Clinical Validation of Plasma-Based Genotyping for RAS and BRAF V600E Mutation in Metastatic Colorectal Cancer: SCRUM-Japan GOZILA Substudy.

PURPOSE: Circulating tumor DNA (ctDNA) genotyping on the basis of next-generation sequencing (NGS) may guide targeted therapy for metastatic colorectal cancer (mCRC). However, the validity of NGS-based ctDNA genotyping for RAS/BRAF V600E mutation assessment and the efficacy of anti-EGFR and BRAF-targeted therapies on the basis of ctDNA results remains unclear. PATIENTS AND METHODS: The performance of NGS-based ctDNA genotyping for RAS/BRAF V600E mutation assessment was compared with that of a validated polymerase chain reaction-based tissue testing in patients with mCRC enrolled in the GOZILA study, a nationwide plasma genotyping study. The primary end points were concordance rate, sensitivity, and specificity. The efficacy of anti-EGFR and BRAF-targeted therapies on the basis of ctDNA were also evaluated. RESULTS: In 212 eligible patients, the concordance rate, sensitivity, and specificity were 92.9% (95% CI, 88.6 to 96.0), 88.7% (95% CI, 81.1 to 94.0), and 97.2% (95% CI, 92.0 to 99.4) for RAS and 96.2% (95% CI, 92.7 to 98.4), 88.0% (95% CI, 68.8 to 97.5), and 97.3% (95% CI, 93.9 to 99.1) for BRAF V600E, respectively. In patients with a ctDNA fraction of ≥1.0%, sensitivity rose to 97.5% (95% CI, 91.2 to 99.7) and 100% (95% CI, 80.5 to 100.0) for RAS and BRAF V600E mutations, respectively. In addition to a low ctDNA fraction, previous chemotherapy, lung and peritoneal metastases, and interval between dates of tissue and blood collection were associated with discordance. The progression-free survival of anti-EGFR therapy and BRAF-targeted treatment was 12.9 months (95% CI, 8.1 to 18.5) and 3.7 (95% CI, 1.3 to not evaluated) months, respectively, for matched patients with RAS/BRAF V600E results by ctDNA. CONCLUSION: ctDNA genotyping effectively detected RAS/BRAF mutations, especially with sufficient ctDNA shedding. Clinical outcomes support ctDNA genotyping for determining the use of anti-EGFR and BRAF-targeted therapies in patients with mCRC.

Clinical Validity of Plasma-Based Genotyping for Microsatellite Instability Assessment in Advanced GI Cancers: SCRUM-Japan GOZILA Substudy.

PURPOSE: Circulating tumor DNA (ctDNA) genotyping may guide targeted therapy for patients with advanced GI cancers. However, no studies have validated ctDNA genotyping for microsatellite instability (MSI) assessment in comparison with a tissue-based standard. PATIENTS AND METHODS: The performance of plasma-based MSI assessment using Guardant360, a next-generation sequencing-based ctDNA assay, was compared with that of tissue-based MSI assessment using a validated polymerase chain reaction-based method in patients with advanced GI cancers enrolled in GOZILA study, a nationwide ctDNA profiling study. The primary end points were overall percent agreement, positive percent agreement (PPA), and negative percent agreement. The efficacy of immune checkpoint inhibitor therapy was also evaluated. RESULTS: In 658 patients with advanced GI cancers who underwent both plasma and tissue testing for MSI, the overall percent agreement, PPA, and negative percent agreement were 98.2% (95% CI, 96.8 to 99.1), 71.4% (95% CI, 47.8 to 88.7), and 99.1% (95% CI, 98.0 to 99.7), respectively. In patients whose plasma samples had a ctDNA fraction ≥ 1.0%, the PPA was 100.0% (15/15; 95% CI, 78.2 to 100.0). Three patients with MSI-high (MSI-H) tumors detected only by ctDNA genotyping achieved clinical benefits after receiving anti-programmed cell death 1 therapy with the progression-free survival ranging from 4.3 to 16.7 months. One patient with an aggressive cancer of an unknown primary site benefited from pembrolizumab after rapid detection of MSI-H by ctDNA genotyping. CONCLUSION: ctDNA genotyping was able to detect MSI with high concordance to validated tissue-based MSI testing, especially in patients with tumors that have sufficient ctDNA shedding. Furthermore, ctDNA genotyping enabled identification of patients with MSI-H tumors who benefited from immune checkpoint inhibitor treatment.

Critical function of Prdm14 for the establishment of the germ cell lineage in mice.

Specification of germ cell fate is fundamental in development and heredity. Recent evidence indicates that in mice, specification of primordial germ cells (PGCs), the common source of both oocytes and spermatozoa, occurs through the integration of three key events: repression of the somatic program, reacquisition of potential pluripotency and ensuing genome-wide epigenetic reprogramming. Here we provide genetic evidence that Prdm14, a PR domain-containing transcriptional regulator with exclusive expression in the germ cell lineage and pluripotent cell lines, is critical in two of these events, the reacquisition of potential pluripotency and successful epigenetic reprogramming. In Prdm14 mutants, the failure of these two events manifests even in the presence of Prdm1 (also known as Blimp1), a key transcriptional regulator for PGC specification. Our combined evidence demonstrates that Prdm14 defines a previously unknown genetic pathway, initiating independently from Prdm1, for ensuring the launching of the mammalian germ cell lineage.

[Efficacy of nurses' on the job training to better advise cessation among hospitalized smokers].

OBJECTIVES: The article describes the framework of an on-the-job training program for nurses that teaches them how to better advise hospitalized smokers to stop smoking. The purpose of the study was to evaluate the efficacy of the program. METHODS: We corducted an on-the-job training program for 4 years aimed at nurses who worked in 2 of 11 wards in our hospital (training wards). The aim of the training program that we developed was to improve nurses' self-efficacy in advising and supporting patients to stop smoking. An average of 40 nurses worked in the two wards at any time during the study period. A self-administered questionnaire was given to nurses working at our hospital before (in 1997) and after (in 2002) the program was undertaken. Changes in cognition and behavior with regard to advice to hospitalized smokers were also compared between nurses working at the training wards and nurses working in the other wards in question, whose number averaged 200 nurses during the period. RESULTS: There were no differences in age distribution, smoking habits and epidemiological knowledge of smoking between the two groups. Self-efficacy in advising and supporting patients to cease smoking was significantly increased among nurses working in the training wards (P=0.02), whereas no significant increase with time was found among nurses working in the other wards (P=0.14). After the program was undertaken, nurses working in the training wards had a significantly higher proportion who always advised hospital smokers to quit according to their predictable stage of change than their counter parts working in the other wards (adjusted odds ratio 2.93, 95% confidence interval 1.27-6.74). CONCLUSION: The study indicates the job training program to have improved the nurses' self-efficacy, appearing to change their behavior in advising and supporting patients to cease smoking.

Mutational analysis of Pyrococcus furiosus replication factor C based on the three-dimensional structure.

In eukaryotic DNA replication, replication factor C (RFC) acts as a "clamp loader" that loads PCNA onto a primed DNA template in an ATP-dependent manner. Proteins with functions essentially identical to that of RFC exist in Archaea. We have determined the crystal structure of the small subunit (RFCS) of Pyrococcus furiosus RFC at 2.8-A resolution. Using the information from the determined tertiary structure, we prepared several mutations in RFCS and biochemically characterized them. Truncation of the C-terminal alpha-helix (alpha16) causes a failure in RFCS oligomerization and a loss of the stimulating activity for the PCNA-dependent DNA synthesis by DNA polymerases. The site-directed reduction of the negative charges at the center part of the RFCS complex affected the stability of the RFC-PCNA interaction and reduced the clamp-loading activity. These results contribute to our general understanding of the structure-function relationship of the RFC molecule for the clamp-loading event.