The dominant idea about how cancer gets started is called the “two-hit hypothesis.” First proposed by Alfred Knudson in 1971, it holds that a cancer starts when one cell gets a mutation in both of its copies of a gene that normally blocks cancer formation (two hits). These two mutations disable the tumor-suppressing function in that cell, which then becomes cancerous. Eventually, the idea was expanded to include two hits not necessarily in the same gene but, rather, in genes controlling the same tumor-suppressing pathway.
But a new idea is challenging the two-hit hypothesis, shifting the focus to the role of the immune system in suppressing cancers. It’s an idea… Read the rest