Abstract 133P
Background
The role of determining the diagnostic value of circulating tumor DNA (ctDNA) and natural blood killers (NK) in the diagnosis of precancerous diseases of the colon and colorectal cancer (CRC) ctDNA and NK indicate disorders in the immune system, can be detected in the blood of patients long before clinical signs of cancer appear and allow treatment to begin at an early stage. The aim was to study NK and ctDNA activity data.
Methods
A liquid biopsy was performed to determine ctDNA – 150studies, and a test to determine the activity of NK (NKVue test) – 600. The isolation of ctDNA from plasma was carried out using the QIAamp Circulating Nucleic Acid Kit. Using the digital PCR system in QIAcuity One nanoplanets (Qiagen), KRAS gene mutations were analyzed (c.34G>C, c.35G>T, c.35G>A, c.35G>C, c.34G>T, c.37G>A, c.38G>C, c.34G>A, c.38G>T) and BRAF (V600E) by digital PCR. QIAcuity Nanoplate 26k 24-well nanoplates and dPCR LNA Mutation Assay reagents were used. The average age is 61.0±4.1 years.
Results
The 600 participants were divided into four groups: the control group (67.8%,407/600), progressive adenomas (PA) (21.1%,127/600), inflammatory bowel disease (IBD) (8.9%,53/600) and CRC (2.2%,13/600). The median activity (MA) of NK cells in patients with CRC was the lowest and =127.0pg/ml (mean value (NW) 166.8pg/ml). In patients with IBD, the level of NK cell activity was reduced (MA – 317.8pg/ml, CP – 498.0pg/ml). The MA of NK cells in individuals with PA =282pg/ml (CP – 594.7pg/ml). In the control group, the MA of NK cells was higher than in the other groups -628.8pg/ml with a PH of -871.0pg/ml. The negative optical density (OP) of determining the activity of NK cells = 0.4 and 1.1 in the diagnosis of CRC and PA, when +OP is 2.5 and 1.0. +likelihood ratio >5 indicates a high probability of disease, whereas OP <5 has little significance. KRAS and BRAF mutations were determined in the ctDNA group. A KRAS mutation was detected in plasma samples from 120 patients, one each in codons 13 and 61, and in 30 patients in codon 12. The V600E BRAF mutation was found in 10 patients.
Conclusions
A study the combination of ctDNA and NK activity can be a useful tool in the early diagnosis and monitoring of PA and CRC.
Legal entity responsible for the study
I. Tirkpenova.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.