Dear Colleagues,

Selenium (Se), as a key trace element, plays an important role in cellular homeostasis, influencing various biological processes including protection against oxidative stress, regulation of the immune response, and functions of the endocrine system. Its biological activity is mainly associated with selenoproteins, which contain Se in the form of the amino acid selenocysteine. These proteins, which include glutathione peroxidases and thioredoxin reductases, participate in neutralizing reactive oxygen species, limiting their harmful effects on cells. In pathology, Se deficiency or excess can lead to health disorders such as cancer, autoimmune, or neurodegenerative diseases. In turn, in therapy, Se and its compounds show potential in modulating signaling pathways associated with apoptosis, proliferation, and inflammation, which opens new perspectives in terms of treatment of chronic diseases. An increasing number of studies has also emphasized the role of Se in increasing the effectiveness of anticancer therapies and protecting healthy tissues from the toxic effects of chemotherapy and radiotherapy. In this special issue of the journal, we would like to present the latest discoveries on the molecular mechanisms by which Se is involved and its therapeutic applications. Se, through its unique biological properties, plays a key role in facilitating an understanding of the mechanisms of disease progression and the development of new therapies. Integrated studies on its molecular functions can contribute to a breakthrough in the treatment of many diseases. We address the issues of biochemical regulation of selenoproteins, the effects of Se on the cellular microenvironment in diseases, as well as its potential applications in precision medicine. I strongly encourage all authors to submit manuscripts.

Prof. Marek Kieliszek
Guest Editor