The application of RNA sequencing for the diagnosis and genomic classification of pediatric acute lymphoblastic leukemia
BLOOD ADVANCES
Authors: Brown, Lauren M.; Lonsdale, Andrew; Zhu, Andrea; Davidson, Nadia M.; Schmidt, Breon; Hawkins, Anthony; Wallach, Elise; Martin, Michelle; Mechinaud, Francoise M.; Khaw, Seong Lin; Bartolo, Ray C.; Ludlow, Louise E. A.; Challis, Jackie; Brooks, Ian; Petrovic, Vida; Venn, Nicola C.; Sutton, Rosemary; Majewski, Ian J.; Oshlack, Alicia; Ekert, Paul G.
Abstract
Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, and implementation of risk-adapted therapy has been instrumental in the dramatic improvements in clinical outcomes. A key to risk-adapted therapies includes the identification of genomic features of individual tumors, including chromosome number (for hyper- and hypodiploidy) and gene fusions, notably ETV6-RUNX1, TCF3-PBX1, and BCR-ABL1 in B-cell ALL (B-ALL). RNA-sequencing (RNA-seq) of large ALL cohorts has expanded the number of recurrent gene fusions recognized as drivers in ALL, and identification of these new entities will contribute to refining ALL risk stratification. We used RNA-seq on 126 ALL patients from our clinical service to test the utility of including RNA-seq in standard-of-care diagnostic pipelines to detect gene rearrangements and IKZF1 deletions. RNA-seq identified 86% of rearrangements detected by standard-of-care diagnostics. KMT2A (MLL) rearrangements, although usually identified, were the most commonly missed by RNA-seq as a result of low expression. RNA-seq identified rearrangements that were not detected by standard-of-care testing in 9 patients. These were found in patients who were not classifiable using standard molecular assessment. We developed an approach to detect the most common IKZF1 deletion from RNA-seq data and validated this using an RQ-PCR assay. We applied an expression classifier to identify Philadelphia chromosome-like B-ALL patients. T-ALL proved a rich source of novel gene fusions, which have clinical implications or provide insights into disease biology. Our experience shows that RNA-seq can be implemented within an individual clinical service to enhance the current molecular diagnostic risk classification of ALL.
Multichannel 16-QAM Single-Sideband Transmission and Kramers-Kronig Detection Using a Single QD-MLL as the Light Source
JOURNAL OF LIGHTWAVE TECHNOLOGY
Authors: Al-Qadi, Mustafa; Laperle, Charles; Charlton, Doug; O'Sullivan, Maurice; Xie, Chongjin; Hui, Rongqing
Abstract
A 12-channel single-sideband transmission of 16QAMsignals at 18GBdis experimentally demonstrated for the first time using a single quantum-dot mode-locked laser (QD-MLL) as the light source for both the modulated carriers and the continuous wave components. The Kramers-Kronig field reconstruction algorithm was used at the direct detection receiver for signal-signal beat interference cancellation. A total net data rate of >800 Gb/s is achieved over 78 km fiber of 1680 ps/nm accumulated chromatic dispersion with BER= 2x10-3, which is lower than the threshold of hard-decision FEC with 7% overhead. Numerical simulations were also performed to assess the impact of noises from the laser source and the receiver front-end on the system performance.