Letter to the Editor: Fletcher NM, Harper AK, Memaj I, Fan R, Morris RT, Saed GM. Molecular Basis Supporting the Associa
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LETTER TO THE EDITOR
Letter to the Editor: Fletcher NM, Harper AK, Memaj I, Fan R, Morris RT, Saed GM. Molecular Basis Supporting the Association of Talcum Powder Use with Increased Risk of Ovarian Cancer. Reprod Sci. 2019;26(12):1603–12. DOI: 10.1177/1933719119831773 Brooke T. Mossman 1 Received: 13 May 2020 / Accepted: 13 July 2020 / Published online: 19 August 2020 # Society for Reproductive Investigation 2020
To the Editor, This in vitro report from Dr. Ghassan Saed’s laboratory attempts to demonstrate a link between talcum powder use and the causation of ovarian cancers. The references, methodology, results, and conclusions are severely flawed. For example, in the Introduction, Dr. Saed states “The pathophysiology of EOC is not fully understood but has been strongly associated with inflammation and the resultant oxidative stress.” The cited review by Reuter et al. [1] details the importance of oxidative stress in a number of nonmalignant and cancerous diseases and does not discuss ovarian cancer. The feasibility of the experiments described is also questionable. Dr. Saed presents data on human immortalized macrophages, transformed ovarian epithelial cell lines, and one primary culture of normal ovarian cells. Considering the limited passaging and doubling capacity of the normal ovarian epithelial cells as described in its source information, it is impossible to envision how cells were seeded at 3 × 106 and propagated in numbers necessary for the multiple assays described. In an attempt to solubilize talc (an insoluble mineral), the toxic solvent, dimethyl sulfoxide (DMSO) was added to talc, and the talc:DMSO mixture is filtered through a 0.2-μm pore filter prior to its addition to cells. This protocol precludes the addition of talc particles, ranging from 1 to 50 μm in diameter in commercial talcs [2], to cells as particles would be filtered out prior to their addition to cells. If Dr. Saed had used microscopy to observe whether talc particles interacted with cells, he would have observed the lack of talc particles in
* Brooke T. Mossman [email protected] 1
Department of Pathology and Laboratory Medicine, Larner College of Medicine, University of Vermont, 89 Beaumont Avenue, Given C222, Burlington, VT 05405, USA
his experiments. More than likely, results are due to DMSO exposures. The concentration of DMSO used in solvent control cells should be specified. Contrary to his claims that talc induces a prooxidant state in cells, Dr. Saed neither measures antioxidant/oxidant enzyme activity nor release of reactive oxygen species directly in any of his experiments. The fact that he reports decreased gene and protein expression of SOD3 (extracellular superoxide dismutase) yet does not measure SOD1 or SOD2 that have been increased in mineral toxicity and carcinogenesis should be explained. Results using the Griess assay for detection of reactive nitrogen species are presented as an ELISA (Fig. 2C) when it is in fact a spectrophotometric assay [3]. Likewise, he claims that the MTT assay, an assay measuring
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