TY  - JOUR
AU  - Prosenc-Zmrzljak, Ursula
AU  - Kosir, Rok
AU  - Krivokapić, Zoran
AU  - Radojković, Dragica
AU  - Nikolić, Aleksandra
PY  - 2021
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1494
AB  - Liquid biopsy and cell-free DNA (cfDNA) show great promise in cancer diagnostics. In this study, we designed a custom droplet digital PCR (ddPCR) assay for the quantification and quality control of cfDNA isolated from serum. The assay was validated on a group of locally advanced colorectal cancer (CRC) patients and two control groups-patients with hemorrhoids and healthy individuals. The assay shows a high correlation with Qubit measurement (r = 0.976) but offers a higher dynamic range. Mean concentrations of cfDNA were 12.36 ng/mu L, 5.17 ng/mu L, and 0.29 ng/mu L for CRC, hemorrhoid patients, and healthy controls, respectively. The quality of cfDNA was assessed with the measurement of B-cell DNA contamination. On a subset of CRC patients, we compared the mutation status on KRAS (G12A, G12D, G12V, G13D) and BRAF (V600E) genes in the primary tumor and cfDNA isolated from the serum. A total of 70.6% of primary tumor samples were mutated, and the mean fractional abundance of mutations was 9.50%. The matching serum samples were mutated in 38% cases with an average fractional abundance of 0.23%. We conclude that any decisions based solely on the amount of cfDNA present in patient serum must be interpreted carefully and in the context of co-morbidities. This study explores the potential of ddPCR somatic mutations detection from liquid biopsy as a supplement to tissue biopsy in targeted personalized CRC patient management.
PB  - MDPI, Basel
T2  - Genes
T1  - Detection of Somatic Mutations with ddPCR from Liquid Biopsy of Colorectal Cancer Patients
IS  - 2
VL  - 12
DO  - 10.3390/genes12020289
ER  - 

@article{
author = "Prosenc-Zmrzljak, Ursula and Kosir, Rok and Krivokapić, Zoran and Radojković, Dragica and Nikolić, Aleksandra",
year = "2021",
abstract = "Liquid biopsy and cell-free DNA (cfDNA) show great promise in cancer diagnostics. In this study, we designed a custom droplet digital PCR (ddPCR) assay for the quantification and quality control of cfDNA isolated from serum. The assay was validated on a group of locally advanced colorectal cancer (CRC) patients and two control groups-patients with hemorrhoids and healthy individuals. The assay shows a high correlation with Qubit measurement (r = 0.976) but offers a higher dynamic range. Mean concentrations of cfDNA were 12.36 ng/mu L, 5.17 ng/mu L, and 0.29 ng/mu L for CRC, hemorrhoid patients, and healthy controls, respectively. The quality of cfDNA was assessed with the measurement of B-cell DNA contamination. On a subset of CRC patients, we compared the mutation status on KRAS (G12A, G12D, G12V, G13D) and BRAF (V600E) genes in the primary tumor and cfDNA isolated from the serum. A total of 70.6% of primary tumor samples were mutated, and the mean fractional abundance of mutations was 9.50%. The matching serum samples were mutated in 38% cases with an average fractional abundance of 0.23%. We conclude that any decisions based solely on the amount of cfDNA present in patient serum must be interpreted carefully and in the context of co-morbidities. This study explores the potential of ddPCR somatic mutations detection from liquid biopsy as a supplement to tissue biopsy in targeted personalized CRC patient management.",
publisher = "MDPI, Basel",
journal = "Genes",
title = "Detection of Somatic Mutations with ddPCR from Liquid Biopsy of Colorectal Cancer Patients",
number = "2",
volume = "12",
doi = "10.3390/genes12020289"
}

Prosenc-Zmrzljak, U., Kosir, R., Krivokapić, Z., Radojković, D.,& Nikolić, A.. (2021). Detection of Somatic Mutations with ddPCR from Liquid Biopsy of Colorectal Cancer Patients. in Genes
MDPI, Basel., 12(2).
https://doi.org/10.3390/genes12020289

Prosenc-Zmrzljak U, Kosir R, Krivokapić Z, Radojković D, Nikolić A. Detection of Somatic Mutations with ddPCR from Liquid Biopsy of Colorectal Cancer Patients. in Genes. 2021;12(2).
doi:10.3390/genes12020289 .

Prosenc-Zmrzljak, Ursula, Kosir, Rok, Krivokapić, Zoran, Radojković, Dragica, Nikolić, Aleksandra, "Detection of Somatic Mutations with ddPCR from Liquid Biopsy of Colorectal Cancer Patients" in Genes, 12, no. 2 (2021),
https://doi.org/10.3390/genes12020289 . .

TY  - JOUR
AU  - Petrović-Sunderić, Jelena
AU  - Dragičević, Sandra
AU  - Krnjajić, Mina
AU  - Ristanović, Momcilo
AU  - Nikolić, Aleksandra
AU  - Krivokapić, Zoran
PY  - 2018
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1115
AB  - Purpose: The RAD51 gene plays an important role in homologous strand exchange in DNA repair. Two common single nucleotide polymorphisms in this gene, 135G  gt  C and 172G  gt  T, were associated with altered gene transcription. While 135G  gt  C was already linked to breast and colorectal cancers in certain populations, 172G  gt  T is far less investigated, although sporadic studies showed it could be a prognostic factor for some cancer lesions. The purpose of this study was to investigate RAD51 172G  gt  T polymorphism in Serbian population, its association with colorectal carcinoma, as well as correlation with disease characteristics and response to neoadjuvant chemoradiotherapy. Methods: The 172G  gt  T polymorphism was evaluated by PCR-RFLP method in blood samples of 209 colorectal cancer patients and 43 healthy subjects who served as controls. The distribution of genotypes was also analyzed in respect to several tumor characteristics in cases where histopathological data were available. Results: A significant association between the RAD51 172G  gt  T polymoprhism and desmoplastic reaction of colorectal cancer was demonstrated. The 172G allele was found to be significantly more frequent in patients with more intensive desmoplastic response of the tumor tissue. Conclusions: The results of our study suggest that the 172T allele of RAD51 may be a favorable prognostic factor in Serbian patients with colorectal cancer, although larger prospective studies are required to confirm this finding.
PB  - Balkan Union of Oncology (B.U.ON.)
T2  - Journal of Buon
T1  - Polymorphism RAD51 172G > T in Serbian patients with colorectal cancer
EP  - 940
IS  - 4
SP  - 936
VL  - 23
UR  - https://hdl.handle.net/21.15107/rcub_imagine_1115
ER  - 

@article{
author = "Petrović-Sunderić, Jelena and Dragičević, Sandra and Krnjajić, Mina and Ristanović, Momcilo and Nikolić, Aleksandra and Krivokapić, Zoran",
year = "2018",
abstract = "Purpose: The RAD51 gene plays an important role in homologous strand exchange in DNA repair. Two common single nucleotide polymorphisms in this gene, 135G  gt  C and 172G  gt  T, were associated with altered gene transcription. While 135G  gt  C was already linked to breast and colorectal cancers in certain populations, 172G  gt  T is far less investigated, although sporadic studies showed it could be a prognostic factor for some cancer lesions. The purpose of this study was to investigate RAD51 172G  gt  T polymorphism in Serbian population, its association with colorectal carcinoma, as well as correlation with disease characteristics and response to neoadjuvant chemoradiotherapy. Methods: The 172G  gt  T polymorphism was evaluated by PCR-RFLP method in blood samples of 209 colorectal cancer patients and 43 healthy subjects who served as controls. The distribution of genotypes was also analyzed in respect to several tumor characteristics in cases where histopathological data were available. Results: A significant association between the RAD51 172G  gt  T polymoprhism and desmoplastic reaction of colorectal cancer was demonstrated. The 172G allele was found to be significantly more frequent in patients with more intensive desmoplastic response of the tumor tissue. Conclusions: The results of our study suggest that the 172T allele of RAD51 may be a favorable prognostic factor in Serbian patients with colorectal cancer, although larger prospective studies are required to confirm this finding.",
publisher = "Balkan Union of Oncology (B.U.ON.)",
journal = "Journal of Buon",
title = "Polymorphism RAD51 172G > T in Serbian patients with colorectal cancer",
pages = "940-936",
number = "4",
volume = "23",
url = "https://hdl.handle.net/21.15107/rcub_imagine_1115"
}

Petrović-Sunderić, J., Dragičević, S., Krnjajić, M., Ristanović, M., Nikolić, A.,& Krivokapić, Z.. (2018). Polymorphism RAD51 172G > T in Serbian patients with colorectal cancer. in Journal of Buon
Balkan Union of Oncology (B.U.ON.)., 23(4), 936-940.
https://hdl.handle.net/21.15107/rcub_imagine_1115

Petrović-Sunderić J, Dragičević S, Krnjajić M, Ristanović M, Nikolić A, Krivokapić Z. Polymorphism RAD51 172G > T in Serbian patients with colorectal cancer. in Journal of Buon. 2018;23(4):936-940.
https://hdl.handle.net/21.15107/rcub_imagine_1115 .

Petrović-Sunderić, Jelena, Dragičević, Sandra, Krnjajić, Mina, Ristanović, Momcilo, Nikolić, Aleksandra, Krivokapić, Zoran, "Polymorphism RAD51 172G > T in Serbian patients with colorectal cancer" in Journal of Buon, 23, no. 4 (2018):936-940,
https://hdl.handle.net/21.15107/rcub_imagine_1115 .

TY  - JOUR
AU  - Nikolić, Aleksandra
AU  - Vlajnić, Marina
AU  - Ristanović, Momcilo
AU  - Petrović, Jelena
AU  - Dimitrijević, Ivan
AU  - Krivokapić, Zoran
AU  - Radojković, Dragica
PY  - 2017
UR  - https://imagine.imgge.bg.ac.rs/handle/123456789/1036
AB  - Purpose: To analyze if cell free (cf)DNA levels and the presence of KRAS and BRAF mutations in serum could be used as diagnostic biomarkers in patients with primary colorectal cancer (CRC). Methods: This study included 92 individuals who were operated due to primary CRC (N=52;study group) and to hemorrhoids (N=40;control group). Serum cfDNA levels were measured with real-time PCR (RT-PCR) using PicoGreen dsDNA quantitation reagent. Colorectal tissue and related blood and serum samples taken at the time of surgery were subjected to DNA extraction and analysis of KRAS and BRAF mutations based on multiplex SNaPshot assay and DNA sequencing. Results: The average cfDNA concentration was lower in patients of the study group (20 +/- 7 ng/mu L) in comparison to controls (34 +/- 9 ng/mu L) and this difference was statistically significant (p lt 0.001). The SNaPshot analysis detected KRAS c35 mutations in colorectal tumor tissue in 14 cases, but the presence of the mutation was not confirmed in cfD-NA extracted from blood samples of these patients. Conclusions: The level of serum cfDNA in CRC is decreased in comparison to patients with hemorrhoids, which questions the usefulness of cfDNA as cancer biomarker. Also, cfDNA does not appear to be suitable as a source for mutation detection in this disease.
PB  - Balkan Union of Oncology (B.U.ON.)
T2  - Journal of Buon
T1  - Cell-free DNA as biomarker and source for mutation detection in primary colorectal cancer
EP  - 183
IS  - 1
SP  - 178
VL  - 22
UR  - https://hdl.handle.net/21.15107/rcub_imagine_1036
ER  - 

@article{
author = "Nikolić, Aleksandra and Vlajnić, Marina and Ristanović, Momcilo and Petrović, Jelena and Dimitrijević, Ivan and Krivokapić, Zoran and Radojković, Dragica",
year = "2017",
abstract = "Purpose: To analyze if cell free (cf)DNA levels and the presence of KRAS and BRAF mutations in serum could be used as diagnostic biomarkers in patients with primary colorectal cancer (CRC). Methods: This study included 92 individuals who were operated due to primary CRC (N=52;study group) and to hemorrhoids (N=40;control group). Serum cfDNA levels were measured with real-time PCR (RT-PCR) using PicoGreen dsDNA quantitation reagent. Colorectal tissue and related blood and serum samples taken at the time of surgery were subjected to DNA extraction and analysis of KRAS and BRAF mutations based on multiplex SNaPshot assay and DNA sequencing. Results: The average cfDNA concentration was lower in patients of the study group (20 +/- 7 ng/mu L) in comparison to controls (34 +/- 9 ng/mu L) and this difference was statistically significant (p lt 0.001). The SNaPshot analysis detected KRAS c35 mutations in colorectal tumor tissue in 14 cases, but the presence of the mutation was not confirmed in cfD-NA extracted from blood samples of these patients. Conclusions: The level of serum cfDNA in CRC is decreased in comparison to patients with hemorrhoids, which questions the usefulness of cfDNA as cancer biomarker. Also, cfDNA does not appear to be suitable as a source for mutation detection in this disease.",
publisher = "Balkan Union of Oncology (B.U.ON.)",
journal = "Journal of Buon",
title = "Cell-free DNA as biomarker and source for mutation detection in primary colorectal cancer",
pages = "183-178",
number = "1",
volume = "22",
url = "https://hdl.handle.net/21.15107/rcub_imagine_1036"
}

Nikolić, A., Vlajnić, M., Ristanović, M., Petrović, J., Dimitrijević, I., Krivokapić, Z.,& Radojković, D.. (2017). Cell-free DNA as biomarker and source for mutation detection in primary colorectal cancer. in Journal of Buon
Balkan Union of Oncology (B.U.ON.)., 22(1), 178-183.
https://hdl.handle.net/21.15107/rcub_imagine_1036

Nikolić A, Vlajnić M, Ristanović M, Petrović J, Dimitrijević I, Krivokapić Z, Radojković D. Cell-free DNA as biomarker and source for mutation detection in primary colorectal cancer. in Journal of Buon. 2017;22(1):178-183.
https://hdl.handle.net/21.15107/rcub_imagine_1036 .

Nikolić, Aleksandra, Vlajnić, Marina, Ristanović, Momcilo, Petrović, Jelena, Dimitrijević, Ivan, Krivokapić, Zoran, Radojković, Dragica, "Cell-free DNA as biomarker and source for mutation detection in primary colorectal cancer" in Journal of Buon, 22, no. 1 (2017):178-183,
https://hdl.handle.net/21.15107/rcub_imagine_1036 .