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Vaupel. J Cancer Metastasis Treat 2018;4:20 Journal of Cancer
DOI: 10.20517/2394-4722.2018.30 Metastasis and Treatment

Letter Open Access

Hypoxia in prostate cancer

Peter Vaupel

Department of Radiation Oncology and Radiotherapy, Tumor Pathophysiology Group, University Medical Center, Mainz 55131,
Germany.

Correspondence to: Prof. Dr. med. Peter Vaupel, Department of Radiation Oncology and Radiotherapy, Tumor Pathophysiology
Group, University Medical Center, Langenbeckstrasse 1, Mainz 55131, Germany. E-mail: vaupel@uni-mainz.de
How to cite this article: Vaupel P. Hypoxia in prostate cancer. J Cancer Metastasis Treat 2018;4:20.
http://dx.doi.org/10.20517/2394-4722.2018.30
Received: 30 Mar 2018 Accepted: 20 Apr 2018 Published: 7 May 2018

Science Editor: Lucio Miele Copy Editor: Jun-Yao Li Production Editor: Cai-Hong Wang

Dear Editor,
I have read with great interest the review “Current challenges and opportunities in treating hypoxic prostate
tumors” by McKenna et al. . In this review, the authors present, as a key information in Table 1 of their
[1]
article, values of oxygen partial pressures (pO ) in human tumors and the respective normal tissues,
2
published earlier by our group and “adapted” by McKeown later.
[4]
[2,3]
In their article, McKenna et al. have reviewed current knowledge about the impact of the “hallmark feature”
[1]
hypoxia on pathways promoting cancer growth, malignant progression, therapeutic resistance and tumor
immune escape . Certainly, this information is of utmost interest to experimental and clinical oncologists.
[5-7]
However, since this review contains some misleading/inappropriate oxygenation data, some additional
information that may be of interest for the distinguished readership of this highly reputed journal, may
serve for clarification.

In Table 1 of their review, McKenna et al. present oxygen partial pressure (pO ) values together with oxygen
[1]
2
concentration (cO ) data. When reviewing the biological role of hypoxia in malignant tumors, authors
2
lacking an expertise in respiratory physiology often convert - without any need - the in vivo pO values,
2
originally measured in tumors (and in normal tissues) using pO histography , into O concentrations using
[2]
2
2
either Dalton’s law (only valid for gas mixtures within the airways) or Henry’s law for gases dissolved in
solutions, which cannot describe the relationship between partial pressures and concentrations of gases in
heterogeneous media (e.g., tissues with lipid-rich membranes, the cytosol and the extracellular space, the
latter with a high content of free water in cancers). Therefore, it is strongly suggested to avoid any conversion
of measured pO values into cO data since the O solubility coefficient is: (1) highly dependent on the tissue
2
2
2
water content; and (2) usually not known for heterogeneous cancer tissues in patients. In this context, it has
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