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Non-invasive tape sampling of tryptophan and kynurenine in relation to phenylalanine and tyrosine from melanoma and adjacent non-lesional skin : A pilot study

Jankovskaja, Skaidre LU ; Spégel, Peter LU ; Nielsen, Kari LU orcid ; Björklund, Sebastian ; Bost, Jeremy ; Engblom, Johan ; Christensen, Gustav LU ; Rogova, Oksana LU ; Morin, Maxim LU and Haedersdal, Merete , et al. (2025) In PLOS ONE 20(6 June).
Abstract

Purpose To evade immunosurveillance many cancers convert tryptophan (Trp) into kynurenine (Kyn), which induces immunotolerance and suppresses immune responses. Elevated Kyn amounts have been found in blood from patients with cutaneous melanoma. This study aimed to investigate whether higher Kyn abundance and lower Trp abundance can be detected on the surface of cutaneous melanoma lesions compared with adjacent non-lesional skin. Methods Sixteen patients with suspected melanomas were enrolled in this study. All lesions were excised and histopathologically diagnosed: 7 lesions were diagnosed as invasive malignant melanomas (MM), 6 as melanomas in situ (MIS), and 3 as benign lesions (BL). Non-invasive metabolite sampling was performed by... (More)

Purpose To evade immunosurveillance many cancers convert tryptophan (Trp) into kynurenine (Kyn), which induces immunotolerance and suppresses immune responses. Elevated Kyn amounts have been found in blood from patients with cutaneous melanoma. This study aimed to investigate whether higher Kyn abundance and lower Trp abundance can be detected on the surface of cutaneous melanoma lesions compared with adjacent non-lesional skin. Methods Sixteen patients with suspected melanomas were enrolled in this study. All lesions were excised and histopathologically diagnosed: 7 lesions were diagnosed as invasive malignant melanomas (MM), 6 as melanomas in situ (MIS), and 3 as benign lesions (BL). Non-invasive metabolite sampling was performed by tape stripping of suspected skin lesions and adjacent healthy non-lesional (NL) skin. Trp, Kyn, tyrosine (Tyr), and phenylalanine (Phe) were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Electrical impedance spectroscopy (EIS) measurements were conducted to assess skin barrier integrity. Results Levels of all metabolites, Tyr (x6), Phe (x6), Trp (x5), and Kyn (x3), were significantly higher in MM lesions compared with adjacent NL skin, resulting in an elevated Trp/ Kyn ratio. Trp levels increased less than Phe and Tyr levels, suggesting a potential increase in Trp depletion. Skin resistance in MM lesions was half that of NL skin. No differences were observed between MIS or BL and NL skin. Conclusions Non-invasive skin sampling revealed elevated Tyr, Phe, Trp and Kyn levels in MM skin, which is likely the result of compromised skin barrier at this stage of cutaneous melanoma.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLOS ONE
volume
20
issue
6 June
article number
e0326457
publisher
Public Library of Science (PLoS)
external identifiers
  • scopus:105009300269
  • pmid:40554511
ISSN
1932-6203
DOI
10.1371/journal.pone.0326457
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2025 Jankovskaja et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
id
efd59b64-1d86-42e3-8972-e16b21acba61
date added to LUP
2025-12-16 11:17:41
date last changed
2025-12-30 12:18:23
@article{efd59b64-1d86-42e3-8972-e16b21acba61,
  abstract     = {{<p>Purpose To evade immunosurveillance many cancers convert tryptophan (Trp) into kynurenine (Kyn), which induces immunotolerance and suppresses immune responses. Elevated Kyn amounts have been found in blood from patients with cutaneous melanoma. This study aimed to investigate whether higher Kyn abundance and lower Trp abundance can be detected on the surface of cutaneous melanoma lesions compared with adjacent non-lesional skin. Methods Sixteen patients with suspected melanomas were enrolled in this study. All lesions were excised and histopathologically diagnosed: 7 lesions were diagnosed as invasive malignant melanomas (MM), 6 as melanomas in situ (MIS), and 3 as benign lesions (BL). Non-invasive metabolite sampling was performed by tape stripping of suspected skin lesions and adjacent healthy non-lesional (NL) skin. Trp, Kyn, tyrosine (Tyr), and phenylalanine (Phe) were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Electrical impedance spectroscopy (EIS) measurements were conducted to assess skin barrier integrity. Results Levels of all metabolites, Tyr (x6), Phe (x6), Trp (x5), and Kyn (x3), were significantly higher in MM lesions compared with adjacent NL skin, resulting in an elevated Trp/ Kyn ratio. Trp levels increased less than Phe and Tyr levels, suggesting a potential increase in Trp depletion. Skin resistance in MM lesions was half that of NL skin. No differences were observed between MIS or BL and NL skin. Conclusions Non-invasive skin sampling revealed elevated Tyr, Phe, Trp and Kyn levels in MM skin, which is likely the result of compromised skin barrier at this stage of cutaneous melanoma.</p>}},
  author       = {{Jankovskaja, Skaidre and Spégel, Peter and Nielsen, Kari and Björklund, Sebastian and Bost, Jeremy and Engblom, Johan and Christensen, Gustav and Rogova, Oksana and Morin, Maxim and Haedersdal, Merete and Malmsten, Martin and Anderson, Chris D. and Ruzgas, Tautgirdas}},
  issn         = {{1932-6203}},
  language     = {{eng}},
  number       = {{6 June}},
  publisher    = {{Public Library of Science (PLoS)}},
  series       = {{PLOS ONE}},
  title        = {{Non-invasive tape sampling of tryptophan and kynurenine in relation to phenylalanine and tyrosine from melanoma and adjacent non-lesional skin : A pilot study}},
  url          = {{http://dx.doi.org/10.1371/journal.pone.0326457}},
  doi          = {{10.1371/journal.pone.0326457}},
  volume       = {{20}},
  year         = {{2025}},
}