25 cell lines to each of the five alkylating agents. Comparison of the drug concentrations that reduced the survival of the alkylating agent-resistant cell lines by 90% (IC₉₀ values) with the IC₉₀ values obtained for the corresponding parental cell lines was used as a measure of the resistance/sensitivity of the alkylating agent-resistant lines to each drug tested. Although cross-resistance among the alkylating agents was generally uncommon, several patterns of response emerged. Cross-resistance occurred in 27 of the 105 determinations and occurred most frequently in the cell lines in which resistance was developed to PAM (57%) or BCNU (38%). Cross-resistance to HN2 occurred most frequently. Collateral sensitivity was equally as common, occurring in 25 of the 105 determinations. Collateral sensitivity occurred most frequently in the cell lines made resistant to 4-HC. The 4-HC-resistant cell lines were most frequently collaterally sensitive to PAM and to BCNU. Cross-resistance developed most frequently in the MCF-7 breast carcinoma and SCC-25 squamous-cell carcinoma cell lines, whereas collateral sensitivity developed most frequently in the SW2 small-cell lung cancer line and the G3361 melanoma cell line and least frequently in the MCF-7 breast carcinoma cell line and the SL6 non-small-cell lung cancer cell line. The implication of these findings for the development of strategies for clinical treatment are discussed.Abbreviations AAs antitumor alkylating agents - CDDP cisplatin,cis-diamminedichloroplatinum(II) - HN2 nitrogen mustard - BCNU N,N-bis(2-chloroethyl)-N-nitrosourea - PAM l-phenylalanine mustard, melphalan - 4-HC 4-hydroxyperoxycyclophosphamide - CPA cyclophosphamide - THIO trimethyleneiminethiophosphoramide - DME Dulbecco's modified Eagle's medium - IC₉₀ 90% inhibitory concentration - PBS phosphate-buffered 0.9% saline - FBS fetal bovine serum - GSH glutathione - GST glutathione-S-transferase This work was supported by NIH grant PO1-38493, by a grant from the Mathers Foundation, by a grant from Bristol-Myers-Squibb, Inc., Wallingford, Connecticut, and by ACS grant CH-487