Chapter 18.5, Problem 3CC

Summary Introduction

To explain: Effect of cancer-promoting mutations on activity of proteins encoded by proto-oncogenes and tumor-suppressor genes.

Concept introduction:

Spontaneous or induced damage to cells causes mutations. The mutations in genes that regulate cell growth either inhibiting or promoting, result in abnormal uncontrolled growth. The accumulation of these mutations leads to cancer. On the basis of regulation, the genes are categorized as proto-oncogenes and tumor-suppressor genes. Proto-oncogenes are normal growth promoting genes and their mutated forms causing tumor are oncogenes. Tumor-suppressor genes normally inhibit cell proliferation and tumor formation.