Potential of modern circulating cell-free DNA diagnostic tools for detection of specific tumour cells in clinical practice

PN, Gimenes N, Reis MX, Matsas S, Ferreira CG. Next-generation sequencing impact on cancer care: applications, challenges, and future directions

Fundamentally precision oncology illustrates the path in which molecular profiling of tumors can illuminate their biological behavior, diversity, and likely outcomes by identifying distinct genetic mutations, protein levels, and other biomarkers that underpin cancer progression. Next-generation sequencing became an indispensable diagnostic tool for diagnosis and treatment guidance in current clinical practice. Nowadays, tissue analysis benefits from further support through methods like comprehensive genomic profiling and liquid biopsies. However, precision medicine in the field of oncology presents specific hurdles, such as the cost-benefit balance and widespread accessibility, particularly in countries with low- and middle-income. A key issue is how to effectively extend next-generation sequencing to all cancer patients, thus empowering treatment decision-making. Concerns also extend to the quality and preservation of tissue samples, as well as the evaluation of health technologies. Moreover, as technology advances, novel next-generation sequencing assessments are being developed, including the study of Fragmentomics. Therefore, our objective was to delineate the primary uses of next-generation sequencing, discussing its' applications, limitations, and prospective paths forward in Oncology.

[Clinical Application Examples of a Next-Generation Sequencing based Multi-Genepanel Analysis]

This review provides an overview of clinically useful applications of a next-generation sequencing (NGS)-based multi-gene panel testing strategy in the areas of oncology, hereditary tumor syndromes, and hematology. In the case of solid tumors (e.g. lung carcinoma, colon-rectal carcinoma), the detection of somatic mutations contributes not only to a better diagnostic but also therapeutic stratification of those affected. The increasing genetic complexity of hereditary tumor syndromes (e.g. breast and ovarian carcinoma, lynch syndrome/polyposis) requires a multi-gene panel analysis of germline mutations in affected families. Another useful indication for a multi-gene panel diagnostics and prognosis assessment are acute and chronic myeloid diseases. The criteria of the WHO-classification and the European LeukemiaNet-prognosis system for acute myeloid leukemia can only be met by a multi-gene panel test strategy.

Ultra-rapid somatic variant detection via real-time targeted amplicon sequencing

Molecular markers are essential for cancer diagnosis, clinical trial enrollment, and some surgical decision making, motivating ultra-rapid, intraoperative variant detection. Sequencing-based detection is considered the gold standard approach, but typically takes hours to perform due to time-consuming DNA extraction, targeted amplification, and library preparation times. In this work, we present a proof-of-principle approach for sub-1 hour targeted variant detection using real-time DNA sequencers. By modifying existing protocols, optimizing for diagnostic time-to-result, we demonstrate confirmation of a hot-spot mutation from tumor tissue in ~52 minutes. To further reduce time, we explore rapid, targeted Loop-mediated Isothermal Amplification (LAMP) and design a bioinformatics tool-LAMPrey-to process sequenced LAMP product. LAMPrey's concatemer aware alignment algorithm is designed to maximize recovery of diagnostically relevant information leading to a more rapid detection versus standard read alignment approaches. Using LAMPrey, we demonstrate confirmation of a hot-spot mutation (250x support) from tumor tissue in less than 30 minutes.

Harnessing Liquid Biopsies to Guide Immune Checkpoint Inhibitor Therapy

Immunotherapy (IO), involving the use of immune checkpoint inhibition, achieves improved response-rates and significant disease-free survival for some cancer patients. Despite these beneficial effects, there is poor predictability of response and substantial rates of innate or acquired resistance, resulting in heterogeneous responses among patients. In addition, patients can develop life-threatening adverse events, and while these generally occur in patients that also show a tumor response, these outcomes are not always congruent. Therefore, predicting a response to IO is of paramount importance. Traditionally, tumor tissue analysis has been used for this purpose. However, minimally invasive liquid biopsies that monitor changes in blood or other bodily fluid markers are emerging as a promising cost-effective alternative. Traditional biomarkers have limitations mainly due to difficulty in repeatedly obtaining tumor tissue confounded also by the spatial and temporal heterogeneity of tumours. Liquid biopsy has the potential to circumvent tumor heterogeneity and to help identifying patients who may respond to IO, to monitor the treatment dynamically, as well as to unravel the mechanisms of relapse. We present here a review of the current status of molecular markers for the prediction and monitoring of IO response, focusing on the detection of these markers in liquid biopsies. With the emerging improvements in the field of liquid biopsy, this approach has the capacity to identify IO-eligible patients and provide clinically relevant information to assist with their ongoing disease management.

Molecular testing for acute myeloid leukemia

In the era of personalized medicine, information on molecular change at the gene level is important for patient care. Such information has been used for disease classification, diagnosis, prognosis, risk stratification, and treatment, which is especially important in cancer patient care. Many molecular tests exist and can be used to detect the molecular changes at gene level. These tests include, but are not limited to, karyotyping, endpoint polymerase chain reaction (PCR), real-time PCR, Sanger sequencing, pyrosequencing, next-generation sequencing, and so forth. How to use the right tests for the right patients at the right time is essential for optimal patient outcome. This review puts together some information on molecular testing for acute myeloid leukemia.