The evidence base for circulating tumour DNA blood-based biomarkers for the early detection of cancer: a systematic mapping review

Background: The presence of circulating cell-free DNA from tumours in blood (ctDNA) is of major importance to those interested in early cancer detection, as well as to those wishing to monitor tumour progression or diagnose the presence of activating mutations to guide treatment. In 2014, the UK Early Cancer Detection Consortium undertook a systematic mapping review of the literature to identify blood-based biomarkers with potential for the development of a non-invasive blood test for cancer screening, and which identified this as a major area of interest. This review builds on the mapping review to expand the ctDNA dataset to examine the best options for the detection of multiple cancer types. Methods: The original mapping review was based on comprehensive searches of the electronic databases Medline, Embase, CINAHL, the Cochrane library, and Biosis to obtain relevant literature on blood-based biomarkers for cancer detection in humans (PROSPERO no. CRD42014010827). The abstracts for each paper were reviewed to determine whether validation data were reported, and then examined in full. Publications concentrating on monitoring of disease burden or mutations were excluded. Results: The search identified 94 ctDNA studies meeting the criteria for review. All but 5 studies examined one cancer type, with breast, colorectal and lung cancers representing 60% of studies. The size and design of the studies varied widely. Controls were included in 77% of publications. The largest study included 640 patients, but the median study size was 65 cases and 35 controls, and the bulk of studies (71%) included less than 100 patients. Studies either estimated cfDNA levels non-specifically or tested for cancer-specific mutations or methylation changes (the majority using PCR-based methods). Conclusion: We have systematically reviewed ctDNA blood biomarkers for the early detection of cancer. Pre-analytical, analytical, and post-analytical considerations were identified which need to be addressed before such biomarkers enter clinical practice. The value of small studies with no comparison between methods, or even the inclusion of controls is highly questionable, and larger validation studies will be required before such methods can be considered for early cancer detection

Neoadjuvant therapy affects tumor growth markers in early stage non-small-cell lung cancer

Abstract Introduction While adjuvant therapy of early-stage non-small-cell lung cancer (NSCLC) is widely accepted, literature data concerning neoadjuvant treatment provide contradictory results with both improved and unaffected survival rates. Also, data concerning potential effects of neo-adjuvant therapy on cellular level are scarce. Objective The aim of present study was to analyze the effect of chemotherapy followed by surgical resection on several key biological markers of tumor growth (TGF-β, VEGF), apoptosis (sAPO-1/Fas/CD95) and invasiveness (TIMP-1) assessed in the sera of NSCLC early-stage patients (IB-IIIA). Materials and methods Measurements were performed by ELISA method in blood serum from 24 NSCLC patients (I-IIIA) collected prior therapy, one day before surgery and 3 days after. Results TGF-β serum concentrations were significantly lower after both chemotherapy (P Conclusion Neoadjuvant treatment of early-stage NSCLC affects mostly mechanisms responsible for tumor growth and vascularization. Its effect on cancer cells apoptotic activity needs further evaluation.</p