Tumour Markers


Oncogenesis

Human cancer development is a result of a genetic disease

protoncogenes

Tumour suppressor genes.

Regulatory expression of these genes can be seen in the normal cells and protein products of these genes are fundamental for normal cell function.

Examples:

Oncogenes: Ras, Myc, EGFR,c-erbB1,2,3.

Tumour suppressor genes: p53, Rb genes

Carcinogenesis

Multifactorial etiology.

The tumour suppressor genes or oncogenes would be altered in the presence of carcinogens:

Chemical carcinogens

Physical agents

Ionizing radiation

Viral agents

Others

Four common types of genetic changes

Deletion : Loss of tumour suppressor genes

Mutation : p53, Ras

Inversion : Relocate the the oncogenes in

Translocation to DNA areas which will leads inappropriate transcription.

Subsequent accumulation of such growth promoting genetic defects forms the basis of current multi step process of tumourigenesis.

This multi step process includes.

Initiation.

Promotion.

Tumour progression.

Many of the known oncogenes and oncosupressor genes help control mitosis and apoptosis.

Lack of this control would leads to development of malignancy.

Genetic disease.

Tumour marker

Substance or group of substance produced by the tumour

Which can be used as a indicator to detect the presence of the tumour.

A tumour marker should be indicative of :

Tumour susceptibility of the patient.

Severity or virulence of the tumour.

Prognosis of the disease.

Tumour burden (Including metastasis) .

Treatment response.

Types of tumour markers:

Histopathological markers.

Immuno markers.

Genetic markers.

Hormonal markers.

Protein products of tumours Carcino-embrionic antigen

Apoptosis related genes

Bcl2 family: Bcl2, Bcl XL , Bax , Bad.

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