Psychological characteristics of Japanese patients and their family members receiving genetic counseling: A single-institute exploratory study.

In Japan, clinical genetic services became available in the 1970s, and genomic medicine, including genetic counseling (GC), developed rapidly. However, research on the outcomes of GC in Japan is limited. Japan has a unique cultural context, and appropriate GC methods have not yet been optimized for this population. The current study aimed to evaluate the psychological status of Japanese patients and their companions undergoing GC and the outcomes of GC. We used the Quality of Care Through the Patients' Eyes-gene cancer (QUOTE-geneCA ), the Genetic Counseling Outcome Scale-24 (GCOS-24), and the State-Trait Anxiety Inventory (STAI) to evaluate patients and their companions' needs and preferences regarding GC, empowerment, and anxiety, respectively. We evaluated stress status during GC by measuring saliva cortisol levels. QUOTE-geneCA results for patients (n = 69) and a group of patients and their companions (n = 96) revealed that participants felt that it was important that skilled medical staff explained medical information and provided advice in an easily understandable manner. Japanese patients and their companions regarded the procedural aspects of counseling as most important and their autonomy in decision-making as less important. GCOS-24 results revealed a significant increase in empowerment scores in 38 patients (by 9.63 points) from pre- to post-GC (p < 0.001; Cohen's d = 0.79). STAI results revealed a significant decrease in state anxiety for patients (6.11 points; p < 0.001; Cohen's d = 0.66). Cortisol levels in patients significantly decreased after GC (p = 0.001). The improvement of empowerment scores from pre- to post-GC among patients and their companions were significantly negatively correlated with pre-GC empowerment scores (p < 0.001), trait anxiety scores (p = 0.001), and the number of people living together (p = 0.011). The change of cortisol levels during GC in patients and their companions was significantly positively correlated with trait anxiety score (p = 0.027). This study suggested that these characteristics of Japanese patients and their companions may predict GC outcomes.

The real-world data on microsatellite instability status in various unresectable or metastatic solid tumors.

Microsatellite instability-high (MSI-H) is an important biomarker for predicting the effect of immune-checkpoint inhibitors (ICIs) on advanced solid tumors. MSI-H is detected in various cancers, but its frequency varies by cancer type and stage. Therefore, precise frequency is required to plan ICIs therapy. In this study, the results of MSI test actually conducted in clinical practice were investigated. In total, 26,469 samples of various cancers were examined to determine if PD-1 blockade was indicated between December 2018 to November 2019. The results of MSI test were obtained for 26,237 (99.1%) among them. The male to female ratio was 51:49 and mean age was 64.3 years. In all the samples, overall frequency of MSI-H was 3.72%. By gender, the frequency of MSI-H was higher in female patients (4.75%) than in male patients (2.62%) (P < 0.001). A comparison by age revealed that the frequency of MSI-H was significantly higher in patients aged less than 40 years (6.12%) and 80 years or older (5.77%) than in patients aged between 60 and 79 years (3.09%) (P < 0.001). MSI-H was detected in 30 cancer types. Common cancer types were endometrial cancer, 16.85%; small intestinal cancer, 8.63%; gastric cancer, 6.74%; duodenal cancer, 5.60%; and colorectal cancer, 3.78%. MSI-H was detected in cancer derived from a wide variety of organs. The frequency of MSI-H varied by cancer types and onset age. These data should prove especially useful when considering ICI treatment. Supporting Information.

Real-world data on microsatellite instability status in various unresectable or metastatic solid tumors.

Microsatellite instability-high (MSI-H) is an important biomarker for predicting the effect of immune checkpoint inhibitors (ICIs) on advanced solid tumors. Microsatellite instability-high is detected in various cancers, but its frequency varies by cancer type and stage. Therefore, precise frequency is required to plan ICI therapy. In this study, the results of MSI tests actually carried out in clinical practice were investigated. In total, 26 469 samples of various cancers were examined between December 2018 and November 2019 to determine whether programmed cell death-1 blockade was indicated. The results of MSI tests were obtained for 26 237 (99.1%) of these samples. The male : female ratio was 51:49 and mean age was 64.3 years. In all samples, the overall frequency of MSI-H was 3.72%. By gender, the frequency of MSI-H was higher in female patients (4.75%) than in male patients (2.62%; P < .001). A comparison by age revealed that the frequency of MSI-H was significantly higher in patients younger than 40 years of age (6.12%) and 80 years or older (5.77%) than in patients aged between 60 and 79 years (3.09%; P < .001). Microsatellite instability-high was detected in 30 cancer types. Common cancer types were: endometrial cancer, 16.85%; small intestinal cancer, 8.63%; gastric cancer, 6.74%; duodenal cancer, 5.60%; and colorectal cancer, 3.78%. Microsatellite instability-high was detected in cancer derived from a wide variety of organs. The frequency of MSI-H varied by cancer type and onset age. These data should prove especially useful when considering ICI treatment.

Cumulative perioperative lymphocyte/C-reactive protein ratio as a predictor of the long-term outcomes of patients with colorectal cancer.

PURPOSE: Systemic inflammatory response influences cancer development and perioperative surgical stress can affect the survival of patients with colorectal cancer (CRC). We developed a system to cumulatively assess perioperative inflammatory response and compare the prognostic value of various cumulative inflammatory and nutritional markers in patients with CRC. METHODS: We assessed perioperative cumulative markers using the trapezoidal area method in 307 patients who underwent surgery for CRC and analyzed the results statistically. RESULTS: The cumulative lymphocyte to C-reactive protein (CRP) ratio (LCR) predicted survival more accurately than other well-established markers (sensitivity: 80.0%, specificity: 69.3%; area under the curve (AUC): 0.779; P < 0.001). A low cumulative LCR was correlated with factors associated with disease development, including undifferentiated histology, advanced T stage, lymph node metastasis, distant metastasis, and advanced TNM stage classification. A decreased cumulative LCR was an independent prognostic factor for both overall survival (OS) (Hazard Ratio (HR):5.21, 95% confidence interval [CI] 2.42-11.2; P < 0.0001) and disease-free survival (DFS) (HR: 1.88, 95% CI 1.07-3.31; P = 0.02), and its prognostic significance was verified in a different clinical setting. The cumulative LCR was correlated negatively with the intraoperative bleeding volume (P < 0.0001, R = -0.4). Combined analysis of cumulative and preoperative LCR could help stratify risk for the oncological outcomes of CRC patients. CONCLUSIONS: The findings of this study demonstrate the value of the cumulative LCR in the postoperative management of patients with CRC.

Japanese Society of Medical Oncology Clinical Guidelines: Molecular Testing for Colorectal Cancer Treatment, 4th edition.

Molecular testing to select the appropriate targeted and standard of care therapies is essential for managing patients with colorectal cancer (CRC). The Japanese Society of Medical Oncology previously published clinical guidelines for molecular testing in CRC. In the third edition published in 2018, RAS and BRAF V600E mutations should be tested prior to first-line chemotherapy to assess the benefit of anti-epidermal growth factor receptor (EGFR) antibody therapy in patients with unresectable CRC. Microsatellite instability (MSI) testing was recommended in patients with curatively resected stage II CRC because deficient mismatch repair is associated with low risk of recurrence. MSI testing was also recommended in patients with CRC suspected to be Lynch syndrome. The main aim of this fourth edition is to reflect recent advances in comprehensive genomic profiling (CGP) tests and liquid biopsy. Here, CGP tests performed on tumor tissues are strongly recommended to assess the benefit of molecular targeted drugs in patients with CRC. Circulating tumor DNA (ctDNA)-based CGP tests are also proposed. ctDNA testing is recommended to determine the optimal treatment based on the risk of recurrence for curatively resected CRC and evaluate the suitability and monitor the therapeutic effects of anti-EGFR antibodies in patients with unresectable CRC. While both MSI testing and immunohistochemistry are strongly recommended to determine the indication of immune checkpoint inhibitors in patients with unresectable CRC, next-generation sequencing-based tests are weakly recommended because these tests have not been validated in clinical trials.

Attitudes toward and current status of disclosure of secondary findings from next-generation sequencing: a nation-wide survey of clinical genetics professionals in Japan.

The management of secondary findings (SFs), which are beyond the intended purpose of the analysis, from clinical comprehensive genomic analysis using next generation sequencing (NGS) presents challenges. Policy statements regarding their clinical management have been announced in Japan and other countries. In Japan, however, the current status of and attitudes of clinical genetics professionals toward reporting them are unclear. We conducted a questionnaire survey of clinical genetics professionals at two time points (2013 and 2019) to determine the enforcement of the SF management policy in cases of comprehensive genetic analysis of intractable diseases and clinical cancer genome profiling testing. According to the survey findings, 40% and 70% of the respondents stated in the 2013 and 2019 surveys, respectively, that they had an SF policy in the field of intractable diseases, indicating that SF policy awareness in Japan has changed significantly in recent years. Furthermore, a total of 80% of respondents stated that their facility had established a policy for clinical cancer genome profiling testing in the 2019 survey. In both surveys, the policies included the selection criteria for genes to be disclosed and the procedure to return SFs, followed by recommendations and proposals regarding SFs in Japan and other countries. To create a better list of the genes to be disclosed, further examination is needed considering the characteristics of each analysis.

Attitudes of clinical geneticists and certified genetic counselors to genome editing and its clinical applications: A nation-wide questionnaire survey in Japan.

Genome editing of the human embryo using CRISPR/Cas9 has the potential to prevent hereditary diseases from being transmitted to the next generation. However, attitudes to this technology have not been examined sufficiently among the genetic professionals who will use it in the near future. We conducted a questionnaire survey of Japanese clinical geneticists and certified genetic counselors. Differences were observed between them in their recognition of this technology and impressions on its difficulty and cost. Both groups worried about misuse of it, with insufficient information and rules. As key elements for such rules, they considered ethics, safety, and purpose. Most disapproved of modifying physical traits as an enhancement, though they hoped for the treatment of severe diseases. At current clinical sites, they tended to adopt a prudent attitude by mentioning only the possibility of genome editing in the future. Academic policies and legislation are required, especially for application in human embryos, through a consensus of professionals and general citizens. Furthermore, professionals should maintain awareness of new developments and regularly reexamine attitudes for the ongoing development of more suitable rules, education systems, and clinical protocols. As preparation for changes, opportunities to address ethical issues and initiate discussions are also required.

Japanese Society of Medical Oncology Clinical Guidelines: Molecular Testing for Colorectal Cancer Treatment, Third Edition.

The Japanese Society of Medical Oncology (JSMO) previously published 2 editions of the clinical guidelines: "Japanese guidelines for testing of KRAS gene mutation in colorectal cancer" in 2008 and "Japanese Society of Medical Oncology Clinical Guidelines: RAS (KRAS/NRAS) mutation testing in colorectal cancer patients" in 2014. These guidelines have contributed to the proper use of KRAS and RAS mutation testing, respectively. Recently, clinical utility, particularly for colorectal cancer (CRC) patients with BRAF V600E mutation or DNA mismatch-repair (MMR) deficiency, has been established. Therefore, the guideline members decided these genetic alterations should also be involved. The aim of this revision is to properly carry out testing for BRAF V600E mutation and MMR deficiency in addition to RAS mutation. The revised guidelines include the basic requirements for testing for these genetic alterations based on recent scientific evidence. Furthermore, because clinical utility of comprehensive genetic testing using next-generation sequencing and somatic gene testing of analyzing circulating tumor DNA has increasingly evolved with recent advancements in testing technology, we noted the current situation and prospects for these testing technologies and their clinical implementation in the revised guidelines.

Comparison of three different anti-Xa assays in major orthopedic surgery patients treated with direct oral anticoagulant.

BACKGROUND: Measurement of edoxaban plasma concentration has been gathering attention in major orthopedic surgery patients receiving edoxaban for the prevention of venous thromboembolism (VTE). METHODS: The anti-Xa activity was measured one hour after edoxaban intake using 3 different assays in 200 patients after major orthopedic surgery. RESULTS: The anti-Xa activities on Day 8 were significantly higher than those on Day 4 and those on Day 4 were significantly higher than those on Day 1. The anti-Xa activities in two assays closely correlated with each other, but the other anti-Xa assay did not correlated with other two assays. The anti-Xa activities as detected in the three Xa assays were significantly higher in the patients without deep vein thrombosis (DVT) than in those with DVT on Day 4. Additionally, there were no significant differences in the anti-Xa activities of assays A, B and C between patients with and without massive bleeding (MB) on Days 1, 4, 8 and 15. CONCLUSION: The results of this study suggest that anti-Xa level could be predictive of the risk of VTE, but not of the risk of massive bleeding.

Ewing Sarcoma of the Bone With EWS/FLI1 Translocation After Successful Treatment of Primary Osteosarcoma.

Although prognosis in patients with localized osteosarcoma has been dramatically improved by the introduction of multiple chemotherapy agents known as combination chemotherapy, there is growing concern about the development of secondary malignant neoplasms. We report the case of a 13-year-old girl in whom the diagnosis of Ewing sarcoma of bone localized on the shaft of left femur was made 2 years after successful treatment without radiotherapy for osteosarcoma of right proximal femur. EWS-FLI1 fusion gene was detected by reverse transcriptase-polymerase chain reaction. To our knowledge, this is the first case with Ewing sarcoma of the bone as a secondary malignant neoplasm developed in osteosarcoma survivor. We collected 15 cases, included this case, with secondary Ewing sarcoma family of tumor by utilizing the PubMed search and might consider the causes of this secondary cancer.

[New Horizon in Clinical Examination -Chairmen's Introductory Remarks -].

Translational research is leading to new technology and generating in practical diagnostic tests with clinical utility. This paper introduces three cutting-edge technologies: liquid biopsy, amino acid profiling, and con- tinuous glucose monitoring (CGM). Liquid biopsy was reviewed as one of the "10 Breakthrough Technologies in 2015" by MIT. This technol- ogy is based on fast DNA-sequencing machines or high-sensitivity PCR and non-invasive tests that detect fragments of DNA or cells in blood or other bodily fluids. Cell-free DNA refers to segments of DNA that are mainly derived from apoptotic and necrotic cells, and it is used for the detection and monitoring of cancer. Profiling of plasma-free amino acid is a promising approach because amino acid profiling links all organ sys- tems and amino acids have important roles in metabolism. Furthermore, amino acid profiles are known to be influenced by specific diseases, including cancers. CGM systems use a tiny sensor inserted under the skin to continuously check glucose levels in tissue fluid and convert blood glucose levels. CGM can provide valuable information at any points during the day and facilitate better treatment decisions and glucose control. [Review].

[Breakthrough Technologies: Liquid Biopsy -Chairmen's Introductory Remarks.]

To date, liquid biopsies have generated much interest as they involve minimally invasive blood tests, pro- vide an ongoing picture of a patient's cancer, and offer valuable insight into the best treatment. Liquid biop- sies detect circulating tumor cells (CTCs), fragments of tumor DNA and exosomes that are shed into the blood from the primary tumor and from metastatic sites. Liquid biopsies offer what tissue biopsies cannot due to risks to the patients and costs. Liquid biopsies allow the monitoring of genomic changes in tumors for the diagnosis of early and recurrent cancer and drug effects. In the future, instead of extensive imaging and invasive tissue biopsies, liquid biopsies could be used to guide cancer treatment decisions and even screen for tumors that are not vet visible on imaging.

Effect of Genetic Polymorphism of CYP3A5 and CYP2C19 and Concomitant Use of Voriconazole on Blood Tacrolimus Concentration in Patients Receiving Hematopoietic Stem Cell Transplantation.

BACKGROUND: Blood tacrolimus (TAC) concentration delivered via intravenous administration is known to be influenced by genetic polymorphism of CYP3A5 and interaction with triazole antifungal agents. However, interindividual variability of blood TAC concentration is as of yet still difficult to predict during the early stages of hematopoietic stem cell transplantation (HSCT). This study was conducted to assess the wide variability of blood TAC concentrations because of the hepatic metabolic activities of CYP3A and CYP2C19 in HSCT recipients. METHODS: This study is a single-institute prospective study that includes 21 adult patients who underwent HSCT and received 24 hours continuous intravenous administration of TAC at the Mie University Hospital between January 2009 and March 2014. After HSCT, the changes in blood TAC concentration/dose (C/D) ratio and TAC dose reduction from initial dose were investigated. RESULTS: Significant differences between HSCT recipients with CYP3A5*1 allele and CYP3A5*3/*3 genotype were observed with respect to the median TAC C/D ratio on day 14 (563 versus 742 ng/mL per mg/kg, P < 0.01) and day 21 (672 versus 777 ng/mL per mg/kg, P < 0.05) after HSCT. Concomitant administration of voriconazole (VRCZ), but not of lansoprazole, was found to significantly increase the median TAC C/D ratio on day 14 (557 versus 723 ng/mL per mg/kg, P < 0.01). Possession of the CYP3A5*3/*3 genotype (day 14: odds ratio, 32.2; day 21: odds ratio, 33.0; P < 0.05) and concomitant administration of VRCZ (day 14: odds ratio, 37.8; P < 0.05) were found to be independent risk factors, which significantly contributed to an increased TAC C/D ratio. In HSCT recipients with CYP3A5*3/*3 genotype (78.0%), the median TAC dose ratio (day 21/day -1) was significantly lower compared with HSCT recipients with the CYP3A5*1 allele (94.1%), whereas VRCZ administration itself had no significant influence. Interestingly, in HSCT recipients with CYP2C19*1/*1, we found that the influence of VRCZ on the TAC dose ratio (85.7%) was relatively mild, even in a recipient with CYP3A5*3/*3. CONCLUSIONS: In HSCT recipients, the variability of intravenous TAC concentration in the blood could be explained in part by the genetic variation of CYP3A5. The study results also strongly imply that the magnitude of hepatic interaction between TAC and VRCZ is affected by the genetic polymorphism of both CYP3A5 and CYP2C19 genes.

[Genomic Tests: From Basic Research to Clinical Practice].

Advanced genomic analytical technologies are developing and challenging the current framework of clinical laboratory testing. However, most genomic tests have been devised as laboratory-developed tests (LDTs) without sufficient validation of their analytical validity. Quality assurance (QA) of tests is mandatory for routine clinical practice. External quality management systems such as ISO add QA. Other than QAs of pre-analysis, analytical procedures, reports, and laboratory personnel should be regularly assessed using appropriate best practices and guidelines for analytical validity. Moreover, ethical, legal, and social issues concerning genomic information should be resolved in genomic tests. Taken together, clinicians and health care policymakers must consider the accuracy with which a test identifies a patient's clinical status and the risks and benefits resulting from test use. Genomic tests in current use vary in terms of their accuracy and potential to improve health outcomes. Recently, high-throughput analysis using next-generation sequencing and microarrays is being developed and introduced into clinical practice. As analysis of these data sets is a huge challenge, it requires novel analytical processes that include data quality assessment, comprehensive analysis, interpretation of the results, and presenting the results to users. Especially, human resources are required to develop genome informatics to interpret large amounts of data. Another issue is to regulate Direct To Consumers (DTC) genetic tests by medical institutions as a salutary health service. Although advanced genomic analytical technologies present some issues, they are useful and powerful tools in clinical practice. Thus, they will be properly introduced into clinical practices in a step by step manner.

[Requirements for Dealing with Personal Genetic Information in Clinical Practice].

As clinical genetics evolves, we must deal with a considerable amount of genetic information in clinical practice. In this review, I mention important requirements for dealing with personal genetic information in medical care. Firstly, quality assurance of molecular genetic testing is required for quality assurance of genetic information. As most labs. have developed "home brew" tests without analytical and clinical validity, the standardization or automation of genetic tests should be developed. If not, it is recommended that genetic tests are performed with the "Best Practice Guideline". Secondly, the confidentiality of genetic information is required because genetic information may be highly predictive of the future health of an individual and have important implications for the relatives of the person tested. For the same reasons, genetic counseling is required following genetic tests. Finally, genetic test results have to be interpreted and a report compiled, which must be easy to understand for physicians and clients. The number of genome bioinformaticians is very limited in Japan, and more must be immediately trained. On dealing with personal genetic information in clinical practice, many issues still remain, and each issue should be steadily resolved.

Evaluation of clinical performance of the major BCR-ABL mRNA detection kit which enables conversion to international standard scale using the reference material calibrator.

In a multicenter study, we evaluated the Major BCR-ABL mRNA/ABL mRNA quantification kit (M135R), which uses reference material included in the kit designed to report results using the international scale (IS). In total, 127 samples were studied. A good correlation was observed between M135R results and home-brew RT-qPCR results, which are reported on the IS using a conversion factor (r=0.90; n=115). However, the correlation coefficient between M135R results and Amp-CML results was relatively low (r=0.56; n=108). A good correlation was observed between M135R results from the two assay sites (r=0.94; n=115). The subset analysis of samples from the two assay sites showed M135R to have a good correlation even in the low IS range (r=0.98; IS≤1%). M135R showed high sensitivity and accuracy for detecting minimal residual disease and is considered to be a useful tool for treatment response assessment and for early detection of recurrence in CML patients.

Practical guide for the diagnosis and management of primary ciliary dyskinesia.

OBJECTIVE: Primary ciliary dyskinesia (PCD) is a relatively rare genetic disorder that affects approximately 1 in 20,000 people. Approximately 50 genes are currently known to cause PCD. In light of differences in causative genes and the medical system in Japan compared with other countries, a practical guide was needed for the diagnosis and management of Japanese PCD patients. METHODS: An ad hoc academic committee was organized under the Japanese Rhinologic Society to produce a practical guide, with participation by committee members from several academic societies in Japan. The practical guide including diagnostic criteria for PCD was approved by the Japanese Rhinologic Society, Japanese Society of Otolaryngology-Head and Neck Surgery, Japanese Respiratory Society, and Japanese Society of Pediatric Pulmonology. RESULTS: The diagnostic criteria for PCD consist of six clinical features, six laboratory findings, differential diagnosis, and genetic testing. The diagnosis of PCD is categorized as definite, probable, or possible PCD based on a combination of the four items above. Diagnosis of definite PCD requires exclusion of cystic fibrosis and primary immunodeficiency, at least one of the six clinical features, and a positive result for at least one of the following: (1) Class 1 defect on electron microscopy of cilia, (2) pathogenic or likely pathogenic variants in a PCD-related gene, or (3) impairment of ciliary motility that can be repaired by correcting the causative gene variants in iPS cells established from the patient's peripheral blood cells. CONCLUSION: This practical guide provides clinicians with useful information for the diagnosis and management of PCD in Japan.

Functional studies of a novel germline p53 splicing mutation identified in a patient with Li-Fraumeni-like syndrome.

Most p53 mutations identified in Li-Fraumeni syndrome (LFS) are missense mutations; splicing mutations have rarely been reported. A novel splicing p53 mutation was identified in a patient with Li-Fraumeni-like syndrome (LFL). Usually, p53 missense mutants identified in LFS and cancer cells function as dominant negative mutations interfering with wild-type p53 function. However, the mechanism by which p53 haploinsufficiency causes carcinogenesis is not well characterized. In this study, we describe a novel splicing mutation that results in the loss-of-function of p53. These findings suggest a linkage between the loss-of-function type p53 mutation and a LFL phenotype.

Kidney-protective effects of azelnidipine versus a diuretic in combination with olmesartan in hypertensive patients with diabetes and albuminuria: a randomized study.

BACKGROUND: A thiazide diuretic used in combination with benazepril is superior to amlodipine plus benazepril in reducing albuminuria in hypertensive patients with diabetes. However, calcium channel blockers have diverse characteristics. Thus, we investigated whether combining an angiotensin receptor blocker with either azelnidipine or a thiazide diuretic produced similar reductions in albuminuria in hypertensive diabetic patients for the same levels of blood pressure achieved. METHODS: Hypertensive patients with type 2 diabetes and albuminuria (30-600 mg/g creatinine) under antihypertensive treatment (mean age 67.0±7.6 years) were instructed to stop all antihypertensive treatment and take a combination of olmesartan (20 mg/day) and amlodipine (5 mg/day) for 3 months (run-in period). Then, patients were randomly assigned to receive either olmesartan plus azelnidipine (16 mg/day; n=71) or olmesartan plus trichlormethiazide (1 mg/day; n=72) for an additional 6 months. The primary end point was urinary excretion of albumin at 6 months after randomization. RESULTS: At the time of randomization, urinary albumin was 116.0 and 107.8 mg/g creatinine (geometric mean) in the azelnidipine and diuretic arms, respectively, and was reduced to a similar extent [79.8 (95% confidence interval 66.4-96.0) and 89.7 (74.6-107.7) mg/g creatinine, respectively, after adjustment for baseline values]. Blood pressure did not differ between the two groups throughout the study period. CONCLUSIONS: Azelnidipine is equally effective as a thiazide diuretic in reducing urinary albumin when used in combination with olmesartan.

Relationship between CYP2C19 loss-of-function polymorphism and platelet reactivities with clopidogrel treatment in Japanese patients undergoing coronary stent implantation.

BACKGROUND: CYP2C19 loss-of-function genotype (*2 and/or *3 alleles) is related to low responsiveness to clopidogrel, which is a risk factor for ischemic cardiac events. The contribution of these genotypes to platelet reactivity in Japanese patients in a steady state receiving dual antiplatelet therapy after coronary stenting was evaluated. METHODS AND RESULTS: A total of 155 Japanese patients were classified according to their CYP2C19 loss-of-function genotype. Platelet reactivity was assayed by plasma levels of soluble P-selectin and platelet-derived microparticles, light transmittance aggregometry induced by ADP (ADP-LTA), shear stress-induced platelet aggregometry, vasodilator-stimulated phosphoprotein phosphorylation (VASP) index and the VerifyNow-P2Y12 assay. Linear and logistic regression models were used to assess the associations between CYP2C19 loss-of-function genotype and high on-treatment platelet reactivity. In total, 62 patients (40.0%) were extensive metabolizers (EMs), 70 (45.2%) were intermediate metabolizers (IMs) and 23 (14.8%) were poor metabolizers (PMs). ADP-specific assays (ADP-LTA, the VASP index and VerifyNow-P2Y12) differed according to CYP2C19 genotype, with a significant gene-dose effect (PMs>IMs>EMs). CYP2C19 loss-of-function carrier status was associated with more frequent high platelet reactivity. CYP2C19 loss-of-function genotype alone could explain 12.2%, 14.3%, and 14.7% of the variability in the ADP-LTA, VASP and VerifyNow-P2Y12 assays, respectively. CONCLUSIONS: CYP2C19 loss-of-function genotype is associated with more frequent high platelet reactivity, as assessed by ADP-specific platelet function tests, in Japanese patients.