**Author details**

Nikolay Petrov Botushanov1 \*, Aleksandar Nikolaev Botushanov2 and Albena Dimitrova Botushanova3

1 Department of Endocrinology and Metabolic Diseases, Medical University, Plovdiv, Bulgaria

2 Department of Propaedeutics of Internal Diseases, Medical University, Plovdiv, Bulgaria

3 Department of Clinical Oncology, Medical University, Plovdiv, Bulgaria

\*Address all correspondence to: nbotush@gmail.com

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
