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These tumor cells were painstakingly cultivated by Yang Ping. Initially, only a small sample was taken from Sisi, and it was with that small sample that Yang Ping was able to establish this tumor cell library.
At the same time, Yang Ping also established two other cell libraries---a normal stem cell library and a teratoma cell library. Now, these two cell libraries are fine, but so many tumor cells have died off.
These tumor cells must not die off without explanation. Yang Ping decided to find out the real reason behind it.
He took half of the tumor cells and stored them in a refrigerator, hoping to slow down their deterioration temporarily, leaving them to be studied at a later time.
For the remaining tumor cells, Yang Ping placed them under an electron microscope to be photographed. Cell death is a continuous process that can be divided into many detailed steps.
