Cancer cells

Cancer cells

In cancer cells, the growth is out of control. It begins with a mutation in a portion of DNA, which leads to the production of abnormal proteins. A mutation in genes involved in cell growth (proto-oncogenes), differentiation or mitosis, can result in uncontrolled growth. The proto-oncogene becomes an oncogene (1). These abnormal proteins can behave as growth stimulating factor or cell division promoting protein. So, more growth stimulating factors are

produced and thus an imbalance between growth stimulating and growth inhibiting factors occurs. On the other hand, a tumor suppressor gene (e.g. p53, p16) can be mutated (2). This results in inactivation of the gene or in formation of abnormal and thus nonfunctional protein, leading to decreased amounts of growth inhibiting factors and proteins that inhibit cell division. A mutation in a tumor suppressor gene makes oncogene activation more likely.

1

What is NOT true?

2

Compared with benign tumours, neoplastic tumours do NOT show: 

3

What is true about a tumor suppressor gene?