The editor has retracted this article because a significant proportion of the articles included in this review are inappropriate to the subject matter, incorrectly cited, or duplicated. In addition, 11 of the 55 citations refer to publications by some of the authors of this review. As this article is a literature review, the Editor-in-Chief therefore no longer has confidence in the data and conclusions presented in this article.

Francesco Ferrara does not agree to this retraction. Antonio Vitiello and Raffaele La Porta have not responded to any correspondence from the editor about this retraction.

The online version of this article contains the full text of the retracted article as Supplementary Information.