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The Genetics of Spontaneous Abortions
Published in Howard J.A. Carp, Recurrent Pregnancy Loss, 2020
Noninvasive prenatal testing screening (NIPS) detecting cell free DNA in the maternal circulation is widely applied in ongoing pregnancies for detecting fetuses with trisomies 13, 18, and 21. This method can be envisioned as equally applicable in the management of miscarriages. Thus, a maternal blood sample is capable of providing information concerning whether a miscarriage was aneuploid or euploid. This molecular approach uses massive parallel sequencing analysis of the fragments of DNA (circulating free DNA [cfDNA]) present in blood of all individuals—pregnant or not. During pregnancy, maternal blood contains cell free DNA from multiple maternal organs and fetal tissue mostly generated from the placenta. NIPS has proved capable of 99.9% detection for trisomy 21, 98% for trisomy 18, and at least 80% for trisomy 13 [7,8]. NIPS, usually performed at 10–12 weeks’ gestation, can be used to screen for sex chromosome abnormalities in addition to the common trisomies (13, 18, and 21) both in cohorts of maternal age ≥35 years and in cohorts <35 years.
Colorectal Cancer
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Most of the colon and the anterior wall of the rectum are covered by serosa. Ulceration of this by tumor constitutes a breach of the peritoneum and a route for the dissemination of malignant cells into the abdominal cavity. Colonic tumors with microscopic serosal surface ulceration by tumor resulted in peritoneal recurrence in 50% of cases.60 Although typically, metastases involve nodes sequentially corresponding to the anatomical sequence of drainage, in advanced carcinomas, node blockage “upstream” by tumor can result in retrograde lymph-node spread. The 5-year survival for Dukes’ C (Stage III) with one node positive is 63.6%, but falls to 2.1% when more than 10 nodes are involved. At least 12 lymph nodes are needed for accurate staging.61 The routine analysis of hematoxylin and eosin sections of nodes is as sensitive as ancillary techniques in identifying tumor involvement compared with using additional CEA and epithelial membrane antigen (EMA) immunohistochemical techniques (Table 15.2).62 Studies that have re-staged patients after additional immunohistochemical examination for micro-metastases have failed to show any difference in predicting 5-year survival.63 Furthermore, tumor may disseminate via the portal venous system to the liver and in low rectal carcinomas, via the inferior hemorrhoidal veins directly to the lungs. Prognosis is adversely affected when thicker-walled-caliber extramural veins are involved.64 Similarly, newer technologies in routine detection of circulating tumor cells (CTCs) or residual postoperative total circulating free DNA thought to be shed from residual cancer cells (ct- or cf-DNA) have suggested additional prognostic value, but are rarely used in routine clinical practice to guide clinical decision making.
Utilizing circulating tumour DNA as a prognostic predictor of gastric cancer: a meta-analysis
Published in Biomarkers, 2023
Liang Min, Jinghua Chen, Meihong Yu, Ke Yang, Deliang Liu
Since the first study revealed the higher levels of circulating free DNA (cfDNA), fragments of extracellular DNA, in the blood of patients with a broad spectrum of cancers in 1977 (Leon et al.1977), accumulating evidence has depicted the potential of cfDNA to be a widely used diagnostic and prognostic biomarker in various cancer (Yan et al. 2021a, 2021b). In general, cfDNA is released from dying cells into biological fluid and mainly derived from haematopoietic system in healthy population (Heitzer et al.2020). Similarly, apoptotic or necrotic cancer cell released DNA called circulating tumour DNA (ctDNA), which may carry specific tumour information including single-nucleotide variants (SNVs) (Kim et al.2020), copy number aberration (CNV) (Peng et al.2019), DNA methylation (Xu et al.2017) and microsatellite instability (MSI) (Cai et al.2020), into body fluid in cancer patients. With the development of DNA assay and sequencing techniques, detection and analysis of ctDNA can contribute to a better diagnosis, evaluation, and monitoring of the cancers (Pessoa et al.2020).
Identifying and clinically validating biomarkers for immunotherapy in colorectal cancer
Published in Expert Review of Molecular Diagnostics, 2023
Yung-Sung Yeh, Hsiang-Lin Tsai, Po-Jung Chen, Yen-Cheng Chen, Wei-Chih Su, Tsung-Kun Chang, Ching-Wen Huang, Jaw-Yuan Wang
While most circulating free DNA originates from the hematopoietic system in a healthy person [71], apoptotic or necrotic cancer cells release DNA called circulating tumor DNA (ctDNA) into the biological fluid in cancer as a small proportion of cfDNA in cancer patients [72]. ctDNA has emerged as a promising biomarker for many kinds of tumors. However, whether ctDNA could be an accurate diagnostic biomarker in CRC remains to be clarified. Accumulating evidence indicated that ctDNA is a promising biomarker in CRC screening and diagnosis, there are some concerns about the application of ctDNA in diagnosis of CRC due to the tumor heterogeneous, unstandardized protocol and concentration threshold. However, whether ctDNA could be an accurate diagnostic biomarker in CRC remains to be further elucidated [73].
dPCR application in liquid biopsies: divide and conquer
Published in Expert Review of Molecular Diagnostics, 2021
Andrea Moreno-Manuel, Silvia Calabuig-Fariñas, Antonia Obrador-Hevia, Ana Blasco, Amaya Fernández-Díaz, Rafael Sirera, Carlos Camps, Eloisa Jantus-Lewintre
Blood samples are the most widely used type of LB given that blood contains several types of tumor-derived material that can be used as a source for biomarker testing [4,5]. This includes circulating tumor cells (CTCs), circulating tumor DNA and RNA (ctDNA, ctRNA and, miRNA), as well as circulating proteins, metabolites, and exosomes; being ctDNA the most commonly analyzed matrix due to the advances in technique standardization. Nevertheless, circulating free DNA (cfDNA) contains DNA from both cancer and normal cells, meaning that highly sensitive techniques are required for the accurate analysis of the molecular alterations in tumor-derived DNA [6–8]. Therefore, the paradigm of cancer diagnosis and treatment is continuously under revision because of the development of new and more sensitive and accurate diagnostic techniques. ln this evolving scenario, LB has demonstrated its clinical utility in several studies and clinical trials as a reliable source of material for use in tumor biomarker analyses [9–11].