ABSTRACT
BACKGROUND & AIMS: Patients with bi-allelic germline mutations in mismatch repair (MMR) genes (MLH1, MSH2, MSH6, or PMS2) develop a rare but severe variant of Lynch syndrome called constitutional MMR deficiency (CMMRD). This syndrome is characterized by early-onset colorectal cancers, lymphomas or leukemias, and brain tumors. There is no satisfactory method for diagnosis of CMMRD because screens for mutations in MMR genes are noninformative for 30% of patients. MMR-deficient cancer cells are resistant to genotoxic agents and have microsatellite instability (MSI), due to accumulation of errors in repetitive DNA sequences. We investigated whether these features could be used to identify patients with CMMRD. METHODS: We examined MSI by PCR analysis and tolerance to methylating or thiopurine agents (functional characteristics of MMR-deficient tumor cells) in lymphoblastoid cells (LCs) from 3 patients with CMMRD and 5 individuals with MMR-proficient LCs (controls). Using these assays, we defined experimental parameters that allowed discrimination of a series of 14 patients with CMMRD from 52 controls (training set). We then used the same parameters to assess 23 patients with clinical but not genetic features of CMMRD. RESULTS: In the training set, we identified parameters, based on MSI and LC tolerance to methylation, that detected patients with CMMRD vs controls with 100% sensitivity and 100% specificity. Among 23 patients suspected of having CMMRD, 6 had MSI and LC tolerance to methylation (CMMRD highly probable), 15 had neither MSI nor LC tolerance to methylation (unlikely to have CMMRD), and 2 were considered doubtful for CMMRD based on having only 1 of the 2 features. CONCLUSION: The presence of MSI and tolerance to methylation in LCs identified patients with CMMRD with 100% sensitivity and specificity. These features could be used in diagnosis of patients.
Subject(s)
Antineoplastic Agents, Alkylating/therapeutic use , Biomarkers, Tumor/genetics , Brain Neoplasms/diagnosis , Colorectal Neoplasms, Hereditary Nonpolyposis/diagnosis , Colorectal Neoplasms/diagnosis , Drug Resistance, Neoplasm , Genetic Testing , Germ-Line Mutation , Lymphocytes/drug effects , Microsatellite Instability , Neoplastic Syndromes, Hereditary/diagnosis , Adaptor Proteins, Signal Transducing/genetics , Adenosine Triphosphatases/genetics , Adult , Brain Neoplasms/drug therapy , Brain Neoplasms/genetics , Brain Neoplasms/metabolism , Brain Neoplasms/pathology , Caco-2 Cells , Case-Control Studies , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Colorectal Neoplasms, Hereditary Nonpolyposis/drug therapy , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Colorectal Neoplasms, Hereditary Nonpolyposis/metabolism , Colorectal Neoplasms, Hereditary Nonpolyposis/pathology , DNA Mutational Analysis , DNA Repair Enzymes/genetics , DNA-Binding Proteins/genetics , Female , Genetic Predisposition to Disease , Genetic Testing/methods , HCT116 Cells , Heredity , Humans , Lymphocytes/metabolism , Male , Methylation , Mismatch Repair Endonuclease PMS2 , Multiplex Polymerase Chain Reaction , MutL Protein Homolog 1 , MutS Homolog 2 Protein/genetics , Neoplastic Syndromes, Hereditary/drug therapy , Neoplastic Syndromes, Hereditary/genetics , Neoplastic Syndromes, Hereditary/metabolism , Neoplastic Syndromes, Hereditary/pathology , Nuclear Proteins/genetics , Phenotype , Predictive Value of Tests , Reproducibility of Results , Transfection , Young AdultSubject(s)
Comprehensive Health Care/organization & administration , Cooperative Behavior , Interdisciplinary Communication , Internationality , Surgical Procedures, Operative , Telemedicine/organization & administration , Comprehensive Health Care/economics , Comprehensive Health Care/trends , Computer Communication Networks/economics , Computer Communication Networks/organization & administration , Computer Communication Networks/trends , Cost Savings/economics , Cost Savings/trends , Emergency Service, Hospital/economics , Emergency Service, Hospital/organization & administration , Emergency Service, Hospital/trends , Germany , Hospitals, University/economics , Hospitals, University/organization & administration , Hospitals, University/trends , Humans , Quality Improvement/economics , Quality Improvement/organization & administration , Quality Improvement/trends , Surgical Procedures, Operative/economics , Surgical Procedures, Operative/trends , Telemedicine/economics , Telemedicine/trends , Telemetry/economics , Telemetry/trends , Teleradiology/economics , Teleradiology/organization & administration , Teleradiology/trends , Wounds and Injuries/surgeryABSTRACT
BACKGROUND: Antibiotic treatment of community-acquired pneumonia (CAP) in children remains mostly empirical because clinical and paraclinical findings poorly discriminate the principal causes of CAP. Fast response to beta-lactam treatment can be considered a proxy of pneumococcal aetiology. We aimed to identify the best biological predictor of response to beta-lactam therapy in children hospitalized for CAP. METHODS: A retrospective, single-centre cohort study included all consecutive patients 1 month to 16 years old hospitalized in a teaching hospital in Paris, France, because of CAP empirically treated with a beta-lactam alone from 2003 to 2010. Uni- and multivariate analyses were used to study the ability of routine biological parameters available in the Emergency Department to predict a favourable response to beta-lactam (defined as apyrexia within 48 hours of treatment onset). RESULTS: Among the 125 included patients, 85% (106) showed a favourable response to beta-lactam. In multivariate logistic regression, we found procalcitonin (PCT) the only independent predictor of apyrexia (p = 0.008). The adjusted odds ratio for the decadic logarithm of PCT was 4.3 (95% CI 1.5-12.7). At ≥ 3 ng/mL, PCT had 55.7% sensitivity (45.7-65.3), 78.9% specificity (54.4-93.9), 93.7% positive predictive value (84.5-98.2), 24.2% negative predictive value (14.2-36.7), 2.64 positive likelihood ratio (1.09-6.42) and 0.56 negative likelihood ratio (0.41-0.77). In the 4 children with a PCT level ≥ 3 ng/mL and who showed no response to beta-lactam treatment, secondary pleural effusion had developed in 3, and viral co-infection was documented in 1. CONCLUSIONS: PCT is the best independent biologic predictor of favourable response to beta-lactam therapy in children hospitalized for CAP. Thus, a high PCT level is highly suggestive of pneumococcal aetiology. However, a 3-ng/mL cut-off does not seem compatible with daily medical practice, and additional research is needed to further define the role of PCT in managing CAP in children.
