How is a normal cell transformed ... assay" still used today to assess tumor growth. How do transformed cells grow? First, they no longer require contact with the surface of a culture dish.

For organs to develop, grow and regenerate, cells must proliferate. But when that process goes awry, leading to uncontrolled cell growth, cancer can emerge.

Multiple studies have now demonstrated that 4-1BBL can independently provide co-stimulatory signals to induce T cell proliferation ... it comes through recombinant proteins, antibodies, assay kits, ...