Exosome-Based Detection of EGFR T790M in Plasma from Non-Small Cell Lung Cancer Patients

Purpose: About 60% of non-small cell lung cancer (NSCLC) patients develop resistance to targeted epidermal growth factor receptor (EGFR) inhibitor therapy through the EGFR T790M mutation. Patients with this mutation respond well to third-generation tyrosine kinase inhibitors, but obtaining a tissue biopsy to confirm the mutation poses risks and is often not feasible. Liquid biopsies using circulating free tumor DNA (cfDNA) have emerged as a noninvasive option to detect the mutation; however, sensitivity is low as many patients have too few detectable copies in circulation. Here, we have developed and validated a novel test that overcomes the limited abundance of the mutation by simultaneously capturing and interrogating exosomal RNA/DNA and cfDNA (exoNA) in a single step followed by a sensitive allele-specific qPCR.Experimental Design: ExoNA was extracted from the plasma of NSCLC patients with biopsy-confirmed T790M-positive (N = 102) and T790M-negative (N = 108) samples. The T790M mutation status was determined using an analytically validated allele-specific qPCR assay in a Clinical Laboratory Improvement Amendment laboratory.Results: Detection of the T790M mutation on exoNA achieved 92% sensitivity and 89% specificity using tumor biopsy results as gold standard. We also obtained high sensitivity (88%) in patients with intrathoracic disease (M0/M1a), for whom detection by liquid biopsy has been particularly challenging.Conclusions: The combination of exoRNA/DNA and cfDNA for T790M detection has higher sensitivity and specificity compared with historical cohorts using cfDNA alone. This could further help avoid unnecessary tumor biopsies for T790M mutation testing. Clin Cancer Res; 24(12); 2944-50. ©2018 AACR.

Abstract LB-B03: Exosome-based Detection of EGFR T790M in Plasma from Non-Small Cell Lung Cancer Patients

About 60% of non-small cell lung cancer (NSCLC) patients develop resistance to targeted epidermal growth factor receptor (EGFR) inhibitor therapy through the EGFR T790M mutation. Although these patients respond well to third generation tyrosine kinase inhibitors like osimertinib, obtaining tissue biopsies for mutation profiling poses risks and is often not feasible. Detecting the mutation in a liquid biopsy from plasma has emerged as a viable alternative to biopsy, however existing liquid biopsy tests using cell-free DNA (cfDNA) often suffer from low sensitivity due to the low copy number of mutant molecules in circulation. As an example, the Food and Drug Adminstration (FDA) approved companion diagnostic for T790M mutation status in plasma (cobas® EGFR mutation Test version 2) only has a 58% sensitivity at a specificity of 80%. In this study we aimed to achieve a higher performance by combining the mutated alleles on cfDNA as well as exosomal RNA and DNA (exoNA) .

ExoNA and cfDNA were extracted from the plasma of NSCLC patients with biopsy-confirmed T790M-positive (N = 102) or T790M-negative (N = 108) samples. The T790M mutation status in plasma exoNA and cfDNA was determined using an analytically validated allele-specific qPCR assay in a CLIA laboratory.

The training cohort consisted of 105 samples (51 positives, 54 negatives). The validation cohort consisted of 105 samples (51 positives, 54 negatives), where ~40% of the patients had intrathoracic disease(M0/M1a). Detection of the T790M mutation in exoNA and cfDNA achieved 92% sensitivity and 89% specificity when compared to tumor biopsy results in the validation cohort. We also observed a very high sensitivity (88%) in patients with intrathoracic disease (M0/M1a), patients for whom detection by liquid biopsy has been proven particularly challenging.

The combination of exoNA and cfDNA for EGFR T790M detection has a higher sensitivity and specificity compared to historical cohorts using ctDNA alone. This is especially important as it could aid giving the right treatment to patients where biopsy is not available or avoid unnecessary tumor biopsies for T790M mutation testing.

Citation Format: Elena Castellanos, Dominik G. Grimm, Vasisht Tadigotla, Stefan Bentink, James Hurley, John Healy, Patricia L. Neal, Mia Sher, Dan Baughman, Chris Karlovich, Mitch Raponi, Anne Krug, Mikkel Noerholm, Luis E. Raez, Johan Skog. Exosome-based Detection of EGFR T790M in Plasma from Non-Small Cell Lung Cancer Patients [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-B03.

Genetic heterogeneity in Pakistani microcephaly families revisited

Autosomal recessive primary microcephaly (MCPH) is a rare and heterogeneous genetic disorder characterized by reduced head circumference, low cognitive prowess and, in general, architecturally normal brains. As many as 14 different loci have already been mapped. We recruited 35 MCPH families in Pakistan and could identify the genetic cause of the disease in 31 of them. Using homozygosity mapping complemented with whole-exome, gene panel or Sanger sequencing, we identified 12 novel mutations in 3 known MCPH-associated genes - 9 in ASPM, 2 in MCPH1 and 1 in CDK5RAP2. The 2 MCPH1 mutations were homozygous microdeletions of 164,250 and 577,594 bp, respectively, for which we were able to map the exact breakpoints. We also identified four known mutations - three in ASPM and one in WDR62. The latter was initially deemed to be a missense mutation but we demonstrate here that it affects splicing. As to ASPM, as many as 17 out of 27 MCPH5 families that we ascertained in our sample were found to carry the previously reported founder mutation p.Trp1326*. This study adds to the mutational spectra of four known MCPH-associated genes and updates our knowledge about the genetic heterogeneity of MCPH in the Pakistani population considering its ethnic diversity.

Formulation and evaluation of mouth disintegrating tablets of atenolol and atorvastatin

In this study, mouth-disintegrating tablets of atenolol and atorvastatin combination were formulated using superdisintegrants to impart fast disintegration. Fifteen formulations were prepared based on different concentrations of two superdisintegrants, croscarmellose sodium and Kyron-T₁₃₄. Three different techniques such as direct compression, effervescent and sublimation were used to study the effect of manufacturing processes, nature and concentration of superdisintegrants on various features of these tablets. Five formulations were made using each method. Precompression studies like bulk density, tapped density, angle of repose, Carr's compressibility index, Hausner's ratio and compatibility studies such as Fourier transform infrared spectroscopy and differential scanning calorimetry were performed. Various features such as hardness, thickness, diameter, weight variation, friability, disintegration time, dissolution studies, wetting time, wetting volume, water absorption ratio, modified disintegration, uniformity of contents and stability were evaluated. Finally results were statistically analyzed by the application of one way ANOVA test. Formulation F₁₃ containing Kyron-T₁₃₄ (6%) and croscarmellose sodium (2%) was found to be the best among all fifteen formulations prepared in all aspects evaluated. Sublimation method is found to be the best among three methods of preparation used.

Pharmacokinetic study of a new derivative of sulfamethoxazole

The study was aimed at determination of pharmacokinetic parameters of a previously synthesized salicylidine-sulfamethoxazole-Zn(II) monohydrate in normal humans. This new derivative of sulfamethoxazole was reported to be more active and less toxic than the parent drug by our group. 10 volunteers received a 200 mg dose of the drug orally. Blood samples were collected just before and after 0.16, 0.33, 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0 and 8.0 h of administration of the drug. The plasma samples were analyzed for sulfamethoxazole by a new validated high performance liquid chromatography method having a suitable limit of quantification. The dose of each drug was well tolerated without any adverse effect. The maximum plasma sulfamethoxazole concentration was 280 μg L - 1 at a tmax 1.30 h. This suggests a rapid onset effect of the complex as compared with the parent drug. The plasma half-life, clearance, and volume of distribution of sulfamethoxazole from salicylidine-sulfamethoxazole-Zn(II) monohydrate were 1.64 h, 0.24 L h - 1 and 0.57 L kg - 1 respectively. The elimination of sulfamethoxazole followed the first order kinetics with R2>0.984. The larger value of volume of distribution and clearance for the new derivative, as compared to that of the parent drug, show that the new derivative may exhibit prolonged antimicrobial effect with rapid clearance.

Large electric dipole moments of heavy leptons

In many models of CP violation, the electric dipole moment (EDM) of a heavy charged or neutral lepton could be very large. In models in which the EDMs scale as the cube of the mass, as well as in vectorlike models, a 100 GeV heavy lepton can have an EDM as large as 0.01e fermi. This could dominate the electromagnetic properties of heavy leptons. The angular distribution and production cross section of charged and neutral heavy leptons with large EDMs is calculated and discussed. The interesting possibility that a heavy neutrino with a large EDM could leave an ionization track in a drift chamber is investigated.

The nonoperative management of fistula-in-ano

BACKGROUND/PURPOSE

Fistulotomy is the accepted treatment for infants with perianal fistula. Although recurrence rates range from 0% to 68%. Based on the experience of a senior colleague who noted that babies suffering from perianal fistula follow a self-limited course the authors decided to determine if this observation was accurate.

METHODS

A conservative approach to perianal abscess and fistula was used prospectively in 18 male infants. Abscesses were to be drained only if the baby was very uncomfortable or febrile. Once a fistula developed the authors continued observation until the fistula healed. Data are expressed as mean +/- SD. Mean follow-up period was 37 months.

RESULTS

Mean age at onset of symptoms was 4 +/- 3 months. Fistulas developed in 14 patients (77%). All fistulas healed without operation. Four patients had abscesses drained for discomfort (n = 3) or fever (n = 1). No patient required antibiotics. Mean duration of symptoms was 6 +/- 4 months. Four patients in whom fistulas did not form healed after incision (n = 3) or spontaneous drainage (n = 1). All patients currently are asymptomatic.

CONCLUSIONS

In healthy neonates, perianal abscess and fistula are self-limited conditions rarely requiring surgical drainage and not requiring antibiotics. The conservative management of perianal abscess and fistula in healthy infants appears to be safe and effective.

Shade selection. Communicating with the laboratory technician

Shade selection for anterior crowns has always set up a communications problem between the dentist and laboratory technician. Over the years, many different techniques have been formulated to help overcome the problem. These techniques include picture taking, drawing diagrams and using multiple porcelain shade guides. However, they have not completely erased the difficulty of communicating the choice of the proper shade of an anterior crown. This was especially true in the 1990's when all-ceramic crowns were introduced. Popular techniques dentists use for communicating shade selections will be reviewed, along with guidelines for making the proper selection. Many dentists are familiar only with the techniques they were taught in dental school and/or residency program and are unaware of the superior methods that can be used. This type of review can be extremely helpful to restorative dentists.

What's behind your smile?

Dentistry in the 1990s has seen an evolution in new cosmetic materials and techniques. In order to appreciate and use these methods and materials properly, it is important to have an understanding of cosmetic dentistry and its origins. This article gives a brief history of esthetic dentistry and guidelines for cosmetic dentists of the future.

Laparoscopic colorectal surgery. Do we get faster?

BACKGROUND

A variety of parameters can affect the outcome of laparoscopic colorectal surgery. All consecutive laparoscopic colorectal procedures (LCP) were analyzed in an attempt to define an operative time curve for different categories of procedures. Additionally, impacts of case number and procedure type on length of procedure were assessed.

METHODS

Our computerized data system was reviewed for all patients who underwent LCP in a 4-year period. Parameters reviewed included age, sex, surgical indications, procedures performed, length of procedure, intraoperative and postoperative complications, incidence and causes for conversion, duration of postoperative ileus, and hospital stay.

RESULTS

Between August 1991 and December 1995, 175 patients with a mean age of 48.4 (range 15-88) years underwent LCP. Patients were divided chronologically into five consecutive groups. Procedures were classified as either basic or complex. Complex procedures were those in which there was either a fixed tumor, an abscess or fistula, or extensive intraabdominal adhesions from prior surgery. Complex procedures performed each year ranged from 37% to 66%. As well, the percentage of patients with adhesions increased from 17% in 1991 to 29% in 1995. Despite increased difficulty, the intraoperative complication rate fell significantly from 29% in 1991 to 8% in 1995 (p < 0.005). Additionally, the operative length decreased from a mean of 201 min in 1991 to a mean of 141 min in 1995 (p < 0.05).

CONCLUSION

The rapid improvement in these parameters may reflect both ascents in the learning curve and change in type of procedure. Adhesions, due to prior surgery or inflammation making dissection tedious, is the most important technical factor which effects operation time (p < 0.001). However, despite increased complexity, operating time decreased, reflecting improved skills. Thus, the experienced laparoscopic surgeon can increase the spectrum of applications with expectations of shorter operations and lower complication rates.

The laryngeal mask airway: a new technique for fiberoptic guided vocal cord biopsy

STUDY OBJECTIVE

To describe a new technique for vocal cord biopsy involving placement of a laryngeal mask airway (LMA) during general anesthesia and fiberoptic guided biopsy. To report our early experience with this technique.

DESIGN

Descriptive study.

SETTING

Teaching hospital.

PATIENTS

10 patients undergoing vocal cord biopsy for minor laryngeal pathology and with no evidence of infraglottic airway obstruction.

INTERVENTIONS

Patients were premedicated 1 hour preoperatively with pethidine 1 mg/kg and atropine 0.01 mg/kg. Following preoxygenation, anesthesia was induced with propofol 2.5 mg/kg and fentanyl 1 mg/kg. Once airway control was established with a facemask, vecuronium 0.1 mg was given and anesthesia established with oxygen (O2) and nitrous oxide mixture and isoflurane 1% to 2%. Gentle direct laryngoscopy was then performed to inspect the pharyngeal structures and the LMA was then inserted in the standard manner by highly experienced LMA users. A fiberoptic scope was passed via a self-sealing mount down the shaft of the LMA to the level of the vocal cords. The vocal cords were then sprayed with local anesthetic and the biopsy taken.

MEASUREMENTS AND MAIN RESULTS

The age and weight range were 29 to 57 years and 65 to 85 kg, respectively. All patients were smokers or recent ex-smokers. LMA insertion was readily achieved in all patients, and an excellent view of the vocal cords was obtained. There were no problems with ventilation or obtaining tissue samples, and O2 saturation remained greater than 95% throughout the perioperative period. Tissue samples were adequate in all patients. Hypertension and other adverse cardiac events did not occur during the procedure, which lasted 10 to 20 minutes. There were no problems during emergence from anesthesia, and all patients were discharged home on the same day.

CONCLUSIONS

The technique has potential advantages over suspension microlaryngoscopy in that it is relatively noninvasive, it allows good airway control with adequate views of the vocal cords, and it facilitates a smooth recovery.

Anaesthesia for laser pharyngoplasty--a comparison of the tracheal tube with the reinforced laryngeal mask airway

A common cause of snoring is palatal flutter which occurs when turbulent air flow causes the flexible soft palate to flutter. Surgical correction involves either removal of the soft palate or a reduction in its flexibility. Laser pharyngoplasty is a new surgical procedure designed to stiffen the soft palate. It presents a unique combination of problems for the anaesthetist. In this paper we describe the evolution of the anaesthetic technique for laser pharyngoplasty and analyse the results of the first 165 cases. Points of particular interest include the use of the reinforced laryngeal mask airway compared with the tracheal tube and late onset pain.

Epidermolysis bullosa. A case report

Epidermolysis bullosa is a group of rare genetic-related skin disorders. It is characterized by bullae and vesicles on the skin and mucosa, that result from friction, trauma, or heat. This article reports a case of Epidermolysis bullosa. With proper diagnosis, the dentist can treat a patient with this type of disorder without causing bullae as a result of treatment.

[Bronchial carcinoma in patients with lymphoproliferative diseases]

Two patients with malignant lymphoma and synchronous bronchogenic carcinoma are presented; the propensity for development of a second primary tumor in patients with lymphoma and leukemia is emphasized. Bronchogenic carcinoma occurs more frequently than expected in these patients.

Procainamide infusion and acute atrial fibrillation

We report the use of intravenous procainamide infusion in the treatment of fifteen patients with acute atrial fibrillation. Procainamide was infused at 50 mg/min to a maximum of 20 mg/kg, with blood pressure and electrocardiographic monitoring. Ten patients responded, with a mean dose of 8.7 (standard deviation 4.3) mg/kg, four of these reverting to sinus rhythm after a low dose of less than 5.0 mg/kg. Hypotension was a common concomitant and was seen in four cases, but required termination of the infusion only in a patient with cardiomyopathy. An increase in ventricular rate or conversion to atrial flutter was not seen. Intravenous infusion of procainamide is a safe and moderately effective method of cardioversion in acute atrial fibrillation.

Antibody-induced degradation of acetylcholine receptor in myasthenia gravis: clinical correlates and pathogenetic significance

Sera of myasthenic patients containing anti-AChR antibodies increase the rate of degradation of mammalian AChR. This phenomenon, antigenic modulation (AMd), was tested on AChR of rat myotubes in serum from 48 myasthenic patients. Sixty-six percent of the sera increased AChR degradation. AMd activity was higher in more severely affected patients, paralleled clinical evolution in individual patients, and was related to AChR-antibody titer. Steroid treatment and thymectomy did not affect AMd activity. Patients who had a thymoma always had greater AMd activity.

Acute lymphoblastic leukemia in an adult patient

A case of acute lymphoblastic leukemia in an adult patient has been presented. Acute lymphoblastic leukemia is a neoplastic process in which the leukocyte precursors have been transformed and no longer respond to the forces that normally regulate their proliferation and maturation. The symptomatology, diagnostic procedures, and treatment modality have been discussed. Unfortunately, although complete remission was obtained for two years, the patient developed recurrent acute lymphoblastic leukemia and subsequently died from a massive, uncontrollable infection.