Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Jun 20:10:1182093.
doi: 10.3389/fvets.2023.1182093. eCollection 2023.

Clinical utility of liquid biopsy in canine oral malignant melanoma using cell-free DNA

Michihito Tagawa  1   2 , Minori Aoki  1
Affiliations

Clinical utility of liquid biopsy in canine oral malignant melanoma using cell-free DNA

Michihito Tagawa et al. Front Vet Sci. .

Abstract

Introduction: Cell-free DNA (cfDNA), an extracellular free DNA released into the bloodstream by cells, is a potentially useful noninvasive marker to detect human malignancies and monitor response to treatment. In the present study, we evaluated the utility of circulating cfDNA in canine patients with oral malignant melanoma (OMM) in assessing therapeutic response and clinical outcomes.

Methods: Plasma samples were collected from 12 dogs with OMM and 9 healthy controls. cfDNA concentration was quantified by real-time PCR resulting in short (99bp) and long (218bp) fragments of long interspersed nuclear element-1 (LINE-1), and the DNA integrity index (DII) was then calculated (218/99). A follow-up study was conducted on 6 dogs with OMM, and the plasma cfDNA and DII were quantified throughout disease progression.

Results: Although cfDNA levels obtained from dogs with OMM were not significantly different compared to those obtained from healthy controls, the DII was significantly lower in dogs with OMM than in healthy controls. The DII tended to decrease as the disease stage progressed. Moreover, changes in cfDNA concentration and DII along the clinical course were observed when major changes, such as metastasis or apparent tumor progression, were observed.

Discussion: The results of our study suggest that measurements of serum cfDNA and DII using LINE-1 might be valuable new biomarkers for monitoring OMM progression in dogs. This preliminary study demonstrated the potential clinical utility of monitoring plasma cfDNA in canine patients with OMM.

Keywords: DNA integrity index; LINE-1; cell-free DNA; dog; liquid biopsy; melanoma.

PubMed Disclaimer

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
(A) Cell-free DNA (cfDNA) concentration of LINE-1 (99 bp) in plasma of dogs with oral malignant melanoma (OMM) and healthy controls (CON). (B) cfDNA concentration of LINE-1 (99 bp) in plasma of dogs with OMM grouped by tumor stage. (C) DNA integrity index (DII) in plasma of dogs with OMM and healthy controls. (D) DII in plasma of dogs with OMM grouped by tumor stage. All blood samplings were performed before any tumor-specific treatment. Each box plot indicates the 25th and 75th percentiles. The horizontal line inside the box indicates the median value, and the whiskers indicate the extreme measured values. The p-values and R-squared values are shown.
Figure 2
Figure 2
Kaplan–Meier curves of survival time in dogs with oral malignant melanoma according to cut-off values based on (A) cell-free DNA (cfDNA) concentrations and (B) DNA integrity index (DII). Cut-off and p-values are shown. +: Censored case.
Figure 3
Figure 3
Monitoring of cell-free DNA (cfDNA) concentrations (red lines) and DNA integrity index (DII; blue lines) in plasma from dogs with oral malignant melanoma according to treatment response. In each case, the patient was administered orthovoltage radiation treatment (gray bar); all cases were treated with non-steroidal anti-inflammatory drugs except for case 6 after radiation therapy. CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease; PM, pulmonary metastasis; LM, lymph node metastasis.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. MacEwen EG, Patnaik AK, Harvey HJ, Hayes AA, Matus R. Canine oral melanoma: comparison of surgery versus surgery plus Corynebacterium parvum. Cancer Invest. (1986) 4:397–402. 10.3109/07357908609017520 - DOI - PubMed
    1. Tuohy JL, Selmic LE, Worley DR, Ehrhart NP, Withrow SJ. Outcome following curative-intent surgery for oral melanoma in dogs: 70 cases (1998–2011). J Am Vet Med Assoc. (2014) 245:1266–73. 10.2460/javma.245.11.1266 - DOI - PubMed
    1. Treggiari E, Grant JP, North SM, A. retrospective review of outcome and survival following surgery and adjuvant xenogeneic DNA vaccination in 32 dogs with oral malignant melanoma. J Vet Med Sci. (2016) 78:845–50. 10.1292/jvms.15-0510 - DOI - PMC - PubMed
    1. Pazzi P, Steenkamp G, Rixon AJ. Treatment of canine oral melanomas: a critical review of the literature. Vet Sci. (2022) 9:196. 10.3390/vetsci9050196 - DOI - PMC - PubMed
    1. Kawabe M, Mori T, Ito Y, Murakami M, Sakai H, Yanai T, et al. . Outcomes of dogs undergoing radiotherapy for treatment of oral malignant melanoma: 111 cases (2006–2012). J Am Vet Med Assoc. (2015) 247:1146–53. 10.2460/javma.247.10.1146 - DOI - PubMed

Grants and funding

This work was supported by the JSPS KAKENHI (grant number JP21K05952).

LinkOut - more resources