Prevalence of T790M mutation among TKI-therapy resistant Lebanese lung cancer patients based on liquid biopsy analysis: a first report from a major tertiary care center.

Lung adenocarcinoma patients have variable prognosis due to many factors. Detection of epidermal growth factor receptor (EGFR) activating mutations is one of the factors that implies the need for initiating a first-line EGFR tyrosine kinase inhibitor (TKI) treatment. However, T790M resistance mutation emergence during treatment accounts for most EGFR-TKI drug resistance. The traditional sample taken for T790M mutation analysis is tissue biopsy, but its numerous disadvantages have introduced liquid biopsy as a preferred method for testing. We studied the prevalence of T790M mutation among pulmonary adenocarcinoma patients in Lebanese patients based on liquid biopsy testing the circulating tumor DNA (ctDNA). We have reviewed the laboratory charts of 52 patients who developed resistance on treatment and referred to AUBMC for EGFR T790M Liquid Biopsy to analyze the mutational analysis results for EGFR T790M. In total, 82.6% of the tested lung cancer patients were positive for a specific EGFR mutation. Among these patients, a total 26.9% were positive for T790M, which is comparable to the international prevalence of this mutation. However, for those cases who developed resistance with circulating DNA showing an EGFR mutation, 50% were positive for T790M that is also comparable to the international literature. This is the first report from Lebanon to discuss the prevalence of T790M mutation using liquid biopsy among Lebanese population. An important landmark molecular epidemiology study that will be a reference to all oncologists in Lebanon and the region in assessing the potential for targeted therapy options in the country. In addition, the data will be of an asset to the building international literature related to this disease.

Comparison of the Artus RotorGene and COBAS Ampliprep/COBAS TaqMan Platforms for the Detection of Cytomegalovirus: Experience of a Tertiary Care Center.

INTRODUCTION: Cytomegalovirus (CMV) is a member of the Herpesviruses family. CMV infection rarely causes serious disease in otherwise healthy individuals, however, infection/reactivation among immunocompromised patients, including those undergoing hematopoietic stem cell transplantation (HSCT), can be critical and is associated with high rates of morbidity and mortality. The detection of CMV in blood using real-time polymerase chain reaction (qPCR) methods is the most sensitive and specific technique providing for a well-determined preemptive treatment cutoff. AIM: This study compares the performance of two new CMV qPCR platforms, COBAS(®) Ampliprep/COBAS(®) TaqMan(®) (Roche Molecular Diagnostics) and Artus RotorGene (QIAGEN). METHODS: A total of 99 patients referred for CMV testing at AUBMC were tested using the Artus CMV RG PCR kit and the COBAS AmpliPrep/COBAS TaqMan CMV kit as per the manufacturers' recommendations. RESULTS: The difference between the two methods was within the allowable error for 97 out of 99 specimens (98%), with a correlation coefficient r = 0.80. CONCLUSION: The Artus CMV RG PCR Kit and the COBAS AmpliPrep/COBAS TaqMan CMV kit are both acceptable assays that can be used for the sensitive detection and quantitation of CMV mainly in peripheral blood specimens.

Invivoscribe BIOMED-2 primer mixes in B-cell immunoglobulin gene rearrangement studies: experience of a molecular diagnostics laboratory in a major tertiary care center.

AIMS: To determine the frequency of positive reactions obtained using the Invivoscribe BIOMED-2 kit for B-cell gene rearrangement studies in leukemias and lymphomas. MATERIALS AND METHODS: We reviewed the gel patterns for 192 samples tested, using the above-mentioned kit and matched the positive signal with the corresponding mix available in the assay kit. RESULTS: 92.2% had immunoglobulin heavy-chain clonality, of which 74% were detected by the IgH VH-FR1+JH primer set, 75.5% by IgH VH-FR2+JH primer set, 65.1% by IgH VH-FR3+JH primer set, 26% by IgH DH+JH primer set, and 2.1% by IgH DH7+JH primer set. In addition, 55.7% had clonality in the kappa light chain, where 33.3% were positive by the IgK Vκ +Jκ primer set and 39.6% by IgK Vκ and INTR+Kde primer sets. Clonality in the lambda light chain of immunoglobulins was detected in 17.7% of specimens tested using the IgL Vλ +Jλ primer set. CONCLUSION: All primer mixes provided by the assay were positive. Thus, the Invivoscribe BIOMED-2 B-cell gene rearrangement kit is very reliable in adequately covering all targets represented by the master mixes. This assay is an integral part of the differential diagnosis of clonal populations of cells. Our report is the first in the literature that describes the full range of coverage of the BIOMED-2 primer mixes provided in this assay.