Here's what I found a while back when seeking info about tumor necrosis. 1) Necrosis in the tumor means that the cancer cells in that area are dead. The pathologic finding of necrosis suggests a fast-growing cancer. This often happens because the tumor runs out of blood supply in the central portion. Without a blood supply, the tumor cells cannot live.
In association football, where the shoes themselves are known as football boots, there are three different cleat types. There are soft ground cleats which are made for wet weather. The soft ground cleats are always replaceable, and are almost always metal, so when they wear down they are easy to replace.
One way of grouping soccer cleats is by the type of studs they have: Molded studs and Replaceable studs. The other way of classifying cleats is by various field conditions they are proper for: Hard Ground (HG) - for playing on hard fields.