Researchers have identified 4 PNET subtypes – 2016 research
Read more in the following article by Dominik Sturm, Brent A. Orr,Umut H. Toprak, David W. Ellison, Andrey Korshunov, Marcel Kool
http://pnetcancerfoundation.com/wp-content/uploads/2017/05/Sturm-Cell-2016.pdf