Oncogenes and Their Roles in Cancer

Oncogenes and Their Roles in Cancer

Introduction to Oncogenes

Oncogenes are mutated or overexpressed versions of normal genes (proto-oncogenes) that drive uncontrolled cell growth and contribute to the development of cancer. They encode proteins involved in cell signaling, growth, and division. Understanding the function and associated tumors of oncogenes is crucial in cancer biology and therapy.

Growth Factor Genes

• HST: Encodes fibroblast growth factor. Associated Tumor: Stomach carcinoma

• SIS: Encodes the β subunit of platelet-derived growth factor. Associated Tumor: Glioma (brain tumor)

• KS3: Encodes fibroblast growth factor. Associated Tumor: Kaposi sarcoma

Growth Factor Receptor Genes

• RET: Receptor tyrosine kinase. Associated Tumor: Multiple endocrine neoplasia; thyroid carcinoma

• ERBB: Epidermal growth factor receptor. Associated Tumor: Glioblastoma (brain tumor); breast carcinoma

• ERBA: Thyroid hormone receptor. Associated Tumor: Acute promyelocytic leukemia

• NEU (ERBB2): Receptor protein kinase. Associated Tumor: Neuroblastoma; breast carcinoma

• MET: Receptor tyrosine kinase. Associated Tumor: Hereditary papillary renal carcinoma; hepatocellular carcinoma

• KIT: Receptor tyrosine kinase. Associated Tumor: Gastrointestinal stromal tumor syndrome

Signal Transduction Genes

• HRAS: GTPase. Associated Tumor: Carcinoma of colon, lung, pancreas

• KRAS: GTPase. Associated Tumor: Melanoma, thyroid carcinoma, acute monocytic leukemia, colorectal carcinoma

• NRAS: GTPase. Associated Tumor: Melanoma

• BRAF: Serine/threonine kinase. Associated Tumor: Malignant melanoma; colon cancer

• ABL: Protein kinase. Associated Tumor: Chronic myelogenous leukemia; acute lymphocytic leukemia

• CDK4: Cyclin-dependent kinase. Associated Tumor: Malignant melanoma

Transcription Factor Genes

• MYC: DNA-binding protein. Associated Tumor: Neuroblastoma; lung carcinoma

• MYB: DNA-binding protein. Associated Tumor: Malignant melanoma; lymphoma; leukemia

• FOS: Interacts with JUN oncogene to regulate transcription. Associated Tumor: Osteosarcoma

Summary Table: Examples of Oncogenes and Their Roles in Cancer

Oncogene	Function	Associated Tumor
HST	Fibroblast growth factor	Stomach carcinoma
SIS	β subunit of platelet-derived growth factor	Glioma (brain tumor)
KS3	Fibroblast growth factor	Kaposi sarcoma
RET	Receptor tyrosine kinase	Multiple endocrine neoplasia; thyroid carcinoma
ERBB	Epidermal growth factor receptor	Glioblastoma; breast carcinoma
ERBA	Thyroid hormone receptor	Acute promyelocytic leukemia
NEU (ERBB2)	Receptor protein kinase	Neuroblastoma; breast carcinoma
MET	Receptor tyrosine kinase	Hereditary papillary renal carcinoma; hepatocellular carcinoma
KIT	Receptor tyrosine kinase	Gastrointestinal stromal tumor syndrome
HRAS	GTPase	Carcinoma of colon, lung, pancreas
KRAS	GTPase	Melanoma, thyroid carcinoma, acute monocytic leukemia, colorectal carcinoma
NRAS	GTPase	Melanoma
BRAF	Serine/threonine kinase	Malignant melanoma; colon cancer
ABL	Protein kinase	Chronic myelogenous leukemia; acute lymphocytic leukemia
CDK4	Cyclin-dependent kinase	Malignant melanoma
MYC	DNA-binding protein	Neuroblastoma; lung carcinoma
MYB	DNA-binding protein	Malignant melanoma; lymphoma; leukemia
FOS	Interacts with JUN oncogene to regulate transcription	Osteosarcoma

Key Concepts

• Oncogenes are mutated proto-oncogenes that promote cancer by driving cell proliferation.

• They encode proteins such as growth factors, receptors, signal transducers, and transcription factors.

• Specific oncogenes are associated with particular types of cancer, aiding diagnosis and targeted therapy.

Example

• BRAF mutations are commonly found in malignant melanoma and colon cancer, and targeted therapies have been developed to inhibit BRAF activity in these cancers.

Additional info: Oncogenes are a major focus in cancer research, as their identification has led to the development of targeted cancer therapies, such as tyrosine kinase inhibitors and monoclonal antibodies.